OPERATING MANUAL

XL2 HANDHELD AUDIO AND

ACOUSTIC ANALYZER
Contact NTi Audio at

Headquarter +423 239 6060 info@nti-audio.com

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www.nti-audio.com

NTi Audio AG
Im alten Riet 102, 9494 Schaan
Liechtenstein, Europa

is an ISO 9001:2015 and ISO 14001:2015 certified company.

Firmware V4.84
Version 4.84.00 / Aug 23

All information subject to change without notice.

© All rights reserved.
® XL2, XL2-TA, EXEL, M2230, M2340, M2211, M2215, M4261, MA220, MA230,
™ M2230-WP, M2340-WP, M4261-WP, WP30-90, WP30-150, WP61 and Minirator are trademarks Made in
of NTi Audio. Sw i t ze r l a n d
 Table of Contents

Table of Contents

1. Introduction......................................................................5 5. Acoustic Analyzer...........................................................64

FFT Analysis + Tolerance...............................................64
2. Overview...........................................................................7
Reverberation Time....................................................... 74
Operation........................................................................9
Polarity..........................................................................86
The Screen Display....................................................... 11
Delay Time....................................................................90
3. Getting Started..............................................................14 1/12 Octave + Tolerance (optional)................................96
Power Supply ............................................................... 14 Noise Curves (optional)............................................... 108
Attaching the Hand Strap.............................................. 17 Speech Intelligibility STIPA (optional).......................... 118
Unfolding the Stand...................................................... 18
6. Audio Analyzer.............................................................135
Connecting the XL2 ..................................................... 18
RMS / THD+N............................................................. 135
Switching the XL2 On and Off......................................20
Oscilloscope............................................................... 138
Select Measurement Function......................................20
Calibration prior Measurement.....................................21 7. Vibration Meter.............................................................139
VibMeter / Spectrum.................................................. 139
4. Sound Level Meter.........................................................22
FFT Analysis + Tolerance............................................. 146
Overview......................................................................26
Oscilloscope............................................................... 150
Sound Level Meter - Getting Started............................34
1/12 Octave + Tolerance (optional).............................. 151
RTA Measurement - Getting Started............................39
Reporting......................................................................43 8. Calibration....................................................................156
Wav-File Recording.......................................................46
9. Profiles..........................................................................163
Events (optional)...........................................................49
Limits............................................................................56 10. Spectral Limits Option (Capture + Tolerances)........ 170
Correction Value KSET..................................................58 11. System Settings......................................................... 183
Locked Run Mode.........................................................62 Settings....................................................................... 183
3
 Table of Contents

Vibration...................................................................... 186 Service and Repairs....................................................272

Scheduler.................................................................... 187 Calibration Certificate..................................................272
Options....................................................................... 189 Declaration of Conformity........................................... 274
Information................................................................. 190
23. Technical Data XL2..................................................... 276
12. Data Management..................................................... 191
24. Technical Data Microphones.....................................288
Record Voice Notes..................................................... 197
Recall Measurements.................................................203 25. Technical Data PreAmplifier.......................................298
Append Measurements .............................................205
Appendix..........................................................................299
13. XL2 Projector PRO Software..................................... 210 Appendix 1: Standard - Optional Features..................299
Appendix 2: Factory Default Profiles..........................303
14. Data Explorer (optional)............................................212
Appendix 3: Description Sound Levels.......................308
15. Building Acoustics (optional)....................................214 Appendix 4: Common Sound Levels........................... 313
Appendix 5: Vibration Meter Functions....................... 319
16. Room Acoustics (optional)........................................216
Details IEC 61672 & IEC 61260........................................320
17. Sound Power (optional)............................................. 218
General Information....................................................322
18. Unattended Noise Monitoring......................................220 Class 1 Sound Calibrator.............................................325
Accessory...................................................................325
19. Time Synchronization...............................................226
Level Linearity.............................................................326
20. Remote Measurement...............................................230 Level Linearity of Octaveband-Spectrum....................328
21. Microphones ..............................................................232 Level Linearity of Third-Octaveband-Spectrum...........329
Self-generated Noise with Microphone......................330
22. Further Information...................................................246 Frequency Response Corrections...............................332
My NTi Audio..............................................................246 Frequency Weighting..................................................336
Firmware Update........................................................249 Directional Response (dB)..........................................337
Options.......................................................................250
Warranty Conditions...................................................271 Information for Calibration.............................................342

4
 Introduction

1. Introduction
Thank you for purchasing the XL2 Audio and Acoustic Analyzer. - Room Acoustics
The XL2 Analyzer forms the unique combination of a state-of- - Building Acoustics
the-art Sound Level Meter, a comprehensive Acoustic Analyzer - Reverberation Time
as well as a powerful Audio Analyzer. The wide range of func- - Noise Curves
tionalities is tailored for: • Industrial Quality Control
• Condition Monitoring
• Evacuation Systems
- Speech Intelligibility
• Electroacoustic Installations
- Installed Sound
- AV Installations How to Read this Manual
- Cinemas The XL2 push buttons are displayed as icons , , , ,
• Noise Measurement , , , , . A detailed description of the push buttons is
- Unattended Noise Monitoring listed in the chapter Overview - Operation.
- Environmental Noise
- Occupational Health Menu items displayed on the XL2 page screens are shown in
- Vehicle Noise this user manual by a bold font, e.g., SLMeter, Parameter, ...
- Sound Power
• Live Sound
- Sound Level Monitoring
- Front of House
- PA Rental
• Broadcast
• Room & Building Acoustics

5
 Introduction

Product Configurations XL2 + • XL2 Analyzer

The following items are included with the respective model: M2211 • M2211 Measurement Microphone
consisting of
XL2 • XL2 Analyzer - Microphone PreAmplifier MA220
without • USB Flash Drive with test signals - Microphone Capsule 7052
Micro- • USB cable • 33 mm Windscreen
phone • Li-Po battery • Microphone-holder
• Hand strap with Adapter 5/8“ - 3/8“
• Operating manual • USB Flash Drive with test signals
• Li-Po battery
XL2 + • XL2 Analyzer • USB cable
M2230 • M2230 Measurement Microphone • Hand strap
consisting of • Operating manual
- Microphone PreAmplifier MA220
- Microphone Capsule MC230 or MC230A XL2 + • XL2 Analyzer
• 50 mm Windscreen M4261 • M4261 Measurement Microphone
• Microphone-holder MH01 • 33 mm Windscreen
with Adapter 5/8“ - 3/8“ • Microphone-holder
• Individual Frequency Response Chart with Adapter 5/8“ - 3/8“
• USB Flash Drive with test signals • USB Flash Drive with test signals
• Li-Po battery • Li-Po battery
• USB cable • USB cable
• Hand strap • Hand strap
• Operating manual • Operating manual

6
 Overview

2. Overview 11 Tripod Mount

XL2 interfaces: 10 Speaker

6 Digital I/O 9
Headphone
Output
1 5 USB Connector
XLR Input 3
Voice Note Input 8 TOSLink Output
2 4 DC Power Socket
RCA Input 7 SD Card

7
 Overview

1 XLR Signal Input 7 SD Card

Either a balanced audio signal, an NTi Audio measure- For storing data, screenshots, voice notes, wav-files -
ment microphone or the microphone pre-amplifier MA220 required to power on and run the instrument.
plug directly into the XLR input. The Automated Sen-
sor Detection (ASD) technology reads the electronic 8 TOSLink Output
data sheet of any connected NTi Audio device after the 24 bit linear PCM audio signal output. For future use; not
48 V microphone phantom power is activated. active at this time.

2 RCA Input 9 Headphone Output

Unbalanced audio signal input. The XLR/RCA input signals are routed to the headphone
connector (3.5 mm Minijack; mono monitor wired to both
3 Voice Note Input channels of stereo jack). Connecting headphones mutes the
Internal microphone for recording voice notes and measur- internal speaker. To connect the headphone output direct-
ing polarity and delay time. For polarity measurements, an ly to a line input, a load impedance < 8 kOhm is required
external microphone may also be used. for proper operation. This can be achieved by inserting a
1 kOhm resistance between tip and ground of the output
4 DC Power Socket jack.
Socket for mains power adapter. Further details in the chap-
ter Power Supply in this manual. 10 Speaker
The XLR/RCA input signals are routed to the speaker. Press
5 USB Connector the speaker button to toggle the speaker on/off. Press
Mini-B USB connection, for accessing the SD Card. and hold the speaker button to access the volume control.
Set the speaker level with the rotary wheel .
6 Digital I/O
Programmable digital inputs/outputs. 11 Tripod Mount
Mechanical mount for attaching the XL2 to a tripod or mi-
crophone stand.
8
 Overview

Operation 2 Volume of Speaker and Headphone Output

• Press the button briefly to enable or disable the
speaker.

9 8 7 6
 The speaker is activated and the speaker or headphone
icon appears in the upper menu bar.

• Press and hold the speaker button .

 A pop-up window for volume is displayed.

1 5

2 3 4

1 Page Control
Switches among various screens depending on the menu
function selected.

9
 Overview

• Hold the speaker button down and adjust the level • FFT + Tol: The limit button lights up green for results
of the speaker and headphone outputs with the rotary within tolerance and red for out-of-tolerance results.
wheel . Digital gain control prevents gain increases be- • Polarity: The limit button lights up green at positive polar-
yond a level that will cause signal clipping. The maximum ity and red at negative polarity.
gain setting depends on the connected input signal. • 1/12 Oct + Tol: The limit button lights up green for results
• The headphone output provides a linear output signal us- within tolerance and red for out of tolerance results.
ing the SLMeter function over a measurement range of
57 dB. The minimum Z-weighted sound pressure level at 5 Pause
reference sensitivity is: Pauses the current measurement. Press the pause button
- M2230, M2340: 58 dB or the start/stop button to continue the measure-
- M2211: 64 dB ment. The data logging is continued in the function SLMe-
- M4261: 66 dB ter/RTA during the pause period and listed in the log file.

3 Power & Backlight 6 Start/Stop

The power button switches the instrument on. The XL2 is Starts and stops a measurement.
immediately ready for operation. Holding down the power
button for one second switches the XL2 off. Additionally, 7 Enter
a brief press of the power button toggles the backlight Confirms a selection.
during operation.
8 Rotary Wheel
4 Limit Selects the required measurement function or the individu-
• SLMeter: The limit button lights up green, yellow or red al measurement parameter.
according to the settings in the Limit page. Press the
limit button to access the Limit page. For more details 9 ESC
visit the chapter Sound Level Meter: Limits. Terminates an entry, returns to the top menu level or closes
an open window.

10
 Overview

The Screen Display

The XL2 displays the actual sound levels also in case of no
measurement has been started. Any displayed averaged level
refers to the previous measurement period. The XL2 shows
four lines in case of no previous measurement period is ap- 2 3 4 5 6 7 8 9
plicable.

Display Contrast Setting

• Hold down escape and turn the rotary wheel until the
desired contrast is reached.

Updating of display
• Numeric values
Updated every 500ms independent of the measurement
function. The maximum time span between the end of
the measurement period and the first test result display is
500ms.
• Graphs and spectra
Updated every 50ms
The display is updated continuously during measurement.

11
 Overview

1 Measurement Results 3 Page Selector

Individual level measurement results. Toggles between available measurement and result pages
within the same function menu. Alternatively use the page
2 Main Menu button .
SLMeter/RTA SPL & RTA Measurement
4 Input Selector
FFT + Tol FFT Analysis with optional Tolerance Select XLR or RCA input connectors as the source.
Management
RT60 Reverberation Time 5 Memory Menu
Polarity Polarity The memory menu is used for data storage management.
One of the following symbols flashes before or after start-
Delay Time Delay Time ing the measurement:
RMS/THD+N RMS Level and Distortion
9-8-7 Time in seconds until instrument is settled and
Oscilloscope Scope
measurement will start.
1/12 Oct + Tol Spectral Analysis with Tolerance Man-
agement (optional) RUN Indicates the ongoing measurement.
Noise Curves Noise Curves
LOG Indicates the ongoing measurement with data
STIPA Speech Intelligibility (optional) logging.
Cinema Meter Calibration and verification of cinema
loudspeaker systems (optional) AUD Indicates the ongoing measurement with data
logging and audio recording.
Calibrate Calibration Menu for microphone
Profile ... Store and load measurement profiles Evt Indicates an ongoing triggered-event recording.
System System Settings

12
 Overview

After a completed measurement, the memory symbol 9 Battery Symbol

indicates a non-saved measurement report. Your measure- The battery symbol indicates the battery status as follows:
ment needs to be stored manually. For more details visit
the chapter Data Management. Using rechargeable Li-Po battery:
Level indication 100% (U > 4.0 Volt).
6 Speaker/Headphone (Battery charges when mains adaptor connected)
Indication of enabled rear speaker or headphone output.
Level indication:
75%: U = 3.9 - 4.0 Volt
7 Phantom Power Supply
50%: U = 3.8 - 3.9 Volt
25%: U = 3.7 - 3.8 Volt
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor. Level indication 0% (U < 3.7 Volt). The battery is
almost empty and must be recharged.
ASD An NTi Audio measurement microphone with The battery is being recharged by the mains
automated sensor detection ASD is connect- power adapter.
ed. The XL2 reads the electronic data sheet of The XL2 is connected via USB to a computer.
the microphone and switches the 48 V Phan- The battery charge level decreases slowly dur-
tom power automatically on ing XL2 usage.

48V Phantom power is switched off.

Using standard AA batteries:
8 Real-Time Clock No level indication as long as U > 4.5 Volt.
The real-time clock is set in the System menu.
Level indication 0% (U < 4.5 Volt). The batteries
are almost empty and should be replaced.

Using mains or supply:

No indication of battery status.
13
 Getting Started

3. Getting Started Operation using Mains Power Supply

You can also operate the XL2 with the optional NTi Audio Mains
Power Supply Power Adapter. During such operation it is recommended to
leave the batteries inside the instrument.
The XL2 offers flexible power management options and can be
operated either by
• Replaceable, rechargeable lithium-polymer (Li-Po) battery Mains Power Adapter
(included with the XL2 Analyzer) • Electrically-isolated, linear DC power supply
• 4x AA-batteries • A decreased THD+N performance will oc-
• Mains Power Adapter cur with unbalanced input signals when us-
ing switching-type power supplies (approx.
The new battery is charged to approximately 50% and should 3 dB).
be fully charged before use with: • Non-NTi Audio power supplies may have fur-
ther negative effects on measurements.
Battery Charger Charging Time: approx. 3 hours • Damage caused by using an inappropriate ex-
(optional) NTi Audio #: 600 000 332 ternal DC supply is not covered by warranty.

Mains Power Charging Time: approx. 6 hours

Adapter Leave the battery inside and switch off
(optional) the XL2 . Running the XL2 during
charging prolongs the charging time. DC Power supply specifications
NTi Audio #: 600 000 333 • Voltage: 7.5 - 20.0 Volt
• Power: minimum 6 Watt
USB Power Charging Time: approx. 6 hours • Connector type: 2.1 x 5.5 x 9.5 mm
from PC Switch off the XL2 for charging. The • Polarity: .
charging power is equal or less than the
power consumption.
14
 Getting Started

Rechargeable Li-Po Battery

• Open the battery cover at the rear of the instrument.
• Insert the rechargeable battery with the contacts edge first.
• Close the battery cover.

3.
Switch off the XL2 for faster recharging by
mains power adapter or USB connection.
2.

Caution
• Switch the XL2 off prior opening the battery
1.
cover in order to prevent any electronic dis-
charges.
• Avoid short-circuits.
• Operate and charge the battery between 0°C
and 45°C (32°F - 113°F).
• Do not heat the battery above 60°C.
• Do not place the battery in or near fire.
• Do not solder directly on to the battery.
• Do not disassemble the battery.
• Do not insert the battery in reverse polarity.
• Remove the battery for applications with a
connected mains power adapter over mul-
tiple weeks.

15
 Getting Started

AA-Batteries
Alternatively, the XL2 can be powered by AA type batteries

• Open the battery cover.

• Insert 4 fully-charged AA batteries, observing correct polarity
of the +/- indications in the battery compartment.
2.

 The polarity alternates with successive batteries.

• Close the battery cover.

1.
• Switch the XL2 off prior opening the battery
cover in order to prevent any electronic dis-
charges.
• Use only similar batteries from the same
manufacturer.
• Replace discharged batteries with new ones.
• Do not mix used and new batteries.
• During operation, the battery temperature
may increase noticeably. This is not a defect.
• Remove all batteries if the XL2 is not to be
used over a long period of time.

16
 Getting Started

Attaching the Hand Strap

To avoid accidentally dropping the XL2, a hand strap is supplied
with the instrument.

• Pull the loop of the hand strap through the opening.

• Pull the other end of the hand strap through the loop.
• Pull the hand strap tight.

1. 2. 3.

17
 Getting Started

Unfolding the Stand Connecting the XL2

A convenient table stand is attached to the rear of the instru- Acoustic Measurements
ment. Connect an NTi Audio measurement microphone to the XLR
input connector of the XL2.
• Unfold the stand and rest the XL2 on a flat surface.

18
 Getting Started

Audio Measurements: XLR Connection Audio Measurements: RCA Connection

• Connect the source to the XL2 with an XLR cable. • Connect the source to the XL2 with an RCA (cinch) cable.
• Select the XLR input in the menu. • Select the RCA input in the menu.

19
 Getting Started

Switching the XL2 On and Off Select Measurement Function

Switching On the XL2 • Navigate with the rotary wheel to the main menu bar.
• Confirm with enter to select the measurement function.
Press power to switch on the XL2.
 The main menu window opens
 There is a brief sound of relays and the display illuminates.

Switching Off the XL2

Press power and hold it down for one second to switch off
the XL2.

Main menu with enabled options

• Scroll up/down with the rotary wheel to select the re-

quired function and confirm with enter .

 The measurement function is selected.

20
 Getting Started

Setting the Parameters with the Rotary Wheel Calibration prior Measurement
• Turn the rotary wheel to navigate within the display
screen. We recommend the daily calibration of the XL2 Analyzer with
the Sound Calibrator. This ensures accurate measurement re-
 The selected parameter is highlighted with a black back- sults.
ground.
For more details see chapter Calibration.
• Confirm with enter .

 The parameter display flashes and/or available parameters

or settings are shown.

• Turn the rotary wheel to set the parameter or toggle with

enter through the settings.
• Confirm with enter .

 Now the parameter is set.

21
 Sound Level Meter

4. Sound Level Meter

The XL2 provides, together with the measurement micro- Extended Acoustic Pack (optional)
phone, a precise sound level meter for monitoring live sound The Extended Acoustic Pack offers the following additional fea-
events and/or environmental noise. tures for sound-level and acoustic measurements:

The Type Approval Option upgrades the instrument to the • SLMeter/RTA function
XL2-TA, the sound level meter dedicated to certified measure- - Recording of linear wav-files (24 bit, 48 kHz)
ments. The XL2 with the M2230 microphone forms a type ap- - Percentiles for wide band and spectrum with flexible set-
proved sound level meter offering class 1 performance accord- ting from 0.1% to 99.9%
ing IEC61672 (see chapter Options and Accessories) - Sound Exposure Level LAE
- 100 ms logging
For example, Actual, Lmin, Lmax, Leq with frequency weight- - RTA logging of Lmin and Lmax
ing A, C and Z and time weighting F and S can be measured - Event-triggered audio and data recording
at the same time. All measurement results are simultaneously - Time weighting: Impulse (LxI, LxIeq with x= A, C, Z)
available. You may log all acquired level information, including - True peak level in 1/1 and 1/3 octave resolution
real-time information, onto the removable SD Card. To com- - Clock-impulse maximum level (TaktMax) in accordance
plete the documentation of the measured sound pressure lev- with DIN 45645-1 and DIN 45657
els, the XL2 offers wav-file recording, as well as the facility - Impulsiveness detection in accordance with BS4142:2014
to add voice notes for each measurement. The XL2 measures and NordTest ACOU 112
correction values between the loudest point of the live event • FFT function
and the actual measurement positions in accordance with DIN - High-resolution Zoom-FFT with selectable frequency
15905-5 and V-NISSG. In parallel with the wide band param- ranges and resolution up to 0.4 Hz in the range of 5 Hz to
eters, the XL2 measures the real-time spectrum either in 1/1 or 20 kHz
1/3 octave-band resolution. The RTA perfectly suits tasks such • RT60 function
as optimization of sound systems - Reverberation time in 1/3 octave resolution
• 1/12 octave Spectral Analyzer
22
(requires Spectral Limits Option)
- Recording of linear wav-files (24 bit, 48 kHz)
 Sound Level Meter

The sound level meter offers different pages: 123 SLMeter: Sound Level Meter
Displays the selected broadband sound level results. You can
Page Selection using the Page Button change the font size of the result. Depending on the font size
• Press page to toggle between the 123 SLMeter page chosen, the XL2 shows 3 or 5 results simultaneously. Individual
and the RTA page. frequency weighting, time weighting, actual, minimum, maxi-
mum and correction values can be chosen for each displayed
Page Selection using the Rotary Wheel result.
• Select the page 123 SLMeter with the rotary wheel .
• Confirm with enter .
RTA: Real-Time Spectrum
Displays the 1/3 or 1/1 octave spectrum of the selected sound
level within the audio band. Additionally the wide band result is
shown graphically by a bar.

Reporting: Report Setting

Here you set which sound pressure levels shall be stored in a
.txt file after the completed measurement. Choose between:

ALL Stores all sound pressure levels.

Selected Stores up to 10 different individually-defined

sound pressure levels.
Menu with enabled options

For details refer to the chapter Reporting.

 You have selected the individual sound level meter page.

23
 Sound Level Meter

Logging: Setup of Data Logging Limit LED: Limit Setting

The XL2 features a powerful sound level meter data logger, Here you set the function of the limit LED , thereby highlight-
which allows you to record all required sound level values dur- ing any sound level that exceeds the pre-set limits in orange
ing the measurement. In the logging page you set which sound or red color. Further, external peripherals are controlled by the
pressure levels shall be logged over time. For details refer to optional Serial I/O Interface based on the sound level, such as
the chapter Logging. Choose between: displaying sound levels on a large external red-orange-green
lamp. For details refer to the chapter Limits.
ALL Logs all sound pressure levels.

Selected Logs up to 10 different individually-defined sound KSET Correction: Setup of Correction Values
pressure levels. This page provides a wizard to measure correction values,
which could be helpful for compliant sound level monitoring
of live events. It measures the correction values between
Event Trigger: Event Setting (optional) the actual measurement position and the loudest posi-
The event function is available with the optional Extended tion accessible by the audience. The XL2 displays and logs
Acoustic Pack. The XL2 event feature offers the following func- the selected sound pressure levels including the correction
tionalities: values, allowing the sound engineer to monitor the sound
• Automated event triggered at noise levels above/below a level at the loudest position in the audience. The measure-
preset value including setting markers for specific noise cat- ment meets the requirements of the standards DIN15905-5
egories. Application example: Recording the noise level for and V-NISSG. For details refer to chapter Correction Value
LAF > 80 dB. KSET.
• Event triggered by external key press of the XL2 Input Key-
pad. You can utilize four keys (1-4) to categorize any noise of
interest or noise to be later excluded in the post-processing.
A typical application is categorizing any annoying industrial
noise by persons living in the neighborhood.

24
 Sound Level Meter

Set EQt, L%: Selection of measured levels

This page allows setting the following levels:
• Moving Time-average Sound Level
Gliding Leq with selectable time window from one second to
one hour. Four individual levels can be configured. This level
is also called “running Leq,T” or “sliding Leq,T”.
• Percentile Sound Level
- Allows the individual configuration of seven statistic lev-
els from 0.1% to 99.9% (optional with Extended Acoustic
Pack).
- The Broadband Source for the calculation of the level sta-
tistics can be chosen from a set of different levels with
either a frequency weighting A, C or Z. The time weight-
ings F, S and the moving time-averaged sound level for one
second are supported.

25
 Sound Level Meter

Overview
Numeric Result Page Real-Time Analyzer Page
The numeric result page 123 SLMeter displays the selected The real-time analyzer page RTA measures and displays
broadband sound level results. You can change the font size of the 1/3 or 1/1 octave spectrum from 6.3 Hz to 20 kHz including
the result. Depending on the font size chosen, the XL2 shows wideband results. The real-time spectrum RTA is measured in
three or five results simultaneously. Individual frequency parallel with the A and Z-weighted wideband levels.
weighting, time weighting, actual, minimum, maximum and
correction values can be chosen for each displayed result.
8 17

16
9
15
10
1
11

12
14
2

3
13
7
6

4 5

26
 Sound Level Meter

1 Sound Level Result 1 4 Input Range

All sound levels are measured and logged simultaneously. The XL2 Analyzer provides three input ranges to accom-
You select which sound levels should be displayed. modate the wide range of input signals. The individual rang-
es are based on the microphone sensitivity setting in the
Change Parameter calibration menu of the XL2. For example, at a sensitivity
• Turn the rotary wheel to select the parameter Lxx. S=20mV/Pa the input ranges are
• Press enter to open the selection menu and choose • Low: 10 - 110 dBSPL
the wideband sound pressure level to be displayed. • Mid: 30 - 130 dBSPL
• Turn the rotary wheel to select the required test result • High: 50 - 150 dBSPL
parameters and confirm with enter .
Select the lowest possible input range according to the
Change Font Size maximum level expected during the measurement; e.g., if
• Turn the rotary wheel to select the actual test result. the sound pressure will always be below 110 dBSPL, then
• Press enter 1x, 2x or 3x to set the font size to small, select the lowest input range 10 - 110 dBSPL.
medium or large.
5 Run Indication
The XL2 shows 3 sound levels on the display if a large font The run indication shows the measurement status running,
is chosen, otherwise it shows 5 sound levels. paused or stopped. Various measurement settings are
locked during ongoing measurements, such as changing
2 Sound Level Result 2 & 3 the input ranging or the preset measurement time.
Follow the setting instructions for sound level result 1.

3 Sound Level Result 4 & 5

To display sound level results 4 & 5, choose a smaller font
for all results. Follow the setting instructions for sound level
result 1.

27
 Sound Level Meter

6 Actual Measurement Time

Counts actual measurement time in hrs:min:sec. Supports Timer Mode Repeat
time modes: continuous, single and (synchronized) repeat. Provides automated repeated measurements with
user-defined, preset measurement time cycles.
Timer Mode Continuous • Set the required measurement time.
(applicable for standard measurements) • Press start .
All values are recorded and monitored continu-
ously after starting a measurement with start .  The actual measurement time counts back to
The actual measurement time is shown. zero. When the preset measurement time has
elapsed, the measurement time and the mea-
Timer Mode Single surement results are reset and a new mea-
Automatically stops the measurement after the surement is started. All measurement results
pre-set measurement time. of the previous cycle are reset.
• Set the required measurement time.
• Start the measurement . • Press stop to complete the measurement.

 The actual measurement time counts back to zero and

the measurement ends.

• All measurement results may be recalled.

28
 Sound Level Meter

8 Phantom Power Supply

Timer Mode Repeat Synchronized
Provides automated repeated measure- 48V The XL2 provides 48 V Phantom power supply
ments synchronized to the XL2 real-time clock. to the connection microphone or sensor.
Press start to begin the measurement.
In order to align the selected preset measurement ASD An NTi Audio measurement microphone with
time with the real-time clock, the XL2 shortens automated sensor detection ASD is connect-
the first cycle to match the real-time clock syn- ed. The XL2 reads the electronic data sheet of
chronization. All following measurement cycles the microphone and switches the 48 V Phan-
are synchronized to the real-time clock. tom power automatically on

For example, the cycle time setting is 30 minutes 48V Phantom power is switched off.
and the measurement starts at 7.50 a.m. -> the
first test cycle measures from 7.50 - 8.00 a.m. 9 Result Symbols / Capture
Thereafter a new test cycle starts automatically This field offers two functions:
for 30 minutes. The 30-minute cycles repeat until
the measurement is stopped. • Symbols for measurement results 15

The measurements in the synchronized repeat Upper RTA parameter displayed as line.
timer mode start exactly on the half or full hour in
accordance with DIN 15905. Lower RTA parameter displayed as bargraph.

7 Preset Measurement Time

Adjustment of preset measurement time for single and re-
peat timer setting.

29
 Sound Level Meter

• Capture 11 Y-Scale setting

One of the displayed RTA readings may be captured. Any • Select the Y-Axis with the rotary wheel and confirm
measurement data can then be compared with this cap- with enter .
tured reference live on the XL2 Analyzer. For example, • Select the zoom factor between 20, 10, 5, 2.5 dB/div
compare the RTA spectrum of the left and right speakers. and confirm with enter .
• Select the parameter to be captured. • Scroll up and down with the rotary wheel to select the
• Confirm with enter , to capture the reading. Y-axis range.
• Select the upper RTA parameter 15 and choose • Confirm with enter .
Capt.
• Confirm with enter . 12 RTA Measurement Result
Real-time analyzer results in 1/1 octave or 1/3 octave band
 The lower RTA reading can be compared with the previ- resolution. Adjust the resolution at 17 .
ously-captured reference data.
13 X-Scale setting
10 Measurement Result Toggles X-scale range between
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of 20 Hz - 20 kHz RTA levels including wide band results
the band pointed to by the arrow.
6.3 Hz - 8 kHz RTA levels including wide band results
Upper parameter displayed as line.
6.3 Hz - 20 kHz RTA levels
Lower parameter displayed as bargraph.
• Select the X-Axis with the rotary wheel and confirm
with enter .
• Toggle with the rotary wheel between the ranges.
• Confirm with enter .

30
 Sound Level Meter

14 Broadband Results The cursor readout may be set manually to any

Actual sound level. frequency band or wide band level. The readout re-
The broadband sound pressure level Leq, Lmin, Lmax and mains at the selected frequency.
Live are displayed here. The Live level is displayed with • Select the frequency with the rotary wheel .
time weighting Fast. • Press enter .
• Select the frequency of interest.
A A-weighted broadband sound pressure level • Confirm with enter .

Z Broadband sound pressure level without any fre-  The cursor readout 11 displays the measure-
quency weighting ment results of the selected frequency band.

15 Readout Frequency 16 Setting of Test Result Resolution

You may select any frequency to read out individual levels. Set the RTA result display to 1/1 octave or 1/3 octave band
The selected frequency is indicated by the cursor arrow. resolution as follows:
• Turn the rotary wheel to select the parameter 17 .
Choose between the following settings: • Press enter to toggle between 1/1 OCT and 1/3 OCT
and set this parameter.
The cursor follows automatically the highest level,
e.g. tracing feedback frequencies at live sound.
• Select the frequency with the rotary wheel .
• Press enter .
• You may readout any individual frequency.
• Return to auto frequency with enter .

 The cursor returns to the frequency with high-

est level bar.

31
 Sound Level Meter

17 Measurement Unit • The measured sound pressure level is just above the residual
Select the measurement unit as follows: noise of the connected NTi Audio measurement microphone.
This reduces the measurement accuracy -> choose another
dB Sound level in dBSPL microphone designed for low level measurements.
This measurement unit is permanently selected
when an NTi Audio measurement microphone
with electronic data sheet is connected.

dBu Input level in dBu

dBV Input level in dBV

V Input level in Volt

LOW - Indication

The low indicator for an individual level “<” is displayed when: The low condition is registered in the log and report files in the
• The measured sound pressure level is below the selected column “Low(eq/peak)“ individually for all frequency weight-
linear measurement range. In this case the results shown ings, the RMS and the peak levels.
are most likely higher than the actual sound pressure level ->
choose the next lower measurement range.

32
 Sound Level Meter

Overload Indication

In case the measurement result exceeds the preset measure-

ment range, then limit arrows indicate this overload condi-
tion. The arrows are displayed for as long as the overload
exists, and at least for a minimum of 1 second. Furthermore,
such an overload condition triggers the OVR indication in the
bottom line, which remains displayed for the complete mea-
surement period. These overload indications are reset at the
start of a new measurement. All overload conditions are regis-
tered in the log and report files.

Possible causes for exceeding measurement ranges are

• The measured sound pressure level exceeds the pre-set
measurement range during the measurement period. Once
this happens, the OVR indication remains displayed for the
complete measurement period -> select the next higher
measurement range or reduce the input signal level as ap-
plicable.
• The input level is near the maximum level of the connected
NTi Audio measurement microphone.

33
 Sound Level Meter

Sound Level Meter - Getting Started Select Displayed Test Result

This example describes the setting of the commonly-used ac-
Test Preparations tual sound pressure level LAF (level L, frequency weighting A,
• Connect the measurement microphone to the XL2. time weighting F).
• Switch on the XL2 .
The XL2 reads the electronic data sheet of any connected NTi • Select the first parameter setting with the rotary wheel .
Audio ASD microphone and switches the 48 V phantom power • Confirm with enter .
automatically.

 The 48 V phantom power indication in the upper menu bar

changes to ASD. The XL2 is ready for acoustic measure-
ments.

• Position the XL2 at the measurement location using a micro-

phone stand or a tripod.
• Select the SLMeter function in the measurement menu and
toggle with page to the numeric result page .

All wideband and RTA levels are measured and

logged simultaneously. You select which sound
levels should be displayed.
Press start to measure and display the
sound levels results indicated with ----.

34
 Sound Level Meter

Select Frequency Weighting Select Time Weighting

 The pop-up window FREQ WEIGHTING appears.  The pop-up window extends with TIME WEIGHTING.

• Select the frequency weighting A. • Select the required time weighting; e.g. (=Fast).

Installation of the Extended Acoustic Option

adds more items to the pop-up window

• Confirm with enter . • Confirm with enter .

35
 Sound Level Meter

Select Parameter Select Correction Value

 The pop-up window extends with PARAMETER settings.  The pop-up window extends with CORRECTION settings.

• Select the parameter live. • Select the parameter off.

• Confirm with enter .

• Confirm with enter .
 The pop-up window closes and the measured sound pres-
sure level LAF is displayed.

36
 Sound Level Meter

Select further Sound Levels Select Input Range

• Select the lowest possible input range based on the maxi-
mum level expected during the measurement. Wrong input
ranges are indicated by a “<” in front of the measurement
value or a flashing OVR message in the lower menu bar.
• Select the input range RNGE and press enter .
• Turn the rotary wheel to set the applicable input range and
confirm with enter .

The numeric result page and the real-time ana-

lyzer page use the same input range.

• Select further sound pressure levels as described above;

e.g., LAeq and LAFmax

37
 Sound Level Meter

Start Measurement Stop Measurement and Data Saving

• The XL2 is ready to measure the sound levels LAF, LAeq and • Press stop .
LAFmax.
• Press start .  The XL2 stores the broadband sound pressure levels and
the real-time analyzer results simultaneously.
 The run indication switches to running . The integrated
sound pressure level over time LAeq and the maximum lev-
el in the measurement period LAFmax are displayed. The
parameter RUN, LOG (logging is enabled) or AUD (audio
recording is configured) flashes in the memory menu.

• Press enter to confirm. The measurement data is stored

on the SD Card in ASCII format.

 The sound pressure level measurement is completed.

38
 Sound Level Meter

Data Post-Processing RTA Measurement - Getting Started

The XL2 stores all data and audio onto the SD card for direct
transfer to a computer. Audio data is stored as .wav files. Data Test Preparations
reports and log files are stored in plain text format, which can The XL2 reads the electronic data sheet of any connected ASD
be opened with any text editor (Notepad, Wordpad, etc.). The microphones provided by NTi Audio and switches the 48 V
data is tab-delimited, so dropping the .txt file into a spreadsheet phantom power automatically on as follows:
application will conveniently show the results in columns. • Connect the measurement microphone to the XL2.
• Switch on the XL2 .
Furthermore, a series of free MS Excel application templates pro-
vide a convenient way to view the measurement results of specific  The 48 V phantom power indication in the upper menu bar
tasks and create simple reports. They are available as free down- changes to ASD. The XL2 is ready for acoustic measure-
load for all registered XL2 customers on the support website at ments.
https://my.nti-audio.com. (Enable all macros when opening the
document.) • Position the XL2 at the measurement location using a micro-
phone stand or tripod.
For the most comprehensive analysis of logged noise monitor- • Select the SLMeter function in the measurement menu and
ing data, use the XL2 Data Explorer software. The data import toggle with page to the real-time analyzer (RTA) page
into the software is enabled by the Data Explorer Option, which .
needs to be installed in the XL2 Sound Level Meter. More de-
tails in chapter XL2 Data Explorer.

All wideband and RTA levels are measured and

logged simultaneously. You select the sound
levels to be displayed.

39
 Sound Level Meter

RTA Configuration Select RTA Frequency Weighting

The XL2 displays two different sound pressure levels at the
same time. You configure which test results to display; e.g.,  The pop-up window FREQ WEIGHTING appears.
LZFmax and LZFlive.
• Select the frequency weighting Z.
• Ensure no other measurement is going on. The run indication
should display the stop symbol .
• Select the LZF value with the rotary wheel .

• Confirm with enter .

Press start to measure and display the

sound levels results indicated with ----.
• Confirm with enter .

40
 Sound Level Meter

Select RTA Time Weighting Select Upper/Lower RTA Parameter

• Select the parameter shown to the right of the upper LZF
 The pop-up window extends with TIME WEIGHTING. value with the rotary wheel ; e.g. max.
• Press enter .
• Select the required time weighting; e.g., (=Fast).
 The pop-up window PARAMETER appears.

• Select the parameter max.

• Confirm with enter . • Confirm with enter .

• Follow the same instruction and select the lower RTA pa-
rameter live.

41
 Sound Level Meter

Select Input Range Start RTA Measurement

• Select the lowest possible input range according to the maxi- • The XL2 is ready to display the measured sound pressure
mum level expected during the measurement. Wrong input levels LZFmax and LZFlive.
ranges are indicated by a < in front of the measurement val- • Press start .
ue or a flashing OVR message in the lower menu bar.
• Select the input range RNGE and press enter .  The run indication switches to running . The actual sound
• Turn the rotary wheel to set the applicable input range and level LZFlive and the maximum level LAFmax are displayed.
confirm with enter . The parameter RUN , LOG (logging is enabled) or AUD (au-
dio recording is configured) flashes in the memory menu.

The numeric result page and the real-time ana-

lyzer page use the same input range.

42
 Sound Level Meter

Stop the Measurement and Data Saving Reporting

• Press stop .
A report saves the conducted measurements onto the installed
 The XL2 stores the broadband sound pressure levels and SD Card. The XL2 Supports setting the individual levels to be
the real-time analyzer results simultaneously. stored in the report after the measurement is completed.

2
3

• Press enter to confirm. The measurement data is stored 1 Add Spectra

on the SD Card in ASCII format.
No No RTA measurement reporting.
 The RTA measurement is completed.
Leq The RTA Leq level is stored in the report.

43
 Sound Level Meter

Leq, Lmax, The RTA Leq, Lmin, Lmax levels are stored Logging
Lmin in the report. The XL2 features a powerful sound level meter data logger,
which allows you to record all required sound level values dur-
All All RTA levels are stored in the report. ing the selected period of time. All results are logged onto the
SD Card. The measurement results can be loaded to a PC for
2 Report Values documentation and visualization. The LOG menu offers the de-
Choose between the following result reporting: tailed setup of the log report.

ALL Records all available sound pressure levels

without correction values.
1
Selected Records a subset of up to 10 different levels, 2
including correction values if you require. 3
4
• Select Report Values with the rotary wheel . 5
• Press enter to toggle between All or Selected.
6
7
3 Selected Report Values
• By setting Selected at 2 up to 10 individual report val-
ues can be chosen. Select the first value Lxx with the
rotary wheel and press enter .

 The pop-up window for level selection appears.

• Select the reporting level with the rotary wheel and

confirm with enter .

44
 Sound Level Meter

1 Logging 4 Log Audio

Select Logging with the rotary wheel and press enter The XL2 logs audio data as a wav-file. Choose among the
to enable the automated logging of test results. following settings:

On The XL2 logs measurement data every interval Off Audio logging is off
dt 2 .
On Audio logging is activate from mea-
Off No Logging surement start to stop.

2 Interval Dt Events Only Audio logging of triggered events

Adjust the logging interval. The optional Extended Acoustic only.
Pack offers the additional 100 ms logging.
For more details read the chapters Wav-File Recording and
3 Add Spectra Events.
Set the RTA logging for each logging interval here.
5 Format
No No RTA spectrum is logged. Choose among the following audio recording settings:

Leq The Leq spectrum is logged. Compressed Compressed audio logging

Leq, Lmax, The Leq, Lmax and Lmin spectrum is Compressed+AGC Compressed audio logging with
Lmin logged simulatenuously (requires optional automated gain control
Extended Acoustic Pack).
24Bit_48kHz Linear audio logging in 24 bit,
48 kHz resolution (optional with
Extended Acoustic Pack)

45
 Sound Level Meter

6 Log Value Setting Wav-File Recording

Choose between the following settings:
The XL2 records a wav-file of the measured input signal and
ALL Logs all available sound pressure levels with- stores it on the SD Card. The available formats are:
out correction values. • Compressed (default, using ADPCM compression). A new
wav-file is started automatically after 12 hours of recording
Selected Logs a subset of up to 10 different sound (typical maximum wav-file size = 512 MByte)
pressure levels, including correction values if • Compressed+AGC, compressed with automated gain con-
you require. trol. The gain control increases the level of low-level signals,
so that the wav-file is well-leveled during playback on the
• Select Log Values with the rotary wheel . PC.
• Press enter to toggle between All and Selected. • 24Bit_48kHz, linear wav-file logging in 24 bit, 48kHz resolu-
tion with the optional Extended Acoustic Pack. A new wav-
7 Selected Log Values file is started automatically after 1 hour of recording (typical
By setting Selected at 5 up to 10 individual log values can maximum wav-file size = 512 MByte)
be chosen.
• Select the first value Lxx with the rotary wheel and
press enter .
Broadcast Wave Format BWF
 The pop-up window for level selection appears. The XL2 stores scaling factor, serial number,
date, time and time zone within the wav-file (ac-
• Select the logging level with the rotary wheel and con- cording to EBU TECH 3285). This information is
firm with enter . available through professional audio/video tools
typically used in broadcast.
At 100ms Logging is the log value selection limited to five
different parameters.

46
 Sound Level Meter

Sample name of wav-file: The advantage of wav-file recordings is to identify and docu-
MyTest_SLM_000_Audio_FS133.0dB(PK)_00.wav ment sound sources after the measurement. For example, at
a live event an excessive peak level may have been measured
and logged. Actually, this peak level was caused by people
1 2 3 4 5 shouting nearby the measurement microphone, and not by the
audio system being monitored. The recorded wav-file assists in
1 MyTest verifying this and the test results can then be post-processed.
File name defined by user.

2 SLM Pausing Measurement

Measurement function. If any ongoing measurement is paused , the
XL2 continues the recording of wav-files during
3 000 the paused period. The logged data and audio
Automatically incrementing file number. data can be synchronized using the stored real-
time information.
4 Audio_FS133.0dB(PK)
Audio file with full scale peak level. In case of a Com- Events
pressed + AGC recording, the file name reads “AGC”; this The wav-files are stored in a folder, named, for
file contains corrected level information only. example,
2011-11-30_SLM_000_AudioEvent_0001-0200.
5 00 The actual wav-files are named for example, as
For wav-file recording over longer periods, the XL2 splits xxxx_FS133.0dB(PK).wav (xxxx = incrementing
the audio data into individual wav-files with about 500 MB number)
(compressed audio: 12 hours; linear: 1 hour), keeping the
file size small for easier handling on the PC. The number 5
increments for each successive wav-file.

47
 Sound Level Meter

Another example is environmental noise monitoring: Listening Select the lowest possible input range accord-
to the recorded wav-file after the measurement may help to ing to the maximum level expected during the
determine the predominant sound source. The XL2 Analyzer measurement; e.g., If the sound pressure will
preserves the original absolute test signal level in the recorded always be below 110 dBSPL, select the lowest
wav-file. input range 10 - 110 dBSPL.

The XL2 Analyzer provides three input ranges to accom-

modate the wide range of input signals. The dynamic range
of the recorded wav-file is set according to the selected in-
put range. For example, at a microphone sensitivity of
S= 20 mV/Pa, the full-scale peak level is:

Range Name Range Level Full-scale peak level

Low 10 - 110 dBSPL 117.8 dBSPL

Mid 30 - 130 dBSPL 135.9 dBSPL

High 50 - 150 dBSPL 159.9 dBSPL

48
 Sound Level Meter

Events (optional) Recommendation

With the large storage capacity of the XL2, NTi Audio recom-
The event function is available with the XL2 Extended Acoustic mends logging at a 1 second or faster interval. This allows the
Pack Option. The XL2 Analyzer may be configured to record accurate collection of event data; one event will be stored with-
wav-files and additional noise levels only when triggered, in- in a logged interval. If results for reporting are required at lon-
stead of the complete measurement duration. ger intervals, e.g. one hour, the XL2 Data Explorer software is
recommended. It easily combines logged data into longer audit
Advantages intervals. An additional advantage of a faster logging interval is
Reduces the data volume acquired, thereby that only an entire logged interval can be excluded from the
• Simplifying data post-processing average. This is useful when a qualified noise consultant judges
• Saving memory for long-term measurement applications. that a sound is not caused by the object under test or is not a
normal sound for a measurement location.
Events
Events are triggered either automatically by sound levels above/ Functions
below a preset value or manually by external key press using The XL2 event feature offers the following functionalities:
the XL2 Input Keypad. • Automated event triggered at noise levels above/below a
preset value including setting markers for specific noise cat-
egories. Application example: Recording the noise level for
Data Logging LAF > 80 dB.
The XL2 Analyzer logs the data specified in the • Event triggered by external key press of the XL2 Input Key-
LOG setting for the complete measurement du- pad. You can utilize four keys (1-4) to categorize any noise of
ration into a log file. The markers and triggered interest or noise to be later excluded in the post-processing.
events results are added to the same log file. A typical application is categorizing any annoying industrial
The XL2 Input Keypad is available as an acces- noise by persons living in the neighborhood.
sory. Please see chapter Options and Accesso-
ries for details.

49
 Sound Level Meter

Trigger Events: on level above/below

14

100 Event Duration

Level [dB]

90 1
2 13
3 12
2 80
4
14
3 70
5
13 12 6
60 7

8
Time [seconds] 9
11
10

Features:
• The levels LAeq, LZeq and LCPeak are recorded for the event
duration.
• Audio data is recorded for the triggered event duration only,
thus simplifying data post-processing and saving memory
space for long-term measurements.
• Setting markers by external key press of the XL2 Input Key-
pad.

50
 Sound Level Meter

1 Trigger Events 3 Stop [dB]

Choose from the following settings: Set the level at which the triggered event is stopped.

Off No event triggering on level Stop level = Start level 2 - Hysteresis 14

above
on level Events are triggered at noise levels above the
above preset value 2 for the start duration 13 . on level Stop level = Start level 2 + Hysteresis 14
below
on level Events are triggered at noise levels below the
below preset value 2 for the start duration 13 . Stop Duration 12
The event stop is triggered when the noise level is lower (or
on ext. Events are triggered by external key press. higher) than the preset value and continues for the preset
key duration.
press
Hysteresis 14
2 Start [dB] Set the hysteresis to an appropriate value to prevent rapid
Set the level at which the triggered event is started. switching on and off as the level drifts around the Start
level.
Start Duration 13
The event start is triggered when the noise level is higher 4 Level Selection
(or lower) than the preset value and continues for the pre- Define the level type to be monitored.
set duration.

51
 Sound Level Meter

5 Log Audio 7 Audio Logging Period

The XL2 logs audio data as a wav-file. Choose from the fol- If Log Audio 5 is set to Events Only, then the duration
lowing settings: for the audio recording may be further specified:

Off Audio logging is off Recording Records a wav-file for the whole trig-
whole event gered event duration.
On Audio logging is activated from
measurement start to stop. Stop recording Records a wav-file for the specified
after period after the event start is trig-
Events Only Audio logging of triggered events gered.
only.
8 Status Information
For more details read the chapter Wav-File Recording. Displays current trigger status:
• Waiting for trigger
6 Format • Armed (during start duration 13 )
Choose from the following audio recording formats: • Audio + data recording
• Completing log cycle
Compressed Compressed audio logging
9 Actual Level
Compressed+AGC Compressed audio logging with Measurement result of the defined level 4 .
Automated Gain Control (AGC)
10 Event Counter
24Bit_48kHz Linear audio logging in 24 bit, Counts the number of triggered events that have occurred
48 kHz resolution. (Required for during the ongoing measurement.
post-processing on the PC with
Extended Acoustic Pack)

52
 Sound Level Meter

11 Trigger and Marker Monitor Trigger Events: on external key press

Answers the question: What caused the triggered event? Trigger Events by pressing a button on the external input key-
pad with automated or manual stop of the event.
Lvl Event automatically triggered by level.
100 Event Duration Event Duration

Level [dB]
1 Event triggered or marker added by pressing key 1
of the XL2 Input Keypad. 90

2 Event triggered or marker added by pressing key 2

80
of the XL2 Input Keypad.

70
3 Event triggered or marker added by pressing key 3
of the XL2 Input Keypad. 15 15

key press

key press
60

4 Event triggered or marker added by pressing key 4

of the XL2 Input Keypad.
Time [seconds]

12 Stop Duration
See 3 .
Features:
13 Start Duration • The levels LAeq, LZeq and LCPeak are recorded for the event
See 2 . duration.
• Audio data may be recorded for the user-defined event dura-
14 Hysteresis tion 15 after the key press.
See 3 . • Retrigger with every repeated key press within the event
duration.

53
 Sound Level Meter

15 Event Stop Mode and Event Duration

on key release The event is recorded as long as the

button of the input keypad is kept
pressed; the Event period is at least
Min. Event Duration long.

15 on ext. key- The event is stopped by pressing a but-

press ton on the external input keypad; the
16
Event period is at most Max. Event
Duration long.

16 Button Functionality of Input Keypad

treat each key All four buttons operate individually.

separately For example pressing the button 2
will be recorded as button 2 in the
measurement report. This allows you
to distinguish different acoustic noise
sources.

treat all keys as All four buttons operate in parallel and

Key 1 any button press will be recorded as
button 1 in the measurement report.

54
 Sound Level Meter

How to Setup the XL2 for Triggered Event Measurements Logging Enabled
• Select the logging page, set Logging On, Interval dt: Triggered-event recording requires the activa-
00:00:01 and choose the required log values. tion of sound level logging. Using the default
• Setup the event page. For example, the screenshot below Interval dt: 1 second is recommended.
starts the event recording after LAF exceeds 80 dB for 2 sec-
onds and stops after LAF is lower than 70 dB for 3 seconds. Auto Save
If Log Audio 5 is set to Events Only, then
the XL2 sets per default Naming+Saving: auto
in the memory menu. This ensures that the re-
corded triggered event data is stored on the SD
Card.
For convenience, in case more than 20 triggered
events have been recorded, the Autosave ->
Delete function is disabled, as deleting such
multiple wav-files on the XL2 is time-consum-
ing.

Wav-files
All triggered-event wav-files are stored in an in-
dividual folder. For details see chapter Logging.

• Select the memory menu and create a new folder. This folder
will then be displayed in the memory menu. All log data and
event wav-files are stored in this folder.

 The XL2 is ready for the triggered event measurement.

55
 Sound Level Meter

Limits 1 Limit LED On/Off

Select Limit LED with the rotary wheel and press enter
The limit page offers two functions: to enable/disable the limit function.
• Setup of limit LED function; enabling the XL2 to highlight
any sound levels that exceed the pre-set limit in orange or 2 LED - Level 1
red color. The default color is green. Select one sound level for the limit LED indication .
• Limit parameter setup for external connected accessories, • Select the sound level field with the rotary wheel .
such as the Digital I/O Adapter PCB, the Limit Light or the • Press enter and select the sound level for the limit
Stack Light. These accessories connect to the digital I/O in- LED indication.
terface of the XL2.
3 Selected Level Values
To set the level values for the limit LED ,
• Select the Red or Orange sound level with the rotary
1
wheel and press enter .
2 8
• Set the level value with the rotary wheel and confirm
3
with enter .

4 Digital I/O On/Off

4
Select Digital I/O with the rotary wheel and press enter
5 7 to enable/disable the operation of externally connected
accessories.
6

56
 Sound Level Meter

5 I/O - Level 1
Setup of the level type 1, which is used to trigger externally I/O Limits with Triggered Events
connected accessories. If event recording is enabled, the digital output
• Select the level field with the rotary wheel . 4 (Out 4) is utilized, e.g. as confirmation feed-
• Press enter and select the level for the control of the back to the XL2 Input Keypad. Therefore the
external accessory. limit setting of Out 4 is disabled.

6 Selected Sound Level Values

To set the level values for the control of the externally con-
nected accessory.
• Select the Out 1, Out 2, Out 3 or Out 4 level with the ro-
tary wheel and press enter . The Limit Light and the
Stack Light use Out 1 for red, Out 2 for yellow and Out
3 for green light.
• Set the level value with the rotary wheel and confirm
with enter .

7 I/O - Level 2
Follow the setting for I/O - Level 1. The I/O level 1 may be
combined with I/O level 2 using and/or combinations, pro-
viding indications in level ranges. Alternatively, other levels
can be selected for the control of the externally connected
accessories.

8 LED - Level 2
Follow the setting for LED - Level 1.

57
 Sound Level Meter

Correction Value KSET 1

The correction value page offers a measurement wizard for live

event monitoring, applicable in case the measurement location
differs from the loudest position in the live event area. 2

Measurement Position
The goal at live event monitoring is to measure the sound level
at the loudest position accessible by the audience. Setting up
any sound level measurement at this loudest location is typi-
cally not practical, thus an alternative measurement position is
chosen. The recommended measurement position in order to
minimize the influence that audience noise has on the mea-
surement:
• Mount the measurement microphone in front of the main
speakers
• Position the XL2 Analyzer at front of house (FOH) 1 Correction k1
• Connect the XL2 Analyzer and measurement microphone The correction k1 is based on the LAeq.
using a professional audio cable
2 Correction k2
Select the level type for correction k2.
Positioning the measurement microphone at
front of house (FOH) may result in audience LCpeak for Germany DIN15905-5;
noise interfering with the measurement results. correction is based on LCpeak measurement
The audience noise will be further amplified by
the measured k-values. LCeq correction is based on LCeq measurement

58
 Sound Level Meter

Level Difference How to Measure the Correction Value

Prior to the start of the live event, the level difference between • Play a Pink noise signal at the typical sound level of the live
the loudest and the measurement position is measured. The event (signal source: Minirator or NTi Audio Test CD or or
XL2 Analyzer calculates the level difference automatically based USB Flash Drive)
on the individual sound level measurements at both locations. • Select the correction page .
This level difference is included in the sound level reading dur- • Search the audience area for the location with the highest
ing the live event, and the XL2 thereby displays and records the sound pressure level and position the XL2 Analyzer.
sound pressure level of the loudest point. • Turn the rotary wheel to select the parameter RUN next
to Audience, select LA, LC or LA&LC and press enter .

Measurement
Position
(Microphone)

Level difference

Loudest
audience area
Audience
Position

XL2 positioned at FOH  The XL2 measures the sound level at the loudest position
for 15 seconds. The timer counts down to zero.

59
 Sound Level Meter

• Wait until the measurement is completed. • Wait until the measurement is completed.
• Position the XL2 at the measurement position. • The correction values k1 and k2 are calculated and displayed
• Turn the rotary wheel to select the parameter RUN next including date and time.
to Measure, select LA, LC or LA&LC and press enter .

 The XL2 measures the sound level at the measurement

position for 15 seconds. The timer counts down to zero.

60
 Sound Level Meter

Manual Setting of Correction Values • Set the correction value with the rotary wheel .
You may fine-tune the correction values k1 and k2 manually.
Such fine-tuning adds the remark “Manually Adjusted” in the  The note “Manually Adjusted” is displayed at 2 .
log file.
• To undo the manual setting turn the rotary wheel to select
the parameter UNDO at 2 .
• Confirm with enter .

Reset Correction Values

You may clear all correction values back to zero
by pressing the Clear All 1 and confirm with
enter .
3
1 2 Display k1 and k2 during Measurement
The correction values k1 and k2 can be dis-
played in the numeric result page during the on-
going sound level measurement instead of any
other sound levels.

• Turn the rotary wheel to select the correction value 3 Correction Values in Profiles
and press enter . The correction values k1 and k2 can optionally
be stored within profiles. Loading the profile,
 The selected correction value starts flashing. sets the stored correction values.

61
 Sound Level Meter

Locked Run Mode

• The page button allows toggling between the sound lev-
The Locked Run Mode simplifies sound level monitoring. You el meter and real time analyzer window. All other buttons are
just need to power up the XL2 and the measurement starts deactivated during Locked Run Mode.
automatically. The measurement continues until you switch off
the instrument using the power button . The measurement
data is stored by default.

Start Locked Run Mode

• Set the required parameters in the sound level meter for
your noise monitoring application.
• Press and hold the start/stop button for 3 seconds.

 The Locked Run Mode is now activated. The Run Indicator

1 displays L. The Info window is displayed at the same 1
time.

• Switch off the instrument.

 The measurement is stopped and the data is saved. End Locked Run Mode
• Press and hold the start/stop button for 3 seconds during
• Switch on the instrument. the ongoing measurement.

 The sound level measurement starts automatically and  The measurement is stopped and the Locked Run Mode
continues as long as the device is powered on. deactivated.

62
Sound Level Meter

63
 FFT Analysis + Tolerance

5. Acoustic Analyzer FFT Analysis + Tolerance

Besides the comprehensive sound level meter functions, the The FFT measurement is the ideal tool for visualization of comb
XL2 Audio and Acoustic Analyzer offers the following acoustic filters and narrow band effects. It allows a detailed frequency
measurement functions: response investigation of audio and acoustic systems. The XL2
includes an extremely fast, real-time FFT. Optional features
• FFT Analysis with optional tolerance function are
• Reverberation Time • High-resolution Zoom-FFT up to 0.4 Hz steps in the fre-
• Polarity quency range 5 Hz - 20 kHz provided with optional Extended
• Delay time Acoustic Pack or the Spectral Limits Option
• 1/12 Octave + Tolerance Analysis (optional) • Capture and tolerance function provided with Spectral Limits
• Noise Curves (optional) Option; thus the main menu function reads FFT + Tol.
• Speech intelligibility STIPA (optional)

64
 FFT Analysis + Tolerance

1 Result Symbols / Capture & Start Tolerance Mode

This field offers two functions:
• Symbols for measurement results 2

14 13 12 Upper result displayed as line.

Lower result displayed as bargraph.

11
1
10
2 • Capture & Start Tolerance Mode
The displayed readings may be captured as reference
3 reading C1 to C8 for
• Comparing measurement results against captured
4 traces with relative or absolute curve display.
• Creating tolerance masks based on captured refer-
ence curves for passed / failed measurements.

9
8
Capture EQ Captures the upper parameter

5 6 7 Capture Live Captures the lower parameter

65
 FFT Analysis + Tolerance

Manage Allows to rename captures, clear re- 3 Y-Scale setting

captures corded captures, save captures to the • Select the Y-Axis with the rotary wheel and confirm
SD Card for export from the XL2 or with enter .
load captures from the SD Card for im- • Select the zoom factor between 20, 10, 5, 2.5 dB/div
port to the XL2. and confirm with enter .
• Scroll up and down with the rotary wheel to select the
Start tolerance Starts the tolerance mode for passed/ Y-axis range.
mode failed measurements comparing the • Confirm with enter .
actual measurement results against a
tolerance band. 4 Measurement Result
Displays the actual and averaged measurement results.
2 Measurement Result
Actual level result of the indicated frequency band. The cur- 5 Input Range
sor readout displays the center frequency and the level of The XL2 Analyzer provides three input ranges to accom-
the band indicated by the arrow. modate the wide range of input signals. The individual rang-
es are based on the microphone sensitivity setting in the
Upper parameter displayed as line. calibration menu of the XL2. For example at a sensitivity
S=20mV/Pa the input ranges are
Lower parameter displayed as bargraph. • Lower range: 10 - 110 dBSPL
• Middle range: 30 - 130 dBSPL
• Upper range: 50 - 150 dBSPL

Select the lowest possible input range according to the

maximum level expected during the measurement; e.g., if
the sound pressure will be always below 110 dBSPL, then
select the lowest input range 10 - 110 dBSPL.

66
 FFT Analysis + Tolerance

6 Time Weighting 8 Actual Measurement Time

Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 sec- Counts actual measurement time in hrs:min:sec. Supports
ond as well FAST (125 ms) and SLOW (1 second). Applica- setting of time modes: continuous and single.
tions:
Timer Mode Continuous
Short Time High-resolution in time with minimum (applicable for standard measurements)
Weighting averaging All values are recorded and monitored continu-
ously after starting a measurement with start .
Long Time Low resolution in time with longer aver- The actual measurement time is shown.
Weighting aging
Timer Mode Single
7 Run Indication Automatically stops the measurement after the
The run indication shows the measurement status running, pre-set measurement time.
paused or stopped. Various measurement settings are • Set the required measurement time.
locked during ongoing measurements, such as changing • Start the measurement .
the input ranging or the preset measurement time.
For passed/failed measurements with the Spectral Limits 9 Preset Measurement Time
option the run indication may display A for a preset auto- Adjustment of preset measurement time for single timer
mated level trigger. setting.

67
 FFT Analysis + Tolerance

10 Readout Frequency 11 Zoom Mode

You may select any frequency to read out individual levels. (optional, applicable with the Extended Acoustic Pack or
The selected frequency is indicated by the cursor arrow. the Spectral Limits Option)
Choose between the following settings:
• Select the readout frequency 10 and press enter .
The cursor follows automatically the highest level, • The zoom mode is displayed above the flashing arrow.
e.g. tracing feedback frequencies at live sound. • Select the zoom-in frequency with the rotary wheel .
• Select the frequency with the rotary wheel . • Press limit and zoom the linear frequency scale in or
• Press enter . out with the rotary wheel .
• You may readout any individual frequency. • Release limit and scroll the linear frequency scale left
• Return to auto frequency with enter . or right with the rotary wheel .

 The cursor returns to the frequency with high- 12 Phantom Power Supply
est level bar.
48V The XL2 provides 48 V Phantom power supply
The cursor readout may be set manually to any to the connection microphone or sensor.
frequency. The readout remains at the selected fre-
quency. ASD An NTi Audio measurement microphone with
• Select the frequency with the rotary wheel . automated sensor detection ASD is connect-
• Press enter . ed. The XL2 reads the electronic data sheet of
• Select the frequency of interest. the microphone and switches the 48 V Phan-
• Confirm with enter . tom power automatically on

 The cursor readout 2 displays the measure- 48V Phantom power is switched off.
ment results of the selected frequency band.

68
 FFT Analysis + Tolerance

13 Measurement Unit 14 Page Selector X-Scale and Parameter Setting

Select the measurement unit as follows:
20k Shows FFT result of the frequency band range.
dB Sound level in dBSPL 484.38 Hz - 20.453 kHz in a resolution of
This measurement unit is permanently selected 140.62 Hz with 143 bins shown on the display.
upon connecting a NTi Audio measurement mi-
crophone with electronic data sheet. 1k7 Shows FFT result of the frequency band range.
58 Hz - 1.722 kHz in a resolution of 11.72 Hz with
dBu Input level in dBu 143 bins shown on the display.

dBV Input level in dBV 200 Shows FFT result of the frequency band range.
7 Hz - 215.01 Hz in a resolution of 1.46 Hz with 143
V Input level in Volt bins shown on the display.

Usr User Range

(applicable with optional Extended Acoustic Pack
or Spectral Limits Option)
5 Hz - 20 kHz in zoom mode with a minimum reso-
lution of 0.366 Hz and 143 bins displayed.

Set Selection for FFT Windowing:

• Hann: Default for acoustic measurements
• Dolph-Chebyshev: for analyzing small signals
(e.g. harmonics) close to a dominant signal.

The page button switches these display modes.

69
 FFT Analysis + Tolerance

FFT Analysis - Getting Started Configuration

The XL2 displays two different sound pressure levels at the
Test Preparations same time. You configure to display either the levels Live,
• Connect the measurement microphone to the XL2. Max, Min, EQ or captured results.
• Switch on the XL2 .
• Select the upper result parameter with the rotary wheel .
 The 48 V Phantom power indication in the upper menu bar
changes to ASD. The XL2 is ready for acoustic measure-
ments.

• Position the XL2 at the measurement location using a micro-

phone stand or tripod.

• Confirm with enter .

70
 FFT Analysis + Tolerance

Select Upper/Lower Reading

 The pop-up window Select reading appears.  The pop-up window Select reading mode appears.

• Select the integrated averaged reading EQ. All available se-

lections are Z-weighted (= no weighting).

• Select EQ for normal absolute display of measurements.

• Follow the same instruction and select the lower FFT read-
ing Live.

• Confirm with enter .

Press start to measure and display the
sound levels results indicated with ----.

71
 FFT Analysis + Tolerance

Select Input Range Start Measurement

• Select the lowest possible input range according to the maxi- • The XL2 measures the selected sound pressure lev-
mum level expected during the measurement. els Live and EQ. All available sound levels are
• Select the input range RNGE and press enter . Z-weighted (= no weighting).
• Turn the rotary wheel to set the applicable input range and • Press start .
confirm with enter .
 The run indication switches to running . The actual sound
level Live and the averaged level EQ are displayed. The pa-
rameter RUN flashes in the memory menu.

72
 FFT Analysis + Tolerance

Stop Measurement and Data Saving Audio Recording

• Press stop . The XL2 Analyzer may record a linear audio file (48 kHz, 24 Bit)
of the measurement period together with the FFT data. Just
 The XL2 stores the measurement data automatically. load a txt-file named “fftaudio.txt” in the root directory of the
XL2. This requires the installed option Extend Acoustic Pack.

Capture References and Create Tolerances

The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.

Features:
• Captures multiple traces in the internal memory
• Comparing measurement results against captured traces
with relative or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captured reference
curves for passed / failed measurements
• Export and import of tolerance and capture files
• True peak level in 1/1 and 1/3 octave resolution
• Press enter to confirm. The measurement data is stored • High-resolution Zoom-FFT up to 0.4 Hz steps in the frequen-
on the SD Card in ASCII format. cy range 5 Hz - 20 kHz

 The measurement is completed. Read the detailed description in the separate chapter
Capture + Tolerance.

73
 Reverberation Time RT60

Reverberation Time In detail, the reverberation time is based on a linear least-

squares regression of the measured decay curve. If the
The XL2 measures the energy decay from 63 Hz to overall reverberation time is short (e.g. < 0.3 seconds)
8 kHz using the Schroeder method in 1/1 octave resolution. The the room acoustic is referred to as being “dead”; for ex-
optional Extended Acoustic Pack enables 1/3 octave band reso- ample, a heavily furnished room with thick carpets, cur-
lution from 50 Hz to 10 kHz. Use either an impulse source (e.g., tains and upholstered furniture may have such an acous-
a starter pistol) or an interrupted pink noise as the test signal. tic character. If the overall reverberation time is long (e.g. >
2 seconds) the room acoustic is referred to as being “live” and
What is Reverberation Time? echoic; for example, a large empty room with painted plaster
Reverberation time is the time required for the sound pres- walls and a tiled floor may have such an acoustic character.
sure level to decrease by 60 dB after the sound stimulus signal
Level [dB]
is stopped. For simple practical measurements the applicable
standard ISO 3382 and ASTM E2235 specifies the following
0 dB
two measurement methods:

-5 dB
• T20
- The measurement requires just a small dynamic measure- 20 dB level range to
ment range of ~35 dB above the ambient noise level for obtain the reverbera-
distance to tion time
each frequency band. noise floor
- RT60 (T20) = 3 x decay time of 20 dB
• T30 -25 dB
- The measurement requires a dynamic measurement
range of ~45 dB above the ambient noise level for each
frequency band. -35 dB
Time
- RT60 (T30) = 2 x decay time of 30 dB
Reverberation Time Measurement with T20 method

74
 Reverberation Time RT60

RT60 Run Test Page RT60 Result Page

12 11

10 18
1
9 17
8
13

14

7 15

6
16

2 5
4

75
 Reverberation Time RT60

RT60 Cycle Result Page 1 Set Level Markers

Prior to conducting a reverberation time measurement, the
environmental noise is measured, and the required energy
level of the test signal is determined.

• Select SET and press enter to measure the actual en-

vironmental noise.
22
 The required level markers appear in grey color.

21 2 Input Range
19 Select between the lower, mid and upper input range. The
exact ranges depend on the microphone sensitivity setting
in the calibration menu of the XL2.
20
3 Run Indication
This icon displays the running and stop status of the rever-
beration time measurement. It is controlled by start/stop
.

76
 Reverberation Time RT60

4 Measurement Status STAT 6 Actual Real-Time Spectrum

Displays the actual measurement status. Start and stop the The black bars indicate the actual signal, including back-
reverberation time measurement with start/stop . The ground noise. While setting up the reverberation time mea-
following status information is displayed: surement you should increase the test signal level until the
black bars exceed the grey bars completely and the status
ARMED Measurement is waiting for the test signal 4 displays NOISE.
to exceed at least one measurement trigger
marker, then the measurement is triggered 7 Level Marker
automatically. The grey bars indicate the signal level required for effective
reverberation time measurements in each octave band.
NOISE A sound stimulus signal above the trigger The marker has a length of 35 dB, and can be set by
marker is being received. • Selecting SET 1 with the rotary wheel .
• Press enter to measure the environmental noise in
DECAY Decay is being measured. the silent room.

PAUSE The measurement has been paused by press- 8 Band Status

ing pause . Indicates a successful reverberation time measurement
above each octave band with a tick .
STOP No Reverberation time measurement is pres-
ently being performed. 9 Measurement Method
Select between the measurement methods T20 and T30.
5 Average AVRG T20 requires just a small dynamic measurement range of
Counts the measurement cycles. When using an interrupt- ~35 dB above the ambient noise level for each frequen-
ed noise test signal, a minimum of 3 sequential cycles is cy band. T30 requires a dynamic measurement range of
recommended. ~45 dB.

77
 Reverberation Time RT60

10 Measurement Resolution 12 Page Selector

Reverberation time measurement selectable in 1/3 oc- Select between the RT60 run test page and the result page.
tave or 1/1 octave band resolution. The optional Extended The page button toggles between these displays.
Acoustic Pack enables 1/3 octave band resolution from
50 Hz to 10 kHz. RT60 run test page

11 Phantom Power Supply

RT60 result page. Toggle with the measurement
48V The XL2 provides 48 V Phantom power supply result selection 18 among
to the connection microphone or sensor.
AVRG RT60 result page showing average
ASD An NTi Audio measurement microphone with of all cycles and uncertainty factor
automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of CYC xx RT60 result page for each cycle
the microphone and switches the 48 V Phan-
tom power automatically on Last RT60 result page for last cycle

48V Phantom power is switched off.

14 Y-Axis Reverberation Time
Reverberation time in seconds. The scaling is automatically
adjusted.

78
 Reverberation Time RT60

14 Uncertainty Factor 18 Measurement Result Selection

The uncertainty factor is displayed in the RT60 average re- The reverberation time measurement function allows con-
sult page. It indicates the uncertainty of the averaged mea- secutive measurements within one test sequence. An
surement results, reduces as more cycles are measured, averaged test result of all measurements is automatically
and depends on the measured reverberation time and the calculated.
bandwidth of the individual frequency band; lower bands
show a higher uncertainty factor. The number of measure- Select CYC and scroll with the rotary wheel through the
ment cycles is displayed at 5 . individual test result cycles showing

15 Overall Reverberation Time Test Result Last Last Test Result

Readout of reverberation time and uncertainty factor. Displays the result of last measurement cycle.

Uncertainty factor. For more details see 14 . xx Single Test Cycle Results
The individual single test results are marked
Reverberation time measurement results. with CYC xx, where xx is an incriminating num-
ber. You may delete individual test results. The
16 X-Axis averaged reverberation time result uses only the
Octave Bands 63 Hz - 8 kHz remaining valid measurements. To delete results
in a cycle,
17 Cursor Readout • Select DEL with the rotary wheel
Select the individual frequency band and read out the fol- • Confirm with enter .
lowing numeric measurement results
• Uncertainty factor in % or correlation in %. AVRG Averaged Test Result
• Reverberation time RT60 (T20), of the selected frequen- The averaged test results of all cycles are calcu-
cy band, in seconds (s). lated and displayed.

79
 Reverberation Time RT60

19 Correlation Factor in % Test Signals

The correlation factor is 100% for perfectly linear sound Use either an interrupted pink noise or an im-
pressure level decay after the sound source has ceased. pulse source as the test signal.
The natural deviation from this linearity results in lower
correlation values. The correlation factor is typically 80 - • Interrupted pink noise
100%. Precision measurements require an omni-di-
rectional speaker with identical radiation char-
20 Cycle Reverberation Time Test Result acteristic in all directions. Various interrupted
Readout of cycle reverberation time and correlation factor pink noise test signals with different on/off
19 when selection 18 is CYC xx or Last. times are offered on the NTi Audio Test CD
or USB Flash Drive (included with the XL2) or
Correlation Factor. Scale is on the right Y-axis. For the Minirator signal generator. Test signals are
more details see 19 . available for download at https://my.nti-audio.
com/support/xl2. A minimum of three mea-
Reverberation time measurement result of individ- surement cycles shall be performed. The XL2
ual displayed cycle. Scale is on the left Y-axis. averages these readings automatically.

21 Y-Axis Correlation Factor • Impulse

The right Y-axis shows the correlation factor in %. The cor- The trigger signal is an impulse source, such
relation factor Y-axis is displayed when test result selection as a starter pistol, starter clap or bursting bal-
18 is CYC xx or Last. loon. Individual measurements, or test se-
quences with repeated trigger signals, can be
22 Delete Cycle Results carried out.
Individual cycle results may be deleted, thereby excluding
them from the calculation of the AVRG result.

80
 Reverberation Time RT60

RT60 Measurement - Getting Started Test Preparations

The XL2 reads the electronic data sheet of any connected ASD
Test Signal: Pink Noise microphones provided by NTi Audio and switches the 48 V
Play a pink noise signal through an omnidirectional speaker Phantom power automatically on as follows:
in the room under test. The sound source should be played
for a long enough time period to ensure that a balance be- • Connect the measurement microphone to the XL2.
tween injected and absorbed acoustic energy has been • Switch on the XL2 .
reached. For example the sound reflections should be given
enough time to reach all reflective surfaces in the room. As  The 48 V Phantom power indication in the upper menu bar
a rule of thumb, ensure that the pink noise is played for at changes to ASD. The XL2 is ready for acoustic measure-
least the time period of the estimated reverberation time ments.
test result. If in doubt, play the Minirator MR-PRO, the Test
Signal CD or or USB Flash Drive as sound source for at least • Position the XL2 at the measurement location using a micro-
5 seconds for each cycle. Each time the source signal stops, phone stand or tripod.
the XL2 recognizes this interruption, triggers, measures the • Select the RT60 function in the measurement menu and
decay time and calculates the reverberation time automatically. toggle with page to the run page RUN.
A minimum of three measurement cycles shall be performed. • Prepare the environment for the measurement. For example
mute all sound sources to establish silence.
Test Signal: Impulse
Fire an impulse sound source in the room under test, e.g. use
a starter pistol, starter clap or bursting balloon. The XL2 mea-
sures the decay time and calculates the reverberation time au-
tomatically.

81
 Reverberation Time RT60

Set Level Markers Get Ready for the Reverberation Time Measurement
• Select the parameter SET with the rotary wheel and • Protect the ears against high sound pressure levels, as the
press enter . test signals might be very loud.

 The environmental noise is measured and the grey level Setting the pink noise level:
markers are set. • Start the pink noise test signal with the appropriate on/off
time according to the room. Use an initial low level.
• Increase the test signal level until all level markers for the
minimum test signal level are passed. Use an equalizer to
push individual band levels.
• Switch off the interrupted pink noise signal after you have
finished setting the pink noise level.

82
 Reverberation Time RT60

Start the Measurement Continue the Measurement

• Press start . The status indication switches to ARMED. Using pink noise:
• Enable the test signal; e.g., switch on the interrupted pink The interrupted pink noise test signal continues with the pre-
noise signal or fire a starter pistol. set on/off time. The XL2 automatically triggers at each cycle.
• The black bars have to exceed the grey bars completely. Complete a minimum of three test cycles to accurately calcu-
late the uncertainty factor. Perform more cycles to increase the
measurement accuracy (= smaller uncertainty factor).

Using an impulse source:

A single impulse at one measurement location is sufficient. No
further measurements are required to increase the statistical
measurement accuracy.

Confirmation marks indicating success-

ful measurements, are displayed above each
band.

83
 Reverberation Time RT60

Stop the Measurement and Read Out the Result Read Out the Individual Cycle Result
• Press stop . • If multiple cycles have been recorded, then select CYC with
• If applicable, switch off the pink noise test signal. the rotary wheel , press enter and select the individual
• Select the result page RES with page . cycle result with the rotary wheel .

The average reverberation time for each fre- Within each cycle, the reverberation time for
quency band is displayed in seconds and the each frequency band is displayed in seconds
measurement uncertainty in %. and the correlation factor in %.

•
•
•
•
•
•
•
•
• •
• •
• •
• •

 The reverberation time measurement is completed.

84
 Reverberation Time RT60

Measurements with multiple source and microphone posi- Error Indications

tions Various error indications are displayed for unsuccessful rever-
beration time measurements. Corrupt cycles can be deleted
Room resonances may be applicable at individual measure- individually. These results are then excluded from the average
ment positions. Thus, perform reverberation time measure- calculations.
ments at further positions within the room and average all
readings. • LOW LEVL
This is the abbreviation of “low test signal level” during the
measurement. Increase the test signal level until the black
Overload Indication level markers exceed the grey level markers in every fre-
quency band. Also, ensure that the level falls below the grey
In case the measurement result exceeds the preset measure- level markers, otherwise use a reverberation time test signal
ment range, then limit arrows indicate this overload condi- with longer on/off times.
tion.
• T>18S
Possible causes for exceeding measurement ranges are The measured reverberation time exceeds the time limit of
• The measured sound pressure level exceeds the pre-set 18 seconds. This is commonly caused by either an incorrect
measurement range -> select the next higher measurement analyzer range setting or environmental noise. In the first
range or reduce the input signal level as applicable. case, choose another range setting. In the second case, en-
• The input level is near the maximum level of the connected sure that the environmental noise remains constant during
NTi Audio measurement microphone. the measurement, and/or SET the level markers again while
the environmental noise is high.
In case the level cannot be reduced (e.g. using a gun as signal
source) then the overload condition can be skipped by storing
a text-file with the filename “RT60allowOVLD.txt” on the XL2
main directory.

85
 Polarity

Polarity Positive/Negative Result Page

Polarity measurement is important in matching the left and

right speakers for a good stereo sound image. The polarity
function measures the polarity of cables, single speakers and
speaker cabinets. For testing, use the polarity signal provided
on the Minirator test signal generator, the NTi Audio Test CD or
USB Flash Drive. 4
The polarity of individual speakers or speaker cabinets might 1
change with the frequency. For example, the mid-range speak-
3
er polarity may differ from the woofer polarity within the same
speaker cabinet. Therefore, the polarity detailed result page of
the XL2 displays the measured polarity of the individual octave
bands from 125 Hz to 8 kHz. This allows in-depth verification of 2
the polarity - frequency relationship.

• Polarity is a simple test within the very com-

plex science of signal phasing. Drivers, speak-
ers and crossovers all cause phase shifts of
the audio signal.
• The polarity of various speakers within the
same cabinet may differ by design!
• Polarity testing is useful for checking the cor-
rect wiring of similar speaker systems.

86
 Polarity

Detailed Result Page 1 Input Selection

Select the signal source as follows:
• Select Signal Source with the rotary wheel .
• Press enter to select either

Voice Use the internal voice note microphone of the

Note XL2 for polarity measurements. This selection
Mic disables the rear speaker.
5
XLR Measure the acoustic polarity with a measure-
10 Input ment microphone. Alternatively, measure the
6
polarity of an electrical signal connected with
9 an XLR audio cable.

8
RCA Measure the polarity of an electrical signal con-
Input nected with an RCA audio cable.

7 2 Polarity Test Result

Displays either POSITIVE, NEGATIVE or ??? (=undefined).
For further visual indication, the limit button illuminates
Polarity result for Minirator
connected directly to XL2 Analyzer green for POSITIVE and red for NEGATIVE polarity.

3 Level RMS
Measures the absolute level of the input signal. The unit’s
dBu, dBV and V are selectable.

87
 Polarity

4 Balance Indicator 7 X-Axis

Indication of the audio signal balance between pin 2 and 3 Seven octave bands with center frequencies from
on the XLR input for input signals > -34 dBu. 125 Hz to 8 kHz. SUB displays the polarity of Sub-woofers;
frequency range < 100 Hz.
The input signal is balanced.

The signal is unbalanced. The level of pin 2 is 8 Negative Polarity Area

higher than pin 3. Measurement results area with negative polarity (-). The
The signal is unbalanced. The level of pin 3 is black line in the middle of relative level indicator 5 displays
higher than pin 2. the measured polarity of the individual frequency band. The
dashed line indicates the lower limit of the measurement
5 Relative Level Indicator result area.
The grey area shows the measured signal energy within
the individual frequency bands. The bands with the biggest 9 Uncertain Polarity Area ???
energy have the most effect on the actual displayed POSI- Polarity results for frequency bands in this area are uncer-
TIVE / NEGATIVE polarity result. tain. Therefore, the polarity result ??? is displayed.

6 Polarity Indication 10 Positive Polarity Area

Measurement results area with positive polarity (+). The
+ Polarity of frequency band is positive. The polarity re- black line in the middle of relative level indicator 5 displays
sult is in the upper display area; the + area. the measured polarity of the individual frequency band. The
dashed line indicates the upper limit of the measurement
- Polarity of frequency band is negative. The polarity result area.
result is in the lower display area; the - area.

88
 Polarity

Polarity Measurement - Getting Started

For acoustic polarity measurement you can use the internal
voice note microphone, or an external measurement micro-
phone, plugged into the XLR input. The polarity result for left
and right speaker cabinets should match for a good stereo
sound image.

• Feed the speaker cabinet with the polarity test signal of the
Minirator.
• Adjust the test level (at Minirator or amplifier) until the test
signal is clearly heard.
• Enable the polarity test signal at the left speaker cabinet;
mute the right speaker cabinet.
• To activate the internal microphone, select Signal Source
with the rotary wheel and choose Voice Note Mic with
enter . The sample result shows the polarity as:
• Measure the polarity of the left speaker cabinet and save the • Sub-woofer: Low energy, no sub installed
screenshot in the memory menu . • Woofer: Positive
• Enable the polarity test signal at the right speaker cabinet; • Mid-range: Negative
mute the left speaker cabinet. • Tweeter: Positive (with small levels)
• Measure the polarity of the right speaker cabinet.
• Compare the polarity test result of both speaker cabinets. The major part of the signal energy is measured
in the mid-range frequency bands. Therefore,
 The polarity measurement is completed. the overall displayed polarity is NEGATIVE.

89
 Delay Time

Delay Time 1 Delay Signal Source

Select the signal source for the delay measurement:
The delay time measurement function is suitable for accurate
configuration of delay line setups, by optimizing the direction- CD Player Using the NTi Audio Test CD; this set-
ality of the signal source. The XL2 measures the delay time ting implies the synchronization time bar
between the reference signal and the acoustic signal from the is set to 100 seconds = 1 min. 40 sec.;
speaker. The acoustic delay settings are displayed, allowing you after 100 seconds the XL2 has to be syn-
to easily set the measured delay time into the delay device in chronized to the delay test signal again.
the rack. The NTi Audio delay time test signal is provided either
by the Minirator MR-PRO, MR2 or the NTi Audio Test CD / USB Minirator The Minirator MR-PRO and MR2 provides
Flash Drive included with the XL2. a more reliable test signal source than a
CD player. Therefore, the XL2 offers an ex-
tended time range without synchronization.
Only after 300 seconds (5 minutes) does
the XL2 have to be synchronized to the de-
1 lay test signal again.

2 Store Button
7
2 Press the store button to record the actual delay 7 of the
3 6 reference speaker.

3 Reference Delay Time

4
Individually-stored delay time of reference speaker.
5

90
 Delay Time

4 Calculated Distance Delay Test utilizes VoiceNote Microphone

Distance from measurement position to speaker in meters The XL2 uses the internal VoiceNote micro-
or feet, based on the defined temperature in °C or °F phone to measure the acoustic delay. Do not
connect any measurement microphone to the
5 Synchronization Time Bar XL2 for the delay time measurement.
The automated synchronization allows delay time mea-
surements without any connected electrical reference
signal for 100 seconds using the NTi Audio Test CD / USB
Flash Drive or 300 seconds using the Minirator, MR2 or Rear Speaker
MR-PRO. It displays the time remaining until the next re- The rear speaker on the XL2 is disabled during
quired synchronization. delay measurements, thereby avoiding mea-
surement failures. The headphone output is ac-
6 Calculated Delay Time: Store - Actual tive.
Calculated difference between delay time of speaker A and
speaker B as shown on the next page. The automated dif-
ference calculation simplifies the verification of delay line
arrangements, such as those used in larger halls or audi-
toriums.

7 Actual Delay
Actual measured delay time referring to the electrical refer-
ence signal.

91
 Delay Time

Delay Measurement - Getting Started Test Preparations

• Prepare the delay test signal; use either the
The delay time measurement is conducted between the syn- • NTi Audio Test CD or USB Flash Drive
chronized electrical input signal and the acoustic signal mea- • NTi Audio Minirator for analog systems
sured by the built-in voice note microphone. In this example, • NTi Audio Digirator for digital or Dolby/DTS systems
the delay between speakers A and B in the illustrated audito- • Start the delay test signal.
rium is measured. • Connect the generated delay test signal with an audio cable
to the RCA or XLR input of the XL2, e.g. take the reference
speaker A speaker signal from an auxiliary channel of a mixing console.
front left front right • Select XLR or RCA input in the upper XL2 menu
lecturer • Set the actual environment temperature, to ensure that the
distance is displayed correctly later.

speaker B speaker
sub left sub right

measurement
position

92
 Delay Time

• Wait until the XL2 synchronizes to the incoming delay test Measure Reference Speaker A
signal, then the synchronization time bar fills up. • Start the delay test signal at speaker A, mute speaker B.
• Position yourself with the XL2 at the measurement position
next to speaker B sub left as indicated above. This is the
worst-case position in the auditorium with regard to acoustic
delay in the sound field. The XL2 uses the VoiceNote micro-
phone for the delay test; do not connect any measurement
microphone.

• Disconnect the audio cable, with the synchronizing signal,

from the XL2, allowing you to move around freely for the
delay measurement. When selecting Minirator as the delay
signal source, the XL2 has to be synchronized to the signal
source again after 5 minutes. When selecting CD Player as
the delay signal source, the XL2 has to be synchronized to  The XL2 measures the delay time of speaker A in reference
the signal source every 100 seconds. to the electrical input signal in milliseconds.

93
 Delay Time

Store Reference Measure Sub Speaker B

• Select the displayed 0.0 ms below Act. Delay with the rotary • Start the delay test signal at speaker B. Mute speaker A.
wheel and press enter . • Position yourself with the XL2 at the shown measurement
position. The XL2 uses the VoiceNote microphone for the de-
 The reference result of speaker A is stored for the differ- lay test; do not connect any measurement microphone.
ence calculation of delay A - B.

• Stop the delay test signal at speaker A.

 The XL2 measures the delay time of speaker B in reference

to the electrical input signal in milliseconds.

94
 Delay Time

Automated Difference Calculation Result Interpretation

• The delay time difference between speaker A and B is • The resulting time in milliseconds shows
automatically calculated and shown below the Act. Delay the time difference of the sound signal from
result. speaker A and B arriving at the measurement
position. Speaker B has to be delayed by the
displayed difference result.
 The delay time is measured. • To optimize directionality, add a further 5 ms
to the calculated difference. The main signal
from speaker A then arrives at the measure-
ment position first. The acoustic signal from
sub speaker B arrives 5 ms later. This im-
Delay Test utilizes VoiceNote Microphone proves the subjective directionality percep-
The XL2 uses the internal VoiceNote micro- tion of the listeners.
phone to measure the acoustic delay. Do not
connect any measurement microphone to the Distance in meter/feet
XL2 for the delay time measurement. The distance results in meter/feet are displayed
below for easy verification of the test results
Measurement Position accuracy. The readings are based on 330 m/s
Do not position the XL2 too close to reflecting sound speed at 0°C / 32°F.
surfaces, such as walls or floors. The reflections
are likely to prevent accurate measurements.

95
 1/12 Octave + Tolerance

1/12 Octave + Tolerance (optional) Applications

• PA-rental: Verifying the frequency response of returned
The Spectral Limits Option extends the XL2 function range speakers and microphones against reference records ensur-
with an RTA analyzer with spectral resolutions from 1/1 octave ing they are back in stock in good working condition.
down to 1/12th octave. Trace capturing, relative curve display • Industrial quality testing: Passed/Failed test in the production
and comprehensive tolerance handling are supported in the line or during service of any audible quality criteria, such as
FFT Analysis and the high-resolution 1/12 Oct + Tol spectral with motors, machines, vacuum cleaners, ...
analysis. • Cinema: Comparing frequency responses against an ideal
response curve according the X-Curve requirements.
Features
• High-resolution RTA function “1/12 Oct + Tol” with select- Tolerance Handling
able 1/1, 1/3, 1/6 and 1/12 octave spectral resolution The XL2 Analyzer compares spectral measurements against a
• Capturing of multiple readings into the internal memory tolerance band and visualizes exceptions in every frequency
• Comparing measurement results against captures with rela- band. The passed/failed condition is further visualized by the
tive or absolute curve display limit button and forwarded to the I/O interface of the instru-
• Comprehensive tolerance handling with tolerance masks ment in order to drive an external alarm device such the acces-
based on captures for passed/failed measurements sory SPL Stack Light.
• Export and import of tolerance and capture files
• Frequency band listening at rear speaker Tolerance curves can either be imported from txt-files or direct-
ly derived from captured measurements. The XL2 calculates
tolerance bands based on
• Single captured results
• Manually generated txt-files on the PC
• Mean average of multiple captures
• Min/Max curves of multiple captures

96
 1/12 Octave + Tolerance

1 Result Symbols / Capture & Start Tolerance Mode

This field offers two functions:
• Symbols for measurement results 2
14 13

Upper parameter displayed as line.

12 Lower parameter displayed as bargraph.

1
11
2

• Capture & Start Tolerance Mode

The displayed spectral readings may be captured in C1
3
- C8 for
10 • Comparing measurement results against captures
4
with relative or absolute curve display.
• Creating tolerance masks based on captures for
passed / failed measurements.
9
8

Capture EQ Captures the upper parameter

5 6 7

Capture Live Captures the lower parameter

Manage Allows to rename captures, clear record-

captures ed captures, save captures to the SD
Card for export or load captures from the
SD Card for import to the XL2.

97
 1/12 Octave + Tolerance

Start tolerance Starts the tolerance mode for passed/ 5 Input Range
mode failed measurements comparing the The XL2 Analyzer provides three input ranges to accom-
actual measurement results against a modate the wide range of input signals. The individual rang-
tolerance band. es are based on the microphone sensitivity setting in the
calibration menu of the XL2. For example at a sensitivity
2 Measurement Result S=20mV/Pa the input ranges are
Actual level result of the indicated frequency band. The cur- • Lower range: 10 - 110 dBSPL
sor readout displays the center frequency and the level of • Middle range: 30 - 130 dBSPL
the band indicated by the arrow. • Upper range: 50 - 150 dBSPL

Upper parameter displayed as line. Select the lowest possible input range according to the
maximum level expected during the measurement; e.g., if
Lower parameter displayed as bargraph. the sound pressure will be always below 110 dBSPL, then
select the lowest input range 10 - 110 dBSPL.
3 Y-Scale setting
• Select the Y-Axis with the rotary wheel and confirm 6 Time Weighting
with enter . Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 second
• Select the zoom factor between 20, 10, 5, 2.5 dB/div as well FAST (125 ms) and SLOW (1 second). Applications:
and confirm with enter .
• Scroll up and down with the rotary wheel to select the Short Time High-resolution in time with minimum
Y-axis range. Weighting averaging
• Confirm with enter .
Long Time Low resolution in time with longer aver-
4 Spectral Measurement Result Weighting aging
Spectral results in 1/1, 1/3, 1/6 or 1/12 octave band resolu-
tion. Adjust the resolution at 12 .

98
 1/12 Octave + Tolerance

7 Run Indication 9 Preset Measurement Time

The run indication shows the measurement status running, Adjustment of preset measurement time for single timer
paused or stopped. Various measurement settings are setting.
locked during ongoing measurements, such as changing
the input ranging or the preset measurement time. 10 Broadband Results
For passed/failed measurements with the Spectral Limits User-selectable display of broadband results:
option the run indication may display A for a preset auto-
mated level trigger. Broadband A A-weighted level

8 Actual Measurement Time Broadband C C-weighted level

Counts actual measurement time in hrs:min:sec. Supports
setting of time modes: continuous and single. Broadband Z without any frequency weighting

Timer Mode Continuous - none

(applicable for standard measurements)
All values are recorded and monitored continu- Sum of Sum of displayed frequency bands (only
ously after starting a measurement with start . bands available when #HideUnusedBands is
The actual measurement time is shown. set to True within the tolerance file)

Timer Mode Single

Automatically stops the measurement after the
pre-set measurement time.
• Set the required measurement time.
• Start the measurement .

99
 1/12 Octave + Tolerance

11 Readout Frequency 12 Setting of Test Result Resolution

You may select any frequency to read out individual levels. Set the spectral result display to 1/1, 1/3, 1/6 or 1/12 octave
The selected frequency is indicated by the cursor arrow. band resolution as follows:
• Turn the rotary wheel to select the parameter 12 .
Choose between the following settings: • Press enter to open the selection window.
• Turn the rotary wheel to select 1/1 OCT, 1/3 OCT,
The cursor automatically follows the highest level, 1/6 OCT or 1/12 OCT
e.g. tracing live performance feedback frequencies • Press enter to confirm.
• Select the frequency with the rotary wheel .
• Press enter . 13 Phantom Power Supply
• You may read out any individual frequency.
• Return to auto frequency with enter . 48V The XL2 provides 48 V Phantom power sup-
ply to the microphone or sensor.
 The cursor returns to the frequency with high-
est level bar. ASD An NTi Audio measurement microphone with
automated sensor detection ASD is connect-
The cursor readout may be set manually to any ed. The XL2 reads the electronic data sheet of
frequency band or wideband level. The readout re- the microphone and switches the 48 V Phan-
mains at the selected frequency. tom power automatically on.
• Select the frequency with the rotary wheel .
• Press enter . 48V Phantom power is switched off.
• Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measure-

ment results of the selected frequency band.

100
 1/12 Octave + Tolerance

14 Measurement Unit Band Listening

Select the measurement unit as follows: The selected frequency band of the input signal
is audible on the rear speaker or at the head-
dB Sound level in dBSPL phone output.
This measurement unit is permanently selected
while an NTi Audio measurement microphone • Press and hold the speaker button down.
with electronic data sheet is connected. The pop-up window Volume is displayed.
• Keep the speaker button pressed and
dBu Input level in dBu press enter at the same time.

dBV Input level in dBV  The band listening is activated.

V Input level in Volt

101
 1/12 Octave + Tolerance

1/12 Octave - Getting Started Configuration

The XL2 displays two different sound pressure levels at the
Test Preparations same time. You configure to display either the levels Live,
The XL2 reads the electronic data sheet of any connected ASD Max, Min, EQ, EQ1“, EQ4“ or captured results.
microphones provided by NTi Audio and switches the 48 V
Phantom power on automatically as follows: • Select the upper result parameter with the rotary wheel .
• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48 V Phantom power indication in the upper menu bar

changes to ASD. The XL2 is ready for acoustic measure-
ments.

• Position the XL2 at the measurement location using a micro-

phone stand or tripod.
• Select the 1/12 Oct + Tol function in the measurement
menu.

The displayed wideband and spectral levels are

measured and stored simultaneously.

• Confirm with enter .

102
 1/12 Octave + Tolerance

Select Upper/Lower Reading

 The pop-up window Select reading appears.  The pop-up window Select reading mode appears.

• Select the time-averaged sound level EQ. All available selec-

tions are Z-weighted (= no weighting).

• Select EQ for normal absolute display of measurements.

• Follow the same instruction and select the lower spectral
reading Live.

• Confirm with enter .

Press start to measure and display the
sound levels results indicated with ----.

103
 1/12 Octave + Tolerance

Select Input Range Start Measurement

Select the lowest possible input range according to the maxi- • The XL2 measures the selected sound pressure lev-
mum level expected during the measurement. els Live and EQ. All available sound levels are
• Select the input range RNGE and press enter . Z-weighted (= no weighting).
• Turn the rotary wheel to set the applicable input range and • Press start .
confirm with enter .
 The run indication switches to running . The actual sound
level Live and the averaged level EQ are displayed. The pa-
rameter RUN flashes in the memory menu.

104
 1/12 Octave + Tolerance

Stop Measurement and Data Saving Audio Recording

• Press stop . The XL2 Analyzer may record a linear audio file (48 kHz, 24 Bit)
of the measurement period together with the spectral data. Just
 The XL2 stores the measurement data automatically. load a txt-file named “12audio.txt” in the root directory of the
XL2. This requires the installed option Extend Acoustic Pack.

Capture References and Create Tolerances

The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.

Features:
• Capturing of multiple readings into the internal memory
• Comparing measurement results against captures with rela-
tive or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for passed /
failed measurements
• Export and import of tolerance and capture files
• True peak level in 1/1 and 1/3 octave resolution
• Press enter to confirm. The measurement data is stored • High-resolution Zoom-FFT up to 0.4 Hz steps in the frequen-
on the SD Card in ASCII format. cy range 5 Hz - 20 kHz

 The measurement is completed. Read the detailed description in the separate chapter
Spectral Limits Option (Capture + Tolerances).

105
 1/12 Octave + Tolerance

1/12 Octave - Fast Frequency Response Measurement in 1/3 Octave Resolution

• Select the test signal Fastpnk1 on the Minirator MR-PRO.
Measurement • Connect the MR-PRO to the input of the device under test.
• Take the XL2 and select the function 1/12Oct.
The XL2 provides fast and accurate frequency response mea- • Select the one-third octave band frequency resolution.
surement within one second using pink noise. For this pur- • Select the measurement parameter EQ, the mode “Single”
pose, the Minirator MR-PRO generates the test signal “Fast and set the measurement duration to one second.
Pink Noise” tailored to this application. • For higher frequency resolutions use the test signal Fast-
pnk4 and a measurement duration of four seconds.
Test Signal • Start the measurement .
The test signal “Fast Pink Noise” is not “random”; it contains
an absolutely flat spectrum within the cycle time. The frequen-
cy resolution of the test signal is limited to 1 / cycle time; there-
fore you can choose between two different test signals:

Minirator MR-PRO XL2 Frequency XL2

Test Signal Resolution Measurement
Duration

File -> Signals -> 1/1 Octave 1 second

Fastpnk1 1/3 Octave

File -> Signals -> 1/6 Octave 4 seconds

Fastpnk4 1/12 Octave
 You have successfully completed the measurement.

106
 1/12 Octave + Tolerance

Optimize the Frequency Response Test Signal „Fast Pink Noise“ Advantage
The fast frequency response measurement with the test sig- Frequency response measurements often use
nal “Fast Pink Noise” saves time in optimizing the frequency the standard Pink Noise in combination with
response of audio devices or speakers. During your settings a 1/n octave analysis. Because of the random-
on the equalizer, you will receive a precise result on the XL2 ness, longer averaging times are necessary to
screen within one second. get accurate results. Too short averaging times
result in “noise” in the result, as shown here:

• Select the test signal Fastpnk1 on the Minirator MR-PRO.

• Connect the MR-PRO to the input of the device under test.
• Take the XL2 and select the function 1/12Oct.
• Select the measurement parameter EQ1”, the mode “Sin-
gle” and set the measurement duration to one second.
• Adjust the settings on the equalizer.

 The XL2 displays the actual frequency response within a

second.

In comparison, the test signal “Fast Pink Noise”

enables a precise measurement result within
one or four seconds.

107
 Noise Curves

Noise Curves (optional) now used frequently for describing noise from mechanical ven-
tilation systems in buildings. To make a rating, the measured
The Spectral Limits Option extends the XL2 with the Noise noise spectrum is superimposed on a family of NR contours;
Curves measurement function. A noise curve may be used to the NR of the spectrum corresponds to the value of the first
characterize room noise or other environments. Various stan- NR contour that is entirely above the spectrum.
dardized international noise curves are the most widely used
means for evaluating background sound in buildings, and other
facilities such as transit facilities, as well as in other indoor/ Noise Criteria NC
outdoor spaces. Residual noise in buildings may be generated (in accordance with ANSI S12.2-2019 and -1995)
from both environmental sources (e.g. outside traffic) and sys-
temic sources (e.g. heating, ventilating, and air-conditioning The NC rating of a spectrum is designated as the value of the
(HVAC) systems; or other machinery in use). It is also frequently lowest NC curve above the measured octave-band spectrum.
necessary to measure residual noise curves prior to expected The designating number for any NC curve is, approximately,
changes in advance of construction or prior to other expected its Speech Interference Level (SIL): the average of the levels
environmental noise changes. in the 500, 1000, 2000 and 4000 Hz octave bands. SIL is a
simple metric, which measures the effects of noise on speech
intelligibility. The XL2 Analyzer includes the tangency method
Noise Rating NR adaptation in accordance with the standard.
(in accordance with ISO/R 1996-1971)

Noise rating (NR) is a graphical method for assigning a single Room Noise Criteria RNC
number rating to a noise spectrum. It can be used to specify (in accordance with ANSI S12.2-2019)
the maximum acceptable level in each octave band of a fre-
quency spectrum, or to assess the acceptability of a noise The RNC method is used to determine noise ratings when the
spectrum for a particular application. The method was originally noise from HVAC systems at low frequencies is high, and which
proposed for use in assessing environmental noise, but it is is also suspected of containing sizeable fluctuations or surging.

108
 Noise Curves

It essentially represents a rumble criterion. The RNC curves Room Criteria RC

also provide a procedure that reduces the result essentially (in accordance with ANSI S12.2-1995)
back to the NC curves when systems are well designed and
acoustically well-behaved. Following the RNC specification, the The RC criterion curves are a system for use in the design
XL2 measures the octave-band sound pressure level every 100 of heating, ventilating, and air-conditioning (HVAC) systems in
ms, followed by processing to determine the applicable room office buildings, dwelling units, etc., where the desired mid-
noise criterion (RNC) curve. The minimum measurement time frequency levels are in the range of 25 to 50 dB. Each RC crite-
is 20 seconds. rion curve bears a rating number equal to the level at 1000 Hz.

Spectrum classification
Preferred Noise Criteria PNC • Neutral spectrum (N): The levels at 500 Hz and below do not
(in accordance with ASA 1971) exceed the RC curve corresponding to a sound level spec-
trum by more than 5 dB; and the spectrum levels in Band
PNC curves represent a more stringent method based on an 1000 Hz and higher do not exceed the corresponding RC
extension of the basic Noise Criteria system. They have been curve by more than 3 dB.
used in the past to judge the acceptability of ventilation and • Rumble (R): Excessive noise in low-frequency band
other background broadband noise. PNC curves are less often The level in one or more of the octave bands at and below
used than Noise Criteria curves because they are more strin- 500 Hz exceeds the RC curve corresponding to a spectrum
gent at lower frequencies than the Noise Criteria curves, but by more than 5 dB.
also because the latest (2019) version of Noise Criteria curves • Hiss (H): Excessive noise in high-frequency bands
also includes an extended frequency range somewhat mitigat- The level in one or more of the octave bands at and above
ing the original reasons for PNC. 1000 Hz exceeds the RC curve corresponding to a spectrum
by more than 3 dB.
• Vibration and rattle (RV): The level in one or more of the oc-
tave bands from 16 Hz through 63 Hz exceeds the criterion
for moderately noticeable rattle.

109
 Noise Curves

Noise Curves Result Page RNC Information Page

1 12
2 11

3 13

5
14
6
10
9

7 8

The standards list the noise criteria in 5 dB steps. The XL2 The RNC information page is available when viewing Noise Cri-
measures the noise criteria in detailed 1 dB steps, which are teria and Room Noise Criteria results, in accordance with ANSI
calculated by linear interpolation between the standardized S12.2-2019. It reports any large fluctuations or surging at low
5 dB levels. frequencies, e.g. caused by fans.

110
 Noise Curves

1 Noise Curve 3 Y-Scale setting

Selection of the noise curve type and measurement re- • Auto-Scroll
sult. • Zoom:
- Select the Y-Axis with the rotary wheel and confirm
Noise Curve Types with enter .
• Noise Rating NR - Select the zoom factor between 10, 5, 2.5 dB/div and
• Noise Criteria NC (2019) and (1995) confirm with enter .
• Room Noise Criteria RNC
• Room Criteria RC (1995) 4 Noise Measurement Result
• Preferred Noise Criteria PNC (1971) Real-time spectrum in 1/1 octave band resolution.

Measurement Result 5 Noise Floor

The noise rating of a spectrum is designated as the value of The grey area shows the noise floor of the connected NTi
the highest curve “touched” by the measured octave-band Audio measurement microphone (provided by the electron-
spectrum. The octave band in which this “touching” occurs ic data sheet) in combination with the XL2 Analyzer.
is noted along with the curve designation.
6 X-Scale
2 Measurement Result X-Scale from 16 Hz to 8 kHz.
Actual level result of the indicated frequency band. The cur-
sor readout displays the center frequency and the level of
the band pointed to by the arrow. With the cursor in auto-
matic mode, the arrow points to the frequency band with
the highest noise rating as shown in 1 .

111
 Noise Curves

7 Live View 9 Actual Measurement Time

Select the LiveView with the rotary wheel to get an Counts actual measurement time in hrs:min:sec. Supports
overview of the current noise level. Alternatively press the time modes: continuous and single.
limit button .
Timer Mode Continuous
The XL2 measures the noise curve after pressing the start (applicable for standard measurements)
button . This will provide the noise rating measurement All values are recorded and monitored continu-
in accordance with all standards. ously after starting a measurement with start .
The actual measurement time is shown.
8 Run Indication
The run indication shows the measurement status running, Timer Mode Single
paused or stopped. Various measurement settings are Automatically stops the measurement after the
locked during ongoing measurements, such as the preset pre-set measurement time.
measurement time. • Set the required measurement time.
• Start the measurement .

 The actual measurement time counts back to

zero and the measurement ends.

10 Preset Measurement Time

Adjustment of preset measurement time for the timer
mode single.

112
 Noise Curves

11 Readout Frequency 12 SIL Measurement Result

You may select any frequency to read out individual levels. The speech interference level (SIL) result is shown for
The selected frequency is indicated by the cursor arrow. noise curve types NC-2019 and NC-1995 1 . It is calcu-
lated by averaging the octave-band sound pressure levels
Choose between the following settings: at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. If the measured
spectrum in any octave band does not exceed any of the
The cursor follows automatically the frequency octave bands of that NC(SIL) curve, the spectrum is des-
band with the highest noise rating. ignated NC(SIL). If one or more octave-band levels exceed
• Select the frequency with the rotary wheel . the NC(SIL) curve, then the NC curve number may differ to
• Press enter . the SIL value, as the NC rating for that spectrum must be
• You may read out any individual frequency. determined using the tangency method.
• Return to auto frequency with enter .
13 Large Fluctuations
 The cursor returns to the frequency with high- This reports any large fluctuations at low frequencies
est noise rating. for the Room Noise Criteria RNC in accordance with
ANSI S12.2-2019. If one or more displayed measurement
The cursor readout may be set manually to any results exceed the limits, then large fluctuations exist.
frequency band or wide band level. The readout re- Concluding the LEQ levels in the octave frequency bands
mains at the selected frequency. below 300 Hz are automatically “penalized” at the RNC
• Select the frequency with the rotary wheel . measurement.
• Press enter .
• Select the frequency of interest. 14 Correction Values
• Confirm with enter . The noise curve type RNC uses these correction values
based on the measured fluctuation results to determine
 The cursor readout 2 displays the measure- the RNC curve result.
ment results of the selected frequency band.

113
 Noise Curves

Recommendations
Type of Room - NC and Level RC curve Type of Room - NC and Level RC curve
Space Type RNC LAeq Space Type RNC LAeq
Curve Curve
Concert and recital - 15-18 - Family rooms and living 39-48 30-40 30-35 (N)
halls rooms

Small auditoriums 35-39 25-30 - Hotels/Motels

(≤500 seats)
Individual rooms or 39-44 30-35 25-35 (N)
Large auditoriums 30-35 20-25 - suites
(>500 seats)
Meeting/banquet 35-44 25-35 25-35 (N)
TV and broadcast stu- 16-35 15-25 - rooms
dios
Service support areas 48-57 40-50 35-45 (N)
Live performance the- 25-30 20-25 -
Office buildings
aters
Offices executive 35-44 25-35 25-35 (N)
Premier movie theaters 25-30 20-25 -
Offices small 44-48 35-40 25-35 (N)
Normal theater 30 25 -
Offices large 39-44 30-35 -
Private residences
Conference rooms 35-39 25-30 25-35 (N)
Bedrooms 35-39 25-30 25-30(N)
large
Apartments 39-48 30-40 30-35 (N)
Conference rooms 39-44 30-35 25-35 (N)
small

114
 Noise Curves

Noise Curves - Getting Started Configuration

• Select the noise curve type with the rotary wheel .
Test Preparations
The XL2 reads the electronic data sheet of any connected ASD
microphones provided by NTi Audio and switches the 48 V
Phantom power automatically on as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2 .

 The 48V Phantom power indication in the upper menu bar

changes to ASD. The XL2 is ready for acoustic measure-
ments.

• Select the Noise Curves function in the measurement

menu.

The microphone should be moved slowly to po-

sitions around the entire space at locations that • Confirm with enter .
are near the average normal standing or seated
height of human ears. The recommended mea-
surement period is more than 20 seconds long. The XL2 measures all noise curve types at the
same time, thus you can change the selection
also after the measurement.

115
 Noise Curves

Start Measurement Stop Measurement and Data Saving

• Press start . • Press stop .

 The run indication switches to running . The actual noise  The XL2 stores the measurement data automatically.
level LZeq of the selected octave band is displayed. The
parameter RUN flashes in the memory menu. The Y-axis
adjusts automatically according the measurement result.

• Press enter to confirm. The measurement data is stored

on the SD Card in ASCII format.

 The measurement is completed.

116
Noise Curves

117
 STIPA

Speech Intelligibility STIPA (optional) Signal Source

Choose the applicable STIPA test signal source:
The STIPA analyzer option allows reliable measurement
of the speech transmission index (STI) within 15 seconds. NTi Audio The NTi Audio TalkBox simulates a person talking
Besides the single value STI or CIS (= common intelligibil- TalkBox at a precise acoustic level, enabling the measure-
ity scale) test result, a detailed view of the modulation indi- ment of the complete signal chain including the
ces and individual band level results is provided. The STI- microphone.
PA analyzer meets the standard IEC 60268-16, edition 5 • Place the NTi Audio TalkBox in front of the mi-
released in 2020. The XL2 also supports noise corrections, au- crophone at the typical position of the talking
tomated averaging of measurements and the older standard persons head.
editions 2, 3 and 4. • Select Track 1 for the STIPA test signal.
• Select Output Mode to Speaker; you should
The intelligibility of speech depends on: hear the STIPA test signal.
• Signal-to-noise ratio
• Psychoacoustic masking effects Minirator The Minirator MR-PRO is used for electrical signal
• Sound pressure level MR-PRO injection into public address systems that com-
• Ambient noise level monly use alarm messages from a hard drive
• Reverberation time (systems without a microphone).
• Reflections
• Frequency response Other Audio Register the XL2 and download the STIPA test
• Distortion Player signal at https://my.nti-audio.com/support/xl2.
The maximum tolerable deviation in test signal
The speech intelligibility measurement function STIPA is an op- playback sample frequency is 0.1%.
tion for the XL2 Audio and Acoustic Analyzer. Ask your local
representative for purchasing details. The standard STIPA signal is based on random noise limited to
the bands contained in a male speech spectrum.

118
 STIPA

STIPA Numeric Result Page STIPA Table Result Page

10

1 9

8
2
7

5
6

11 12 13 14

Use only the original NTi Audio test signal for

speech intelligibility measurements with the
XL2. Other signals may not seamlessly loop,
thus causing wrong measurement results!

119
 STIPA

STIPA Averaging STIPA Ambient Noise Correction

18 24

23
15
19
22

21
16 17 20

120
 STIPA

1 Run Indication 6 Qualification Scale

This icon displays the run status of the measurement. The STI value is shown as a letter representing the qualifi-
cation scale below. Listed are also examples of typical ap-
2 Measurement Result plication environments.
• Single value speech transmission index result.
• Repeatability of measurement result: Band STI Range Examples of typical uses
Since a dedicated noise test signal is used, the result A+ > 0.76 recording studios
may deviate by a of maximum 0.03 STI (=Max-Min) at the
A 0.72 - 0.76 theatres, speech auditoria,
same measurement position.
parliaments, courts
3 Sound Level LAeq B 0.68 - 0.72 theatres, speech auditoria,
Shows the time-averaged sound level of the 15 seconds parliaments, courts
measurement cycle time. C 0.64 - 0.68 teleconference, theatres
D 0.60 - 0.64 class rooms, concert halls
4 Sound Level LAS E 0.56 - 0.60 concert halls, modern churches
Actual sound pressure level.
F 0.52 - 0.56 PA in shopping malls,
public offices, cathedrals
5 Analog Test Result Bargraph
Bargraph display and interpretation of the speech intelligi- G 0.48 - 0.52 PA in shopping malls,
bility measurement result public offices
• Exlnt 0.75 - 1.00 STI H 0.44 - 0.48 PA in difficult acoustic
• Good 0.60 - 0.75 STI environments
• Fair 0.45 - 0.60 STI I 0.40 - 0.44 PA in very difficult spaces
• Poor 0.30 - 0.45 STI J 0.36 - 0.40 not suitable for PA systems
• Bad 0.00 - 0.30 STI
U < 0.36 not suitable for PA systems

121
 STIPA

7 Measurement Unit 9 Progress Bar

The speech intelligibility result is displayed in STI (Speech Measurement status indication; a single speech intelligibil-
Transmission Index) or CIS (Common Intelligibility Scale), ity measurement takes 15 seconds. The actual measure-
whereby CIS is calculated as CIS = 1 + log STI. ment time and measurement status are indicated here.

8 Edition of Standard IEC60268-16 10 Page Selector

ed5.0 actual edition released in 2020 with continuous Select between these pages:
level dependent auditory masking function
Speech intelligibility measurement result
ed4.0 old edition released in 2011 with continuous
level dependent auditory masking function Table result page with modulation ratio and
sound levels for each octave band
ed3.0 old edition released in 2003 with stepped level
dependent auditory masking function On-site averaging of results.
ed2.0 old edition released in 1998 with fixed masking
function Ambient Noise Correction

The page button toggles between the 123 - Tab - Avr

screens. These pages show the speech intelligibility mea-
surement results. The page Cor offers setting the noise
spectra prior the STI measurement.

11 Octave Bands
Frequencies 125 Hz - 8 kHz in 1/1 octave band resolution.

12 Sound Pressure Level Leq

Individual time-averaged octave band level Leq.

122
 STIPA

13 STIPA Modulation Ratio mr1, mr2 14 Error Detection

For good speech intelligibility it is mandatory that the in- The built in error detection helps identifying faulty measure-
tegrity of the transmitted voice signal modulations are pre- ments caused by the amount of impulsive ambient noise.
served. Therefore, STIPA is based on measuring the MTF Such noise influences the accuracy of any speech intelligi-
(Modulation Transfer Function). This function quantifies the bility measurement. The error detection checks the follow-
degree to which the voice modulations are preserved in ing:
individual octave bands. The STIPA method determines the • Invalid modulation indices in individual octave bands (mr1
MTF by analyzing the seven frequency bands. Each band is or mr2 > 1.3)
modulated with two frequencies, resulting in the modula- • Changes in ambient noise or any impulsive noise dur-
tion ratio mr1 and mr2. All indexes together combined with ing the measurement (by comparing the first half of the
psycho-acoustic models provide the single-value speech measurement period with the second half)
intelligibility result.
15 Cycle Reading
The standard IEC 60268-16 recommends measuring the
Band mr1 mr2 speech intelligibility two or three times at each measure-
125 Hz 1.60 Hz 8.00 Hz ment position. This reduces potential measurement errors.
The individual cycle readings are listed here.
250 Hz 1.00 Hz 5.00 Hz
500 Hz 0.63 Hz 3.15 Hz
1 kHz 2.00 Hz 10.00 Hz 16 STI-Average
2 kHz 1.25 Hz 6.30 Hz Calculated average of the recorded cycle results.
4 kHz 0.80 Hz 4.00 Hz
17 Difference
8 kHz 2.50 Hz 12.50 Hz
Difference (Max – Min) of the of the recorded cycle re-
sults.

123
 STIPA

18 Start next Cycle Measurement 22 Spectral Level of Ambient Noise

Start the next cycle measurement at the same measure- Adjustable octave band level from 125 Hz to 8 kHz. The de-
ment position here. fault spectrum is equals the replayed STIPA test signal at
LAeq = 80 dB.
19 Ambient Noise Measure / Load / Save
Measure here the actual ambient noise during an adjust- 23 Activation of manual Octave Band Level Setting
able measurement time. You may save this record and re- Select EDIT with the rotary wheel to adjust the indi-
load the data set for any later speech intelligibility measure- vidual octave band levels.
ment.
24 Activation of Ambient Noise Correction
20 Source of Data On Ambient noise correction is active
Informs about the source of the ambient noise data. The
Off Ambient noise correction is deactivated
choices are:
• Default Settings
• Edited manually
• Measured Date Time
The XL2 Analyzer has been manufactured in
This information is documented in the measurement re- compliance with all specifications as described
port. in IEC 60268-16. Due diligence has been ob-
served in validating
21 LAeq of Ambient Noise • the measuring system
This LAeq is calculated based on the octave band levels; • the accuracy of the measured STI across a
you may manually set this level in accordance with the typi- range of relevant reference conditions
cal noise level as specified for your application. The default • the accuracy of the modulation transfer func-
level is 80 dB. tion matrix.

124
 STIPA

Question Mark ? at individual Octave Bands STI Measurement - Getting Started

Individual octave bands are marked with ? in case of a
• Missing test signal level Test Preparations
• Invalid modulation indices (mr1 or mr2 > 1.3) The XL2 reads the electronic data sheet of the connected
• Changes in ambient noise or any impulsive noise during the NTi Audio measurement microphone and switches the 48 V
measurement Phantom power automatically on as follows:

Flashing Question Marks ?.?? at 2 • Connect the measurement microphone to the XL2.
The measurement result flashes in combination with the ques- • Switch on the XL2 .
tion marks ??? in case of a
• Question Mark ? at one or multiple octave bands. See the  The 48 V Phantom power indication in the upper menu bar
STIPA Table Result Page on the XL2 for details. changes to ASD. The XL2 is ready for acoustic measure-
• Changes in ambient noise or any impulsive noise during the ments.
measurement
• Position the XL2 at the measurement location using a micro-
phone stand or tripod.
• Select the STIPA measurement function in the measure-
ment menu.
In case the question marks ?.?? are flashing, • Prepare the environment for the measurement. For example
then the measurement is faulty. Verify possible mute all sound sources to establish silence.
causes and repeat the measurement.

For details see the chapter STI Measurement No impulsive noise shall occur during the
Hints. speech intelligibility measurement as well no
speaking or other noise sources should be al-
lowed near the measurement microphone.

125
 STIPA

Start STIPA Test Signal Start Measurement

Select the STIPA signal source according your application re- • Press start .
quirements.
 The progress bar switches to RUNNING. The test result
• Switch on the STIPA test signal at the signal source. tendency is shown on the bargraph, marked with Bad,
• Set the acoustic sound pressure level of the PA system to Poor, Fair, Good and Exlnt.
simulate the typical announcement level; e.g. LAS = 85 dB.

126
 STIPA

Stop Measurement and Data Saving Averaging of STI Results

After the period of 15 seconds the speech intelligibility mea-
surement finishes automatically. The progress bar indications The standard IEC 60268-16 recommends averaging two or
switches to FINISHED and the final test result is displayed. The three subsequent results taken at the same measurement lo-
measurement result is stored automatically. cation.

• Switch off the STIPA test signal. The German Standard VDE 0833-4 requires performing mini-
mum three subsequent measurements for one measurement
position in case of STI < 0.63.

The XL2 Analyzer offers automated averaging of two up to

eight speech intelligibility results based on these standard re-
quirements.

• Press enter to confirm. The measurement data is stored

on the SD Card in ASCII format.

 The measurement is completed.

127
 STIPA

Start Averaging Add Cycles

• Select the averaging page Avr. • Press enter to confirm Add Cycle.

• Turn the rotary wheel to select the parameter START • Repeat the measurement at the same position as required.
NEW and press enter .
 The XL2 performs further measurements and adds them to
 The first measurement starts automatically. It is labeled the list.
Cyc 1.

128
 STIPA

Finish Display of STIPA Numeric Result Page

• Choose Finish to end the averaging. The symbol indicates that the averaged STI value is dis-
played.

 The speech intelligibility average and the deviation are dis-

played for documentation.

129
 STIPA

Ambient Noise Correction Enable Ambient Noise Correction

• Select the correction page Cor.
Measuring the speech intelligibility index under realistic envi- • Turn the rotary wheel to select the parameter Ambient
ronmental conditions is often not feasible; e.g., playing the test Noise Correction and press enter .
signal in a railway station at emergency levels during peak hours
will irritate passengers. Additionally, at rush-hour the charac-  The correction enables and the XL2 displays this screen:
teristics of ambient noise might be highly impulsive, while a
pre-requisite for accurate speech intelligibility measurements
is a negligible impulsivity in the ambient noise. Under such cir-
cumstances the speech intelligibility measurement should be
shifted to a more suitable time of the day; e.g. night time.

Measurement Sequence
• First measure the ambient noise
• Secondly measure the speech intelligibility

This sequence simplifies the measurement

as follows: The XL2 immediately displays the
speech intelligibility result with ambient noise
correction. This result provides a guideline if
repeated measurements at the same location
with averaging is required. For details see the You may adjust the ambient noise band levels
chapter STIPA Measurement Hints. and the LAeq.

130
 STIPA

Commissioning New PA-Systems Measure Ambient Noise

New announcement systems are commissioned e.g. at public • Position the microphone at the STIPA measurement point.
areas prior the grand opening. Thus, the actual ambient noise • Select Measure (without any test signal presence).
caused by the public is not available yet during the speech in-
telligibility measurement. Here you may simulate the real-life  The XL2 measures the ambient noise and displays the LEQ
condition with ambient noise data enabled by one of the fol- octave band result.
lowing modes:

• Utilize a reference noise file, which might be applicable for

the actual project
- Measure the ambient noise at another similar project and
store this as reference noise file.
- Back on the actual project select the parameter Load with
the rotary wheel and press enter .
- Select the reference noise file, which shall be utilized as
ambient noise correction for your speech intelligibility
measurements.

• Edit actual noise data

- Select the parameter Edit or the LAeq level with the ro-
tary wheel and press enter .
- Turn the rotary wheel to adjust the noise level.
- Press enter to continue the setting.

Skip the next step “Measure Ambient Noise” and go to “STI You may edit the noise data.
Measurement”.

131
 STIPA

STI Measurement Data Post-Processing

• Select the STIPA result page 123. In the case when no ambient noise correction has been car-
• Perform the speech intelligibility measurement. ried out on-site with the XL2 Analyzer, you may post-process
your measurement data on the PC. The NTi Audio STI Report-
ing Tool combines the speech intelligibility measurement taken
with quiet conditions and the actual ambient noise caused by
the public, e.g. during day-time. This emulates the speech intel-
ligibility expected during real-life conditions.

STI Reporting Tool

The STI Reporting Tool creates measurement reports accord-
ing to the standards

• AS 1670.4
• CEN/TS 54-32:2015
• DIN EN 50849:2017
• IEC 60268-16
• ISO 7240-19:2007
• VDE V 0833-4-32:2016
• VDE 0828-1:2017-11

 The XL2 displays the corrected speech intelligibility result Import the data directly from your XL2 including the ambient
in large font. The actual measured result is listed below in noise measurements. The corresponding speech intelligibility
smaller font. STI or CIS values are shown.

132
 STIPA

The STI Reporting Tool is free to download on the XL2 Support Utilize the ambient noise correction for such instances.
website https://my.nti-audio.com for all registered users. (En-
able all macros when opening the document.) • At locations with varying conditions (e.g., some public areas
with few people and other areas with crowds) the worst-
System Requirements: case speech intelligibility should be measured. Consult the
• PC running Windows OS local regulations (e.g. the NFPA code in the U.S.) for direc-
• Excel 2010 - 2016 tives concerning measurement locations and number of re-
quired measurements under which circumstances.

STI Measurement Hints German Standard VDE 0833-4 Requirements

Ambient Noise STI > 0.63 One single measurement is sufficient.

• The ambient noise has to be sufficiently static during the
measurement. A signal-noise ratio of 15 dB or higher is rec- STI < 0.63 Perform three subsequent measurements at this
ommended to achieve best speech intelligibility. Impulsive measurement position.
ambient noise during the measurement, such as speech, • If the maximum result deviation of these three
causes severe measurement errors. The STIPA result is usu- measurements is > 0.03 then a further three
ally too high. measurements shall be performed.
• If the maximum result deviation of these mea-
• Fluctuating noise is detected by measuring the direct STI in surements is > 0.05 then the cause of this in-
the absence of the test signal. Carry out these measurements stability shall be evaluated and removed.
at least at a representative set of locations. If the STI is too • The arithmetic average of the performed three
high (e.g. STI > 0,3), the measurement results are likely to or six measurements has to be reported.
be erroneous. In this case the speech intelligibility measure-
ment should be carried out without the presence of noise.

133
 STIPA

Utilize the STIPA Reporting Tool for the documentation of your Measurement
measurements according the standard. • Select measurement positions as stipulated by local regula-
tions. As a guideline, typically position the microphone at 1
An STI > 0.63 implies that the speech intelligibility is higher - 1.2 meters above ground in sitting areas or 1.5 - 1.8 meters
than 0.5 with a confidence level of 95%. in standing areas. Also, directly in front of the speakers or
very close to a wall are examples of positions that are not
typical.
CD-Player
• Only high-quality CD-Players should be used to reproduce • The person taking the measurements should be out of the
the STIPA test signal as only limited time-shifts (+/- 20 ppm) acoustic field, so as not to affect the measurement results.
ensure reliable test results. Pitch control and shock protec- For this purpose, the measurement microphone can be
tion should be disabled. We recommend that only profes- mounted on a microphone stand and connected with the
sional CD-Players be used. You can verify the time shift of the ASD Cable to the XL2.
CD-Player using a 1 kHz test signal:
- Insert the NTi Audio Test CD into the CD-Player and start • Low speech intelligibility readings can be caused by
track 1, which is the 1 kHz test signal. - Excessive sound reverberation, echoes or reflections
- Connect the XL2 directly to the audio output of the CD- - Poor speaker directivity or speaker coverage
Player and measure the signal frequency in RMS/THD+N - Speaker level setting incorrect; e.g. low signal-to-noise ra-
mode. The displayed frequency should be in the range tio.
from 0.99998 kHz to 1.00002 kHz

• STIPA test signals from other test system manufacturers

may sound similar but are not compatible. Only the original
NTi Audio STIPA test signal should be used in combination
with the XL2.

134
 Audio Analyzer

6. Audio Analyzer RMS / THD+N

The XL2 offers a comprehensive audio analyzer. Broadband The XL2 Audio and Acoustic Analyzer measures the parame-
or wideband measurements are offered by the measurement ters Level RMS, THD+N and frequency simultaneously.
functions RMS/THD+N and Oscilloscope.

The following measurement functions offer detailed analysis of

the audio spectrum in Volt, dBu and dBV: 5
• SLMeter/RTA 1
• FFT
• 1/12 Oct+Tol (optional)
2

Just change the measurement unit according your require-

ments. See the individual chapters for more details. 3

• If an NTi Audio measurement microphone 4

with electronic data sheet is connected,
the XL2 will automatically activate the unit
dBSPL (dB) for sound level measurements.
• A decreased THD+N performance will occur
with unbalanced input signals when using
switching-type power supplies (approx. 3 dB).
Remove such a mains adapter for critical ap-
plications.

135
 Audio Analyzer

1 Filter 2 Level RMS

Measures the absolute level of the input signal. The unit’s
Z-Weighting Frequency Z-weighting with flat frequen- dBu, dBV, Volt V, dBSPL, Watt W and dBm are selectable.
cy response from 20 Hz to 22 kHz. De- The Watt and dBm measurement results are calculated
fault measurement setting. based on a user-defined Load. The unit dBSPL is not avail-
able for the type approved XL2-TA firmware.
A-Weighting Frequency A-weighting according
IEC 61672 for low noise levels. 3 THD+N
Measures the total harmonic distortion and noise of the
C-Weighting Frequency C-weighting according input signal. The distortion measurement, expressed in dB,
IEC 61672 for high noise levels. linear or in %, is conducted within the bandwidth 10 Hz - 20
kHz. This value is calculated as follows:
HP-100Hz Highpass 100 Hz, -200 dB/dec., THD+N = (Distortion+Noise) / (Signal + Distortion+Noise)
maximally flat magnitude filter,
e.g. -60 dB @ 50 Hz 4 Frequency in Hz
The XL2 automatically extracts and measures the frequen-
HP-400Hz Highpass 400 Hz, -120 dB/dec., maxi- cy of the fundamental signal. The XL2 frequency counter
mally flat magnitude filter, attenuates technology even reads the frequency correctly for heavily
50/60Hz components of test signal distorted signals.

HP-19k Highpass 19 kHz; e.g., to measure a

20 kHz pilot tone level of a public address
system without disturbing the public.

22.4-22.4k Bandpass filter 22.4 Hz - 22.4 kHz

(IEC 468-4)

136
 Audio Analyzer

5 Balance Indicator PreNotch Listening

Indication of the audio signal balance between pin 2 and 3 The input signal is audible at the rear speaker or
on the XLR input for input signals > -34 dBu. headphone output.
The input signal is balanced.
• Press and hold down the speaker button .
The signal is unbalanced. The level at pin 2 is
higher than at pin 3.  The pop-up window volume is dis-
The signal is unbalanced. The level at pin 3 is played.
higher than at pin 2.

137
 Audio Analyzer

PostNotch Listening Oscilloscope

The main frequency component is filtered out
by a notch filter, leaving only the remaining sig- The scope function visualizes the waveform of the electrical in-
nal audible. put signal. It automatically triggers to the fundamental frequen-
cy and selects the scaling of the X-axis (time) and Y-axis (level)
• Press the speaker button to display the vol- accordingly. The fundamental, or most dominant, frequency of
ume window. the input signals is displayed above the scope screen.
• Additionally, press enter

 The post notch listening with auto-gain

function is activated. The maximum gain
setting is 0 dB.

e.g. using a 100 Hz sine test signal connected

to the XL2 input, with the 100 Hz main fre-
quency filtered by the notch filter, the complete
frequency spectrum is available at the speaker
or headphone output. This feature allows you to
listen to the actual distortion signal. You there-
fore hear a noise from the speaker even without
any connected inputs signal! The scope scaling is fixed.

138
 Vibration Meter

7. Vibration Meter VibMeter / Spectrum

The Vibration Option turns the XL2 Audio and Acoustic Analyzer The vibration meter offers different pages:
into a professional vibration meter with broadband measure-
ments and spectral analysis in 1/3 or octave resolution. The Page Selection using the Page Button
XL2 Vibration Meter determines vibration acceleration, velocity • Press page to toggle between the 123 VibMeter page
and deflection with standard-compliant weighting filters in the and the CPB page.
frequency range from 0.8 Hz to 2.5 kHz. Detailed recording
of measurement data and audio files allow for comprehensive Page Selection using the Rotary Wheel
evaluation and reporting. In addition, the XL2 Vibration Meter • Select the page 123 VibMeter with the rotary wheel .
comes standard with an FFT analysis and an oscilloscope func- • Confirm with enter .
tion. Selectable FFT frequency ranges from 1 Hz to 1.69 kHz
allow a detailed examination of the measured vibrations.

The Spectral Limits Option adds functions to the Vibration Me-

ter including a zoom FFT up to 20 kHz and a 1/12 octave band
analysis from 0.73 Hz to 1.36 kHz. Also, it adds the ability to
record reference spectra and set tolerances for pass / fail qual-
ity control measurements. The Remote Measurement Option
allows the real-time acquisition of measurement data directly
into a computer application via the USB interface. A document-
ed command set is available.

Page Selection

139
 Vibration Meter

123 Values: Vibration Meter Logging: Setup of Data Logging

Displays the selected broadband vibration level results. You can The XL2 features a powerful vibration level meter data logger,
change the font size of the result. Depending on the font size which allows you to record all required vibration level values
chosen, the XL2 shows 2 up to 4 results simultaneously. The during the measurement. In the logging page you set which
display of the actual or maximum level can be selected with vibration levels shall be logged over time. For details refer to
the applicable frequency weighting. The peak levels PK or P-P the chapter Logging. Choose between:
are real peak levels.
ALL Logs all vibration levels.

Spectrum: Constant Percentage Bandwidth CPB Selected Logs up to 10 different individually-defined vibra-
Displays the 1/3 or 1/1 octave spectrum of the selected RMS, tion levels.
peak or peak-peak vibration level. Additionally, the wide band
result B is shown graphically by a bar.
Limit LED: Limit Setting
Here you set the function of the limit LED , thereby highlight-
Reporting: Report Setting ing any vibration level that exceeds the pre-set limits in orange
Here you set which vibration levels shall be stored in a .txt file or red color. Further, external peripherals are controlled by the
after the completed measurement. Choose between: optional Serial I/O Interface based on the vibration level, such
as displaying vibration levels on a large external red-orange-
ALL Stores all vibration levels. green lamp. For details refer to the chapter Limits.

Selected Stores up to 10 different individually-defined vi-

bration levels.

For details refer to the chapter Reporting.

140
 Vibration Meter

Overview
Numeric Result Page Constant Percentage Bandwidth Analyzer Page
The numeric result page 123 Values displays the selected The real-time analyzer page Spectrum measures and dis-
broadband vibration level results. You can change the font plays the 1/3 or 1/1 octave spectrum in the selected frequency
size of the result. Depending on the font size chosen, the XL2 range including the wideband result.
shows 2 up to 4 results simultaneously. The display of the ac-
tual or maximum level can be selected with the applicable fre-
quency weighting.

11 10

1 4

5
6

2
7
9
3

141
 Vibration Meter

1 Vibration Level Result 1 3 Filter

All vibration levels are measured and logged simultaneous- Select one of the following frequency filters:
ly. You select which vibration levels should be displayed.
FLAT no filter applied
Change Parameter
• Turn the rotary wheel to select the parameter Lxx. 1-80Hz Filter 1 - 80 Hz with decay rate of 12 dB /
• Press enter to open the selection menu and choose octave in accordance with DIN 45669-1
the wideband vibration level to be displayed.
• Turn the rotary wheel to select the required test result 1-315Hz Filter 1 - 315 Hz with decay rate of 12 dB /
parameters and confirm with enter . octave in accordance with DIN 45669-1

Change Font Size 10-1000Hz Filter 10 - 1000 Hz with decay rate of 18 dB /

• Turn the rotary wheel to select the actual test result. octave in accordance with ISO 2954
• Press enter 1x, 2x or 3x to set the font size to small,
medium or large. 4 Result Symbols / Capture
This field offers two functions:
The XL2 shows 2 vibration levels on the display if a large
font is chosen, otherwise it shows 4 vibration levels. • Symbols for measurement results 11

2 Vibration Level Result 2 Upper parameter displayed as line.

Follow the setting instructions for vibration level result 1.
Lower parameter displayed as bargraph.

142
 Vibration Meter

• Capture 6 Y-Scale setting

One of the displayed frequency band readings may be • Select the Y-Axis with the rotary wheel and confirm
captured. Any measurement data can then be compared with enter .
with this captured reference live on the XL2 Analyzer. • Select the zoom factor between 20, 10, 5, 2.5 dB/div and
confirm with enter .
• Select the parameter to be captured. • Scroll up and down with the rotary wheel to select the
• Confirm with enter , to capture the reading. Y-axis range.
• Select the upper parameter 15 and choose Capt. • Confirm with enter .
• Confirm with enter .
7 Measurement Result
 The lower reading can be compared with the previously- Real-time analyzer results in 1/1 octave or 1/3 octave band
captured reference data. resolution.

5 Level Type 8 X-Scale setting

Select in the System Settings: Third-octave band resolution
• metric or imperial units
• RMS, peak or peak-peak level 2.5 Hz - 2.5 kHz frequency band levels including wide
band result

Upper parameter displayed as line. 0.8 Hz - 1.0 kHz frequency band levels including wide
band result
Lower parameter displayed as bargraph.
0.8 Hz - 2.5 kHz frequency band levels

143
 Vibration Meter

Octave band resolution 11 Measurement Result

Actual level result of the indicated frequency band. The cur-
4 Hz - 2.0 kHz frequency band levels including wide sor readout displays the center frequency and the level of
band result the band pointed to by the arrow.

1 Hz - 0.5 kHz frequency band levels including wide Select the measurement unit as follows:
band result
Acceleration a • m/s2
1 Hz - 2.0 kHz frequency band levels • g
• in/s2
• Select the X-Axis with the rotary wheel and confirm • dB
with enter .
• Toggle with the rotary wheel between the ranges. Velocity v • m/s
• Confirm with enter . • in/s
• dB
9 Broadband Results
Displays broadband level B. Displacement d • m
• in
10 Filter • dB
Select the preset frequency filter here, which is already
used on the broadband page.

144
 Vibration Meter

Wav-File Recording Sample name of wav-file:

MyTest_V_Meter_000_Audio_FS_2.52e2_mps2(PK)_00.wav
The XL2 records a wav-file of the measured input signal and
stores it on the SD Card. The available formats are:
• Compressed (default, using ADPCM compression). A new 1 2 3 4 5

wav-file is started automatically after 12 hours of recording

(typical maximum wav-file size = 512 MByte)
• Compressed+AGC, compressed with automated gain con- 1 MyTest
trol. The gain control increases the level of low-level signals, File name defined by user.
so that the wav-file is well-leveled during playback on the
PC. 2 SLM
• 24Bit_48kHz, linear wav-file logging in 24 bit, 48kHz resolu- Measurement function.
tion with the optional Extended Acoustic Pack. A new wav-
file is started automatically after 1 hour of recording (typical 3 000
maximum wav-file size = 512 MByte) Automatically incrementing file number.

4 Audio_FS_2.52e2_mps2(PK)
Audio file with full-scale peak level based on acceleration
Broadcast Wave Format BWF in unit m/s2. In case of a Compressed + AGC recording,
The XL2 stores scaling factor, serial number, the file name reads “AGC”; this file contains corrected level
date, time and time zone within the wav-file (ac- information only.
cording to EBU TECH 3285). This information is
available through professional audio/video tools 5 00
typically used in broadcast. The number increments for each successive wav-file during
a longer recording.

145
 Vibration Meter

FFT Analysis + Tolerance

The XL2 Vibration Meter includes a fast real-time FFT.
9 8

The following features are available upon installing the Spectral

Limits Option in the XL2 Analyzer:
• High-resolution Zoom-FFT up to 0.4 Hz steps in the frequen- 7
1
cy range 1 Hz - 20 kHz 6
• Capture and tolerance function provided with Spectral Limits 2

Option; thus the main menu function reads FFT + Tol.

3

146
 Vibration Meter

1 Result Symbols / Capture & Start Tolerance Mode Manage Allows to rename captures, clear re-
This field offers two functions: captures corded captures, save captures to the
• Symbols for measurement results 2 SD Card for export from the XL2 or
load captures from the SD Card for im-
Upper result displayed as line. port to the XL2.

Lower result displayed as bargraph. Start tolerance Starts the tolerance mode for passed/
mode failed measurements comparing the
actual measurement results against a
• Capture & Start Tolerance Mode tolerance band.
The displayed readings may be captured as reference
reading C1 to C8 for 2 Measurement Result
• Comparing measurement results against captured Actual level result of the indicated frequency band. The cur-
traces with relative or absolute curve display. sor readout displays the center frequency and the level of
• Creating tolerance masks based on captured refer- the band indicated by the arrow.
ence curves for passed / failed measurements.
Upper parameter displayed as line.

Capture EQ Captures the upper parameter Lower parameter displayed as bargraph.

Capture Live Captures the lower parameter Select in the System Settings:
• metric or imperial units
• RMS, peak or peak-peak level

147
 Vibration Meter

3 Y-Scale setting 6 Readout Frequency

• Select the Y-Axis with the rotary wheel and confirm You may select any frequency to read out individual levels.
with enter . The selected frequency is indicated by the cursor arrow.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div Choose between the following settings:
and confirm with enter .
• Scroll up and down with the rotary wheel to select the The cursor follows automatically the highest level,
Y-axis range. e.g. tracing the dominant frequency of a rotating
• Confirm with enter . part.
• Select the frequency with the rotary wheel .
4 Measurement Result • Press enter .
Displays the actual and averaged measurement results. • You may readout any individual frequency.
• Return to auto frequency with enter .
5 Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 sec-  The cursor returns to the frequency with high-
onds as well FAST (125 ms) and SLOW (1 second). est level bar.

Applications: The cursor readout may be set manually to any

Short Time High-resolution in time with minimum frequency. The readout remains at the selected fre-
Weighting averaging quency.
• Select the frequency with the rotary wheel .
Long Time Low resolution in time with longer aver- • Press enter .
Weighting aging • Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measure-

ment results of the selected frequency band.

148
 Vibration Meter

7 Zoom Mode 8 Measurement Unit

(optional, applicable with the Spectral Limits Option) Select the measurement unit as follows:

• Select the readout frequency 10 and press enter . Acceleration a • m/s2

• The zoom mode is displayed above the flashing arrow. • g
• Select the zoom-in frequency with the rotary wheel . • in/s2
• Press limit and zoom the linear frequency scale in or • dBa
out with the rotary wheel .
• Release limit and scroll the linear frequency scale left Velocity v • m/s
or right with the rotary wheel . • in/s
• dBv

Displacement d • m
• in
• dBd

The Spectral Limits Option extends the function with cap-

tures and tolerances. All tolerances are specified as accel-
eration.

149
 Vibration Meter

9 Page Selector X-Scale and Parameter Setting Oscilloscope

1k7 Shows FFT result of the frequency band range. The scope function visualizes the waveform of the electrical in-
23 Hz - 1.687 kHz in a resolution of put signal. It automatically triggers to the fundamental frequen-
11.72 Hz with 143 bins shown on the display. cy and selects the scaling of the X-axis (time) and Y-axis (level)
accordingly. The fundamental, or most dominant, frequency of
400 Shows FFT result of the frequency band range. the input signals is displayed above the scope screen.
5 Hz - 421.02 Hz in a resolution of 2.92 Hz with
143 bins shown on the display.

100 Shows FFT result of the frequency band range.

1 Hz - 105.00 Hz in a resolution of 0.73 Hz with
143 bins shown on the display.

Usr User Range

(applicable with optional Extended Acoustic Pack
or Spectral Limits Option)
1 Hz - 20 kHz in zoom mode with a minimum reso-
lution of 0.366 Hz and 143 bins displayed.

Set Selection for FFT Windowing:

• Hann: Default setting
• Dolph-Chebyshev: for analyzing small signals
(e.g. harmonics) close to a dominant signal.
The scope scaling is fixed.
The page button switches these display modes.

150
 Vibration Meter

1/12 Octave + Tolerance (optional)

8
The Spectral Limits Option extends the function range of the
XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high- 7
1
resolution 1/12 Oct + Tol spectral analysis. 6
2
Features:
• Capturing of multiple readings into the internal memory 3

• Comparing measurement results against captures with rela-

tive or absolute curve display 4
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for passed /
failed measurements

151
 Vibration Meter

1 Result Symbols / Capture & Start Tolerance Mode Manage Allows to rename captures, clear re-
This field offers two functions: captures corded captures, save captures to the
• Symbols for measurement results 2 SD Card for export from the XL2 or
load captures from the SD Card for im-
Upper result displayed as line. port to the XL2.

Lower result displayed as bargraph. Start tolerance Starts the tolerance mode for passed/
mode failed measurements comparing the
actual measurement results against a
• Capture & Start Tolerance Mode tolerance band.
The displayed readings may be captured as reference
reading C1 to C8 for 2 Measurement Result
• Comparing measurement results against captured Actual level result of the indicated frequency band. The cur-
traces with relative or absolute curve display. sor readout displays the center frequency and the level of
• Creating tolerance masks based on captured refer- the band indicated by the arrow.
ence curves for passed / failed measurements.
Upper parameter displayed as line.

Capture EQ Captures the upper parameter Lower parameter displayed as bargraph.

Capture Live Captures the lower parameter Select in the System Settings:
• metric or imperial units
• RMS, peak or peak-peak level

152
 Vibration Meter

3 Y-Scale setting 6 Readout Frequency

• Select the Y-Axis with the rotary wheel and confirm You may select any frequency to read out individual levels.
with enter . The selected frequency is indicated by the cursor arrow.
• Select the zoom factor between 20, 10, 5, 2.5 dB/div Choose between the following settings:
and confirm with enter .
• Scroll up and down with the rotary wheel to select the The cursor follows automatically the highest level,
Y-axis range. e.g. tracing the dominant frequency of a rotating
• Confirm with enter . part.
• Select the frequency with the rotary wheel .
4 Measurement Result • Press enter .
Displays the actual and averaged measurement results. • You may readout any individual frequency.
• Return to auto frequency with enter .
5 Time Weighting
Offers selectable time weighting of 0.1, 0.2, 0.5, 1.0 sec-  The cursor returns to the frequency with high-
onds as well FAST (125 ms) and SLOW (1 second). est level bar.

Applications: The cursor readout may be set manually to any

Short Time High-resolution in time with minimum frequency. The readout remains at the selected fre-
Weighting averaging quency.
• Select the frequency with the rotary wheel .
Long Time Low resolution in time with longer aver- • Press enter .
Weighting aging • Select the frequency of interest.
• Confirm with enter .

 The cursor readout 2 displays the measure-

ment results of the selected frequency band.

153
 Vibration Meter

7 Setting of Test Result Resolution 8 Measurement Unit

Set the spectral result display to 1/1, 1/3, 1/6 or 1/12 octave Select the measurement unit as follows:
band resolution as follows:
• Turn the rotary wheel to select the parameter 12 . Acceleration a • m/s2
• Press enter to open the selection window. • g
• Turn the rotary wheel to select 1/1 OCT, 1/3 OCT, • in/s2
1/6 OCT or 1/12 OCT • dBa
• Press enter to confirm.
Velocity v • m/s
• in/s
• dBv

Displacement d • m
• in
• dBd

The Spectral Limits Option extends the function with cap-

tures and tolerances. All tolerances are specified as accel-
eration.

154
Vibration Meter

155
 Calibration

8. Calibration
The XL2 Audio and Acoustic Analyzer meets or exceeds the Environmental Conditions
specifications listed in the chapter Technical Data. The sound level meter and calibrator should be exposed to the
same environmental conditions prior any calibration for the fol-
Instrument Calibration lowing recommended periods:
In order to maintain the high accuracy, annual calibration of • 10 minutes after a temperature change of 10°C.
the XL2 Analyzer and the measurement microphone is recom- • 15 seconds after the static air pressure has changed by
mended. The calibration service verifies the complete product 5 kPa.
specifications, differences to the last calibration and measures • 10 minutes after a humidity change of 30% without conden-
the frequency response of the measurement microphone. To sation.
enquire about calibration service, follow the RMA guide lines
at www.nti-audio.com. The described calibration method and correction data apply for
the following environmental conditions:
• Temperature: -10 °C to +50 °C
Microphone Sensitivity • Static air pressure: 65 kPa to 108 kPa
NTi Audio’s ASD measurement microphones and the micro- • Humidity: 25 % to 90 % r.H.
phone pre-amplifier MA220 include an electronic data sheet. without dew from -10 °C to +39 °C
The Automated Sensor Detection (ASD) of the XL2 recognizes
the sensitivity and calibration data of the connected micro-
phone. The electronic data sheet, including the microphone Ambient Noise
sensitivity, is displayed in the menu Calibrte. Please make sure that, during the calibration with 114 dB, the
ambient noise level is lower than 89 dB.

156
 Calibration

Calibration Menu with connected Calibration Menu without any connected Sensor
Measurement Microphone

7
6
5
4
2 9

157
 Calibration

Calibration Menu with connected 1 Phantom Power Supply

ICP Adapter ASD and Accelerometer
48V The XL2 provides 48 V Phantom power supply
to the connection microphone or sensor.

ASD An NTi Audio measurement microphone with

automated sensor detection ASD is connect-
ed. The XL2 reads the electronic data sheet of
the microphone and switches the 48 V Phan-
10 tom power automatically on

48V Phantom power is switched off.

2 Electronic Data Sheet of Measurement Microphone

Read out data from the connected microphone.

3 Factory Sensitivity
Factory sensitivity of the connected sensor.

4 Level Type

LZF Default setting.

LHP100F Suppressing any low frequency noise, for

example wind during outdoor calibrations.

158
 Calibration

5 Start Field Calibration 8 WP30 1/2” for vertical noise incidents using the
Select RUN and press enter to start the sensitivity setting Aircraft WP30 Weather Protection; no spec-
using an external calibrator. tral correction applies

6 Level of External Calibrator WP61 1/4” for horizontal noise incidents using
The reference calibration level is 114 dB. The XL2 Supports Community the WP61 Weather Protection
a level setting between 0 dB and 200 dB.
WP61 1/4” for vertical noise incidents using the
7 Sensitivity Aircraft WP61 Weather Protection; no spec-
Applicable microphone sensitivity in the range from tral correction applies
1 µV/Pa to 9.99 V/Pa. The sensor detection of the XL2 reads
the sensitivity automatically from the electronic datasheet M22xx DF 1/2” Diffuse-field correction for measure-
of the connected NTi Audio microphone or preamplifier. ment microphones M2230, M2340,
M2215, M2211
8 Spectral Correction
Select one of the spectral corrections as applicable. This M42xx DF 1/4” Diffuse-field correction for measure-
selection can be activated in the System Settings Set page ment microphone M4261
at position 11 . The correction data is listed in chapter Tech-
nical Data. 9 Selection Sound Level Meter / Vibration Meter

Sound Sound Level Meter

Off no spectral correction.
Vibration Vibration Meter
WP30 1/2” for horizontal noise incidents using
Community the WP30 Weather Protection

159
 Calibration

10 Unit Selection Accelerometer Sensitivity • Press enter and adjust the sensitivity with the rotary
The accelerometer sensitivity is provided in the range of wheel .
• 1 µV/(m/s2) - 10.0 V/(m/s2) or • Confirm with enter .
• 10 µV/g - 100 V/g

Field Sensitivity
The XL2 writes the field-sensitivity setting onto
Field Calibration - With External Sound Calibrator the electronic data sheet of the connected NTi
Field-sensitivity setting for measurement microphones with an Audio measurement microphone, microphone
external calibrator. preamplifier or ASD Adapter. All subsequent
• Turn the rotary wheel to select the parameter User Cali- measurements automatically utilize this field-
bration 6 and press enter . sensitivity.
• Set the calibration level according to the calibrator used. In case the measured sensitivity deviates ±1.5
• Generate the specific reference signal with the calibrator dB for a class 1 microphone and ±3 dB for a
onto the microphone. class 2 microphone to the nominal microphone
• Turn the rotary wheel to select the parameter RUN 5 sensitivity, then the XL2 displays the following
and press enter . message: Measured sensitivity to far (xxdB)
• The pop-up window Calibration: Calibration running ... ap- from factory settings. Check calibration level
pears and changes to Calibration: Successfully finished! and microphone!
for a successfully completed calibration. In doubts kindly contact NTi Audio with the de-
Field Calibration - Manual Sensitivity Setting tails.
In case no external calibration device is available, set the sensi-
tivity of non-NTi Audio sensors manually according to the prod-
uct specifications as follows:
• Select Sensitivity 7 with the rotary wheel .

160
 Calibration

Free-field Correction Example - Field Calibration

The following free-field correction shall be applied using the • Configuration
NTi Audio Class 1 Sound Calibrator - XL2 + M2230 Measurement Microphone
• M2230, M2340, M2211, M2215: -0.1 dB - NTi Audio Class 1 Sound Calibrator @ 114.0 dB

The following correction shall be applied using the NTi Audio • The level 1 at User Calibration shall be set to 113.9 dB
Class 1 Sound Calibrator with 1/4” adapter ADP 1/4-P (=114.0 - 0.1).
• M4260: +0.1 dB
• M4261: +0.2 dB

The NTi Audio microphones are free-field equalized measure-

ment microphone. Thus, they already compensate the in- 1
creased level by the presence of the microphone body in the
free-field. Pressure conditions apply during the calibration.
Therefore, the level in front of the 1/2” microphone diaphragm
differs by -0.08 dB with reference ambient conditions.

• M2230 with 50 mm Wind Screen

The correction value is +0.12 dB and the XL2 has to be set
to a calibration level of 114.0 dB (=114-0.08+0.12).
• M2230, M2340 with 90 mm Wind Screen
The correction value is +0.19 dB and the calibration level on
the XL2 has to be set to 114.1 dB (=114-0.08+0.19). • Select the parameter RUN and press enter .
• M2230, M2340 with WP30 Wind Screen 90 mm
The correction value is +0.19 dB and the calibration level on  The field calibration is completed.
the XL2 has to be set to 114.1 dB (=114-0.08+0.19).

161
 Calibration

Applying Correction Values @ M2230

The goal is to measure the sound pressure without the influence
of the microphone in the air. However, the presence of the mi-
crophone body in the free-field environment affects already the
sound pressure level at high frequencies. The measurement mi-
crophone acts at high frequencies like a reflector. The sound
pressure increases in front of the microphone capsule mem-
brane. For example, the sound pressure level is 114.0 dB in the
free field prior installing the microphone. Now the measurement
microphone is placed into the free field. The pressure in front of
the capsule is increased by 0.1 dB at 1 kHz. However, since the
sound without microphone influence shall be determined, the
free-field equalization of the M2230 compensates this effect. The
XL2 Sound Level Meter reads the accurate measured value of
114.0 dB and not 114.1 dB.

If the Class 1 Sound Calibrator is placed on the M2230 measure-

ment microphone, then the pressure conditions applies to the
microphone capsule. The pressure in the volume of the calibrator
matches the pressure on the membrane surface of the micro-
phone. Now the free-field equalization and the pressure condi-
tions for the calibration have to be taken into account. Thus, the
XL2 has to be adjusted to a calibration level of 113.9 dB when us-
ing the M2230. This applies for calibrations at reference ambient
conditions and an accurate calibrator output level at the reference
sound pressure level.

162
 Profiles

9. Profiles Profiles - Getting Started

Profiles are templates of measurement setups. You may define Activate Profile Selection at Startup
which profile is loaded at startup, so that the measurements
are carried out always with the same setup and instrument set- • Select Show profile list 1 in the System menu.
tings. • Press enter to activate Yes. This will show the profile list
at startup.
A remarkable advantage of the XL2 is the flexible user inter-
face. The measurement screens may be personalized and only
a limited subset of the comprehensive functionality enabled
to create simplified operator interfaces. Advanced users may
access all menus, settings and store their preferred measure-
ment configurations. For simplicity the XL2 Audio and Acoustic
Analyzer offers fixed operator interfaces with specific pre-de-
fined settings. The XL2 can boot up with exactly the required
1
measurement parameters according to the pre-defined instru-
ment configurations. This ensures accurate measurements are
achieved in both advanced and basic usage environments.

 The profile list is shown next time you power up the XL2.

163
 Profiles

Preset Measurement Function Store MyProfile

• Start the XL2 Analyzer in Full mode. • Select Profile in the main menu and press enter .
• Select the typically-used measurement function and adjust
the measurement parameters according to the requirements.  The profile menu opens.

For example, measuring the sound levels LAF, LAeq and

LAFmax for 10 seconds:

164
 Profiles

• Select Manage and press enter . • Select Save Profile and press enter .

 The Manage Profile menu opens.  The Save Profile menu opens.

Each stored profile includes all settings of all • Select Rename and press enter .
measurement functions and pages. Only the • Set the profile name to MyProfile. The maximum name
following details are not stored: length is 20 characters.
• Calibration settings
• System settings
• Temperature unit
• Phantom power on/off

165
 Profiles

• Select Configure available screens and press enter . Select Profile at Startup
• Switch on the XL2

 The profile selection is shown on the display.

• Select additional available pages/measurement functions for

the profile; e.g. RTA .
• Press escape to return to the Save Profile screen.
• Set Append mode available: yes in order to have the ap-
pend data feature available in the memory menu . • Select the profile MyProfile and press enter .
• You may enable manual measurement range setting within
your profile. Select Allow manual ranging: yes.  The XL2 starts up with the pre-configured settings for
• The correction values defined in KSET may be part of the sound level monitoring.
profile for selectable profiles with different corrections.
• Select Save and press enter .

166
 Profiles

Select Profile during Operation Run Measurement

• Select Profile in the main menu and press enter . The profile name is displayed when a measurement function
is highlighted. The main menu offers only the measurement
 The profile menu opens. functions enabled by the profile, plus the calibration and profile
menu.

• Press start .

• Choose Select and load the required profile.

• Wait 10 seconds until the measurement is finished.

• To return to the full mode either switch off the XL2 again
or select EXIT Profile in the main menu.

167
 Profiles

Export MyProfile to PC Import MyProfile from PC

If you have two or more XL2 Audio and Acoustic Analyzers, • Connect another XL2 to the PC and generate a folder called
you may like to transfer the same profiles to the other instru- “Profiles” on the SD Card.
ments. • Copy the profile called MyProfile into the folder “Profiles”.
• Start up the XL2, select Profile in the main menu and press
• Select Profile in the main menu and press enter . enter .
• Select Manage and press enter . • Select Manage and press enter .
• Select Export to SD-Card and press enter . • Select Import from SD-Card and press enter .

 The XL2 generates a folder on the SD Card called “Profiles”.  MyProfile is available on the other XL2 Analyzer.
All available profiles are exported into this folder.

• Connect the XL2 to the PC.

• Copy/paste the profile called MyProfile to the PC. If the profile is exported from an XL2 Analyzer
with activated options to another XL2 Analyzer
without options, then these options have to be
hidden prior to storing the profile for export:
• In the exporting XL2 system menu, select the
individual option and toggle with enter to
Hidden.
• Store the profile in the XL2 Analyzer.

168
 Profiles

The XL2 can store up to 20 individual profiles in the internal Secured Secured profiles are locked user profiles with
system memory and offers three different profile types: profiles overwrite protection indicated by the file name
ending in “xxx.prfs”. This file name cannot be
Types Description overwritten.
Sample filename: MyProfile.prfs
Factory The XL2 includes factory default profiles, which
default are marked with “#” in the beginning of the file How to generate secured profiles
profiles name. Sample filename: #DIN15905-5.prfs • Export the profiles to SD Card according to
the procedure in the chapter Profile - Getting
The factory default profiles are a free Started.
download for all registered XL2 cus- • Connect the XL2 to the PC.
tomers on the support website at • Select the user profile in the folder “Profile”.
https://my.nti-audio.com. For details see the • Manually change the ending of the user pro-
chapter My NTi Audio. file from “xxx.prfl” to “xxx.prfs”
• Disconnect the XL2 from the PC.
For detailed settings of factory default profiles • Import the profiles from the SD Card
please see the Appendix 2 in this manual. • Power off/on the XL2 Analyzer

User User profiles are profiles generated by you on  The secured profile is displayed with a lock-
profiles the XL2 Analyzer. symbol in the profile selection window on
Sample filename: MyProfile.prfl startup of the XL2.

169
 Capture + Tolerances

10. Spectral Limits Option Capture the EQ Measurement Results

• Select the Capture & Start Tolerance Mode symbol for cap-
(Capture + Tolerances) turing the measurement result.

The Spectral Limits Option extends the function range of the

XL2 with trace capturing, relative curve display and compre-
hensive tolerance handling for the FFT Analysis and the high-
resolution 1/12 Oct + Tol spectral analysis.

Features:
• Capturing of multiple readings into the internal memory
• Comparing measurement results against captures with rela-
tive or absolute curve display
• Comprehensive tolerance handling
• Creating tolerance masks based on captures for passed /
failed measurements

• Confirm with enter .

170
 Capture + Tolerances

 A pop-up window appears.  The pop-up window ... and store it to appears.

• Select Capture EQ. • Select C1.

• Confirm with enter . • Confirm with enter and set the capture name in the dis-
played letter selection box e.g. to Ref.

 The capture has been stored in the internal XL2 memory.

171
 Capture + Tolerances

Edit Capture Manually See the difference between Live Level and Capture
• Select the Capture & Start Tolerance Mode symbol. • Blank the upper parameter by setting ----.
• Confirm with enter . • Select the lower parameter with the rotary wheel .
• Select Manage captures. • Confirm with enter .
• Confirm with enter . • Select Live and confirm with enter .
• Select Save to SD card.
 The pop-up window Select reading mode appears.
 The pop-up window Save captures appears.

• Select the capture to be exported, e.g. C1.

 The pop-up window Save capture C1 to appears.

• Confirm with Save.

 The XL2 generates the file MyCapture.txt in a new folder

called Captures.

• Edit the sound level data in the capture file. All frequency
data has to remain the same.
• Load the new capture file with Manage captures back into
the internal XL2 memory.
• Select Live - for displaying the relative difference.
• Confirm with enter .
• Select Ref and confirm with enter .
• Set the Y-axis accordingly to show the zero-line.

172
 Capture + Tolerances

Manual Editing of Capture Data

Kindly observe the following rules while manually editing cap-
 The relative difference between the Live level and the cap- ture data:
tured reference is displayed. • The spectral levelAnalyzer
%1/12 Octave data is Z-weighted, thus the sum of all
Capture
bands has to equal the Z-weighted broadband level.
%‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐DO NOT EDIT THIS SECTION‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
• The A and C-weighted
#Capture time broadband levels are calculated ob-
serving22.04.2015
the corresponding
13:55 correction factors.
• Enter -999
#Levelifunit
nothing shall be deducted at certain broadband
levels ordBrfrequency bands.
#Octave resolution
1/1 Octave
%‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐EDIT ONLY LEVELS HERE!‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐
#A‐weighted broadband level
32.74
#C‐weighted broadband level
‐999
#Z‐weighted broadband level
33.17
#Columns
Frequency Level
#Spectrum
16 ‐999
31.5 ‐999
63 ‐999
125 10.5
All levels differences (relative levels) are dis- 250 20.5
played in the unit dBr. 500 25.7
1000 28.6
2000 25.5
4000 23.4
8000 24.5
16000 ‐999
173
 Capture + Tolerances

Start Tolerance Mode for Passed/Failed Measurements

• Select the Capture & Start Tolerance Mode symbol with the
rotary wheel .  A pop-up window appears.

• Confirm with enter . • Select Start tolerance mode.

• Confirm with enter .

174
 Capture + Tolerances

Passed Result

 The pop-up window Make tolerance from appears.  The tolerance mode is active for passed/failed measure-
ments.

The passed/failed condition is further visualized by the bicolor

“limit” button and forwarded to the I/O interface of the instru-
ment in order to drive an external alarm device such as the
accessory SPL Stack Light.
2 3

• Select Ref to load the earlier captured reference spectrum.

• Confirm with enter .

You may press the page button to toggle

between the date and spectral resolution data
of the capture.

175
 Capture + Tolerances

1 PASSED / FAILED Result Failed Result

The XL2 Analyzer compares spectral measurements against a
PASSED The actual measurement result is within the tolerance band and visualizes exceptions 1 in every frequen-
tolerance band. cy band.

The actual measurement result is outside of

the tolerance band. Exceptions are visual-
ized in any out-of-tolerance frequency band.

1
2 Tolerance Bandwidth
Adjusts the tolerance bandwidth based on the captured ref-
erence spectrum in dB.

3 Level Offset
Provides a level offset in dB to shift the tolerance band up
or down.

Select another Tolerance File

• Select the tolerance Ref with the rotary wheel .
• Confirm with enter .
• Select the new tolerance file from the SD Card or the internal
XL2 memory.

176
 Capture + Tolerances

Tolerance Menu Advanced Start Functions

You may start the passed/failed measurement in one of the
following ways:
1 • Press the XL2 start button .
• Activate the automated level trigger in the tolerance file.
• Activate the digital input 1 via the external I/O interface; e.g.
2
a foot switch or a PLC control.
3

Digital I/O Interface

Result Passed: Output 1
Result Failed: Output 3
Start Measurement: Input 1

Tolerance Management
Tolerance curves can either be imported from txt-files or direct-
1 Capture & Start Tolerance ly derived from captured measurements. The XL2 calculates
Opens capture and tolerance menu. tolerance bands based on
• Single captured results
2 Tolerance Type • txt-files generated manually on a PC
Select between high/low, high or low tolerance band based • Mean average of multiple captures
on the reference data set. • Min/Max curves of multiple captures

3 Frequency Range
Setting of start and stop frequency of the tolerance band.

177
 Capture + Tolerances

Create Tolerance Files Manually on PC

• Capture a spectrum on the XL2 Analyzer. • All entries in the customized tolerance file
• Enter the tolerance mode and generate a tolerance band for need to be tab-separated.
the capture. • The individual tolerance file entries may be in
• Select the Capture & Start Tolerance Mode symbol. any order; no sequential order required.
• Confirm with enter . • Tolerance file templates and standardized tol-
• Select Save tol. to SD Card to export the capture tolerance erance files are a free download for all regis-
file. This file includes the reference capture and the tolerance tered XL2 customers on the support website
data. The XL2 generates a txt-file in the folder “Tolerances”. at https://my.nti-audio.com. For details see
• Open the capture tolerance file with a text editor or MS Ex- the chapter My NTi Audio in this manual.
cel.
• Edit the tolerance data according to your requirements.
Change only the Min, Ideal and Max column values. You may
delete rows, but do not change the frequency column val-
ues. Any rows where frequency column values have been
changed will be discarded by the XL2.
• Store your individual tolerance file as a txt-file in the XL2
folder “Tolerances”.
• Start the XL2 tolerance mode and load the new tolerance file
from the SD Card.

178
 Capture + Tolerances

Band-limited Measurement Range

Alternatively to the settings on the XL2, the tolerance may also The XL2 shows selectable broadband values with A, C or Z-
be limited to a range of frequency bands or a number of indi- weighting on the right-hand side of the spectrum.
vidual frequencies on a computer.

• Open the tolerance file on the computer.

• Delete all not required frequency bands.
• Set #Hide UnusedBands to True.
• Save the file changes.
• Load the updated tolerance file in the XL2.

Alternatively select the following averaged or summed levels:

• Bands E-Sum: Sum of displayed frequency bands
• Bands E-Mean: Energy-averaged level of displayed frequen-
cy bands, e.g. the bands 80 dB and 70 dB produce 77.4 dB.
• Bands A-Mean: Arithmetically-averaged level of displayed
frequency bands, e.g. the bands 80 dB and 70 dB produce
75 dB.

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 Capture + Tolerances

#Unit
dBr #Unit dBr (relative), fixed setting

#Mode
HighLow
#Mode Describes tolerance type; the XL2 allows set-
#Columns ting of the tolerance type independently of the
Frequency Min Ideal Max tolerance file.
#ATolerances
UNDEF 80 undef 90 HighLow Utilizes upper and lower toler-
ance based on ideal reference.
#ZTolerances
UNDEF 80 undef 90
High Utilizes only upper tolerance
#BandTolerances based on ideal reference.
20 70 undef 80
1000 70 undef 80
Low Utilizes only lower tolerance
1000 73 undef 77
4000 73 undef 77 based on ideal reference.
4000 70 undef 80
20000 70 undef 80 #Columns Column headings for further tolerance data
#LevelOffset separated into columns:
0 Frequency / Min / Ideal / Max

#HideUnusedBands
#ATolerances Defines the tolerance band for the
false
A-weighted wideband level (not mandatory).
#nAllowedViolations
0
#CTolerances Defines the tolerance band for the
C-weighted wideband level (not mandatory).

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 Capture + Tolerances

#ZTolerances Defines the tolerance band for the #Hide Defines the way measurement results are
Z-weighted wideband level (not mandatory). UnusedBands shown.

#BandSum Defines the tolerance band for the True Measurement results of fre-
Tolerances sum of displayed frequency bands (not man- quency bands without any
datory). specified tolerance are not
displayed. The total level of all
#Band • Defines the tolerance band for the individual shown bands (sum of bands) is
Tolerances frequencies. available as a broadband result.
• The ideal parameter can be set as “undef”.
• The same frequency value on two succes- False The measurement result of all
sive rows defines a tolerance step, e.g.: frequency bands are shown.

Frequency Min Ideal Max #nAllowed Allows a PASSED result with a maximum
100 70 75 80 Violations number of n failed frequency bands (not man-
datory)
500 70 75 80
500 75 80 90
1000 75 80 90

#LevelOffset All levels in the tolerance file are relative levels

dBr. Thus, the level offset provides the relation
between the relative level and actual sound
pressure level. (not mandatory)
The XL2 allows setting of the level offset inde-
pendently of the tolerance file.

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 Capture + Tolerances

#FreqScale Defines the frequency scale spacing in the X- #AutoStartTrig- Sets the sound level in dBZ for an automated
Spacing axis for the tolerance data. (not mandatory) gerLevel level trigger; the passed/failed measurement
starts as soon as the set level e.g. 95 dB is
lin Tolerance data displayed with reached or exceeded. The actual input level
linear frequency spacing, e.g. can be monitored at the input range bar. (man-
used in the FFT function. (de- datory if #AutoStart is True)
fault setting)
#AutoStartSet- Defines the settling time, after the auto start
log Tolerance data displayed with tlingTime trigger level is exceeded, until the start of the
logarithmic frequency spacing measurement; the time is set in 100 millisec-
e.g. used in the 1/12 Oct + Tol ond steps e.g. setting 0.5 equals a settling
function. time of 0.5 seconds. If the input level drops
below the auto start trigger level during this
#AutoStart Enables auto start function. (not mandatory) period, no measurement is carried out. (not
mandatory)
True Auto start is active. The run indi-
cation displays A. The measure- #MeasTime Defines the measurement time in 100 millisec-
ment starts automatically after ond steps; e.g. setting 1.5 equals a measure-
the trigger level is reached. ment period of 1.5 seconds. (not mandatory)
Alternatively the measurement
may start manually by pressing #FailDeadTime Defines the delay for a failed condition in sec-
start . onds; for example, the XL2 triggers “failed” if
the measurement result is beyond the toler-
False No auto start function. (default ance limits for e.g. 60 seconds. This feature
setting) supports condition monitoring applications.
(not mandatory)

182
 System Settings

11. System Settings 2 Page Selector

Toggles with the page button between
The various system settings of the instrument can be adjusted
as follows: Turn the rotary wheel to navigate to the main Set System setting
menu 1 and select System. Confirm with enter .
Vib Vibration (applicable only upon installing the Vibra-
tion option and selecting the vibration menu)
Settings
Sch Scheduler

1 2 Opt Options

Inf System information

3
4 3 Auto power off
If no button has been pressed for the defined time period,
5
then the instrument switches off. The auto power off mode
is disabled when a measurement is running or when an
6
external mains power supply is used.
7
8
• Select Auto power off with the rotary wheel .
9 • Confirm with enter .
10 • Set the auto power off time with the rotary wheel .
11 • Confirm with enter .

183
 System Settings

4 Backlight 5 Date and Time Setting

Toggle the backlight with the power/backlight button . The XL2 includes a real-time clock. All measurements are
The backlight offers three different conditions: logged with a date and time stamp.
• On
• Dimmed Time Zone Select your time zone
• Off
DST/ Sum- Activate this for daylight saving
mer time
Auto On/Off The backlight switches off if no key is
pressed for 2 minutes. Date Date in yyyy:mm:dd

Auto The backlight dims if no key is pressed Time Time in hh:mm:ss

On/Dimmed for 2 minutes.

Manual The backlight can be toggled between Set the real-time clock as follows:
On, Dimmed and Off. • Select the Date function 5 with the rotary wheel .
• Confirm with enter .
• Navigate the cursor to the backlight function. • Set the date with the rotary wheel .
• Toggle with enter to set this parameter. • Confirm each setting with enter .
• Follow the same procedure for Time.

Dimming the backlight reduces the power  You have set the real-time clock.
consumption.

184
 System Settings

6 Show Profile List 8 Speaker

You may configure the XL2 to start up with individual preset Enables/disables the rear speaker. For example, it is recom-
application profiles. For example, sound level monitoring in mended that the rear speaker be disabled for all acoustic
accordance with DIN 15905 or V-NISSG. measurements. This prevents measuring the audio feed-
back sound loop generated through the rear speaker.
Yes The instrument starts up with default application
profiles. Further details about the application pro- 9 USB Mode
files are in the chapter Profiles. This defines how the PC recognizes the connected XL2:

No The instrument starts up in the last configuration Ask on Select either the Mass storage or COM port
without any application profiles. connect mode after connecting the XL2 to the PC.

7 Phantom Power Mass The PC recognizes the XL2 as a mass storage

You can select if the phantom power should be activated or storage device automatically, allowing you to down-
disabled when the XL2 is powered up. load XL2 measurement reports.

Off The phantom power is switched off when COM The PC recognizes the XL2 as a COM port au-
the XL2 is powered up; e.g. when it is port tomatically for application of the XL2 Projector
common to measure lines. PRO and the Remote Measurement Option.

Remember The XL2 remembers the setting prior to

the last shutdown. (= default setting)

185
 System Settings

10 Decimal Separator Vibration

Set the decimal separator to match the generated mea-
surement reports to the PC settings. This simplifies data This page is available upon switching to the vibration menu,
post-processing on the PC. which requires an installed Vibration-Option. Vibration is select-
• Navigate to the Dec. Separator function 8 with the ro- ed in the calibration menu.
tary wheel .
• Toggle between “ . ” and “ , ” with enter to set this
parameter.
1

 The decimal separator is set.

11 Calibration Menu Setting

2
Setting of the calibration menu.

Standard The default calibration menu is displayed.

Show This setting is required to activate the re-

Spec. quired weather protection or diffuse-field
Corr. correction in the calibration menu.

1 Selection Metrical-Imperial Units

Units selection

2 dB Reference
Definition of the reference parameters for dB results

186
 System Settings

Scheduler The XL2 Analyzer offers automated scheduled measurements

without any human interaction. You may schedule a measure-
ment for one or multiple days or ever.

XL2 Actions after pressing Start Schedule

• Selects the preset measurement function.
• Standby until start time
1
• Starts measurement at start time
2
3
• Stops measurement after the preset measurement duration
• Stores measurement data to SD Card (no reconfirmation re-
quired)
4
• Stops schedule or standby until next start time.
5
6

Supported measurement functions:

7
• SLMeter/RTA
• FFT + Tol
• RT60
• 1/12 Oct + Tol
• STIPA

187
 System Settings

1 Function 5 Days
Select the measurement functions for the scheduled mea- Select the week days for the recurrence
surements.
6 End
2 Start Date and Time Set the number of occurrences of the scheduled measure-
Set the date for the scheduled measurement(s): ment. Each week day is one occurrence. Select between
• Select Start with the rotary wheel . 1 to 99 occurrences or an endless schedule (= never).
• Confirm with enter .
• Set the date with the rotary wheel . 7 Start Schedule
• Confirm each setting with enter . Starts the scheduled measurement(s).

Set the time for the scheduled measurement:  The Scheduler active window is displayed.
• Select the T symbol to the right of the date.
• Confirm with enter .
• Set the time with the rotary wheel .
• Confirm each setting with enter .

3 Scheduled Duration
Set the scheduled duration of the measurement(s). The ac-
tual settings of the selected measurement function apply.

4 Recurrence

Off Schedules a single measurement.

On Schedules a measurement sequence with the

same start and end time for the selected days.
188
 System Settings

Scheduling - Getting Started Options

After starting the scheduled measurement, the XL2 waits for
the next scheduled start date and time. The instrument buttons
are disabled.

Power Supply
It is recommended that the instrument remains powered on
until the next start time, using the accessory mains power
adapter. If the XL2 is powered off and on again during this time,
then the XL2 Analyzer restarts in the Scheduler function and
continues the countdown. This applies also for any interruption
of mains power supply.

Stopping the Scheduler

Press and hold the start/stop button to stop the scheduler
prior to the start of the measurement or as an interrupt of any
ongoing scheduled measurement.
Displays the options installed on the XL2.
Operation with PC
Starting the schedule switches the USB interface automatically Every installed option may be temporarily Hidden to generate
into the COM port mode for remote measurement applications a profile for other XL2s without this option installed.
or using the XL2 Projector PRO software.
• Select the installed option.
• Toggle with enter to set this parameter.

189
 System Settings

Information

1
2

1 Serial Number
Displays the instrument’s serial number.

2 Firmware
Displays of the firmware version number (to update the
firmware to the latest version see the chapter Firmware
Update of XL2.

190
 Data Management

12. Data Management 1 Create New Project Folder

Add a new folder with an individual project name. The maxi-
The XL2 stores all acquired measurement data including real- mum length of the project name is 16 characters. A fast
time information onto the removable SD Card. Additionally, way for creating new folder names is
wav-files might be recorded and individual voice notes added • Select an existing folder name with DIR
for a complete documentation of the measurement. • Select NEW
• Rename the folder and confirm with start , thereby
• Carry out a sound level measurement. creating a new folder name.
• Select the memory menu in the upper menu bar.
• Press enter . The memory menu opens. 2 Select Project Folder
An overview of all existing project folders is shown. Select
1 2 a folder to store the results of the measurements.

3 Project Folder Name

All measurements are stored in this project folder.
3

4 4 Autosave
5
Setting of auto or manual data file naming and saving
6
7
On The results are named and stored automati-
8
cally in the selected project folder.
9
10 Off A question mark appears in the upper menu
bar at the end of the measurement. You
can choose to individually name and store
each single measurement.

191
 Data Management

Assisted A pop up menu appears after each measure- 9 Free Memory

ment. You may select to keep or delete the Displays the remaining available memory on the SD Card.
stored measurement records.
The XL2 prevents a memory overflow. SD Cards are not de-
5 Save Test signed for a 100% memory usage; the XL2 keeps at least
Stores the measurement in the selected project folder. 2% or 50 MB empty.

6 Save Screenshot The XL2 deactivates the audio recording 50 MB before this
Stores the XL2 screen in the selected project folder. limit is reached and reports this on the display.

7 Load Test In the case where only 2% or 50 MB remains, the XL2

Loads back previously-stored result data from the SD Card • deactivates the data logging and reports this on the dis-
for detailed examination on the instrument screen. play.
• disables Save Test and Autosave
8 Append Mode • saves the report at the end of the current measure-
The append mode stores one or more results into the same ment.
data file, simplifying data analysis and handling on the PC.

Application example:
When measuring the acoustic spectrum at various loca-
tions within the same venue, the append mode allows you
to store all the measurement results into one single data
file.

192
 Data Management

10 Write Cache (available with Extended Acoustic Pack) Memory Structure of SD Card
A low Write Cache level indicates that the SD Card is per-
forming well. The optional Extended Acoustic Pack with
simultaneous 100ms logging and linear wav-file recording
results in high data volumes being written to the SD Card.
1
Some non-original SD Cards may overload (OVLD), caus-
2
ing the loss of some measurement data. Verify the Write
3
Cache of your SD Card during your measurements. Use
only original SD Cards. We recommend SD Cards from the
manufacturers SanDisk and Transcend. 1 Projects
The folder Projects contains subfolders with the stored
measurement results. The default subfolder name is
“MyProject”. You can create further individual subfolders.
Original SD Cards ensure that all measurement
data and audio wav-files are stored in good or- 2 XL2.htm
der on the SD Card. Non-original SD Cards may This file opens the XL2 instrument status page, with Serial
lead to low performance or errors. Number, Firmware and Installed Options.
Order information: see chapter Accessories.
The page also provides links for online
• Firmware updates
In case the SD Card is full, you can insert the • Activation of Options
original spare SD Card into the XL2 and contin-
ue with the measurements. The XL2 generates 3 XL2_SYS
the projects and system folders automatically. The XL2 system folder contains a file with serial number,
firmware version and installed options - DO NOT EDIT THIS
FILE.

193
 Data Management

Measurement Data - Getting Started Select Parameters for Measurement Report

• Select the Rep page in the sound level meter function and
Enable Data Logging set the parameters as follows:
• Select the Log page in the sound level meter function and
set the logging parameters; e.g., as follows:

 The data logging is enabled. The sound pressure level will

be logged each second while the measurement is running.

194
 Data Management

Complete the Measurement Manual Data Saving

• Press page to return to the numeric result page. • In the case when the instrument is used with the setting
• Press start . The sound level measurement is now run- Autosave: Off, a question mark appears after the completed
ning. measurement .
• Press stop to complete the sound level measurement. • Now you may store the measurement data manually.
• Select the memory menu with the rotary wheel and
confirm with enter .
 The measurement data is stored automatically using the
factory settings. In the memory menu „Autosave: As-
sisted” is activated.

• Press enter to confirm Save Test.

 The pop-up window Save Test appears.

195
 Data Management

Select File Name Predefined Save Names

Generate a text file with user defined save
names, such as “Room1”, “Room2”, ..., and
store it as “savenames.txt” in the root directory
of the XL2. Just use names with letters or num-
bers - special characters are not supported.

• Name the first part of the file name. The maximum length of
the first part is 12 characters. The next part “_SLM_001” is
defined by the XL2 to avoid overwriting of existing measure-
ments, whereby “SLM” is the appendix for the measure-
ment function and “001” is an automatically-incrementing
number. The XL2 displays the first line of the txt-file in
the Save Test selection menu at manual data
saving.

196
 Data Management

Record Voice Notes Save Measurement Data

With the internal voice note microphone, record a Voicenote

to save with the test to remind yourself at a later stage where
and/or under which conditions the measurement was done.
• Select Record Voicenote and press enter .

• Select SAVE and confirm with enter .

 The measurement data including test configurations and all

log files are stored on the SD Card.

• Select REC and press enter .

• Record the voice note and press enter to finish. Overwrite File
Disabling Automatic Numbering allows results
 The voice note has been recorded. to be overwritten with new results.

197
 Data Management

Save Screenshot Measurement Data Logging:

• Select the memory menu with the rotary wheel and If the battery runs out while you are measur-
confirm with enter . ing with logging and/or repeated-reporting en-
abled, the XL2 creates the folder RESTORE_AF-
 The memory menu opens. TER_POWERFAIL and stores the measurement
data up until the switch-off time. The next time
• Select Save Screenshot and press enter . you switch on the XL2, the following window
• Select the file name and confirm SAVE with enter . informs you that this data exists. Click OK:

There may be invalid data at the end of the file,

 The screenshot is saved to the SD Card. which you can delete manually to create a valid
report.

198
 Data Management

View Project Folder on the PC  The PC recognizes the XL2 as a mass storage device. The
• Connect the XL2 with the USB cable to the PC. following SD Card content is shown:

 The pop-up window USB Mode appears.

• Open the folder “Projects” and the subfolder “MyProject”.

 All stored measurement data files are shown.

If the XL2 is started with USB connection to PC,

• Select Mass Storage and confirm with enter . then the COM port mode is automatically acti-
vated for remote measurement or the XL2 Pro-
jector PRO software. Therefore, if you want to
access the data in the SD Card, then first start
the XL2 and thereafter connect the USB cable
to the PC.

199
 Data Management

Overview of Measurement Data Files 3 Measurement Report File

Final report after the completed measurement. For more
details please see the chapter Sound Level Meter: Report-
1 ing.
2
3
4 Wav-File
4
The wav-file is the recorded audio file. The index
5
“FS133.0dB(PK)” in file name represents the full-scale
6
peak level of the recorded wav-file. For more details please
7
see the chapter Sound Level Meter: Wav-File Recording.

5 RTA Log File

The XL2 logs the detailed real-time analyzer spectra in pre-
defined time intervals. For more details please see chapter
1 Test System File Sound Level Meter: Logging.
System file for use by XL2 only. It contains the measure-
ment data and test configuration of the last measurement 6 Voice Note
cycle for later reload and view of measurement results in A voice annotation can be recorded for each stored mea-
the XL2. surement or screenshot. For more details please see the
chapter Data Management: Voice Notes.
2 Sound Level Log File
The XL2 logs sound levels in pre-defined log time intervals. 7 Screenshot
For more details please see the chapter Sound Level Me- Picture of the actual XL2 display.
ter: Logging.

200
 Data Management

The log data file may become very big during Transfer Measurement Data to PC
long-term measurement applications. As soon • Drag and drop the required data files to the PC.
the file size reaches 2 GB during the ongoing
measurement, the file is saved with the index 1
and a new data file created with index 2. Card Reader
Alternatively the SD Card can be inserted into
XL2 Data Explorer Software combines all these a card reader. This offers a faster data transfer
data files together seamlessly. from the SD Card to the PC.

Additional Data Files using Repeat Mode

For sound level measurements with timer mode
Repeat or Repeat Synchronized the following
additional data files are generated:
• MyTest_SLM_000_123_Report_Rep.txt
• MyTest_SLM_000_RTA_Report_Rep.txt

Common xxx_Report.txt files contain the mea-

surement data of the last measurement cycle.
The xxx_Report_Rep.txt file contains the results
of all measurement cycles in the Repeat or Re-
peat Synchronized mode.

Microsoft Excel
The generated .txt files are best viewed on the
PC using “Open with” -> Microsoft Excel.

201
 Data Management

Log File Format Report File Format

File name: e.g. MyTest_SLM_000_123_Log.txt File name: e.g. MyTest_SLM_000_123_Report.txt
XL2 Broadband Logging MyProjects\MyTest_SLM_000_123_Log.txt
XL2 Sound Level Meter Broadband Reporting MyProjects\MyTest_SLM_000_123_Report.txt
---------------------
-----------------------------------------

# Hardware Configuration
# Hardware Configuration
Device Info: XL2, SNo. A2A-02673-D1, FW2.20
Device Info: XL2, SNo. A2A-02673-D1, FW2.20
Mic Type: NTi Audio M4260, S/N: 1486, User calibrated 2011-04-05 13:56
Mic Sensitivity: 27.3 mV/Pa Mic Type: NTi Audio M4260, S/N: 1486, User calibrated 2010-11-05 13:56
Mic Sensitivity: 27.3 mV/Pa
# Measurement Setup
Timer mode: continuous # Measurement Setup
Timer set: --:--:-- Append mode: OFF
Log-Interval: 00:00:01 Timer mode: continuous
k1: 0.0 dB Timer set: --:--:--
k2: 0.0 dB k1: 0.0 dB
kset Date: k-Values not measured k2: 0.0 dB
Range: 30 - 130 dB kset Date: k-Values not measured
Range: 30 - 130 dB
# Time
Start: 2011-05-15, 17:44:06 # Broadband Results
End: 2011-05-15, 17:44:16 Start Stop
Date Time Date Time LAeq LCPKmax
# Broadband LOG Results [YYYY-MM-DD] [hh:mm:ss] [YYYY-MM-DD] [hh:mm:ss] [dB] [dB]
Date Time Timer LAeq_dt LAeq LAFmax_dt LCPKmax_dt 15.11.2010 17:44:06 15.11.2010 17:44:16 89.3 119.0
[YYYY-MM-DD] [hh:mm:ss] [hh:mm:ss] [dB] [dB] [dB] [dB]
15.11.2010 17:44:07 00:00:01 97.0 97.0 102.4 119.0
15.11.2010 17:44:08 00:00:02 85.8 94.3 91.9 105.7
15.11.2010 17:44:09 00:00:03 73.8 92.5 85.2 102.4
15.11.2010 17:44:10 00:00:04 79.0 91.4 85.3 103.9
15.11.2010 17:44:11 00:00:05 72.6 90.4 75.9 94.8
15.11.2010 17:44:12 00:00:06 67.3 89.6 71.4 87.3
15.11.2010 17:44:13 00:00:07 91.2 89.9 95.3 112.3 Data Post-Processing
15.11.2010 17:44:14 00:00:08 92.7 90.4 97.1 113.2
15.11.2010 17:44:15 00:00:09 79.3 89.9 81.6 97.9 A Microsoft Excel form generating an automated sound level
15.11.2010 17:44:16 00:00:10 78.0 89.5 82.5 98.1
15.11.2010 17:44:16 00:00:10 50.9 89.3 67.4 79.9 measurement report and chart is available as a free download
# Broadband LOG Results over whole log period for all registered XL2 customers on the support website at
15.11.2010 17:44:16 00:00:10 89.3 89.3 102.4 119
Level LAeq_dt “delta t” https://my.nti-audio.com. (Enable all macros when opening the
Level within the logging interval. e.g. If the logging document.)
interval is 1 second, then LAeq_dt is the time-
averaged level of each second.

202
 Data Management

XL2 File Validator Recall Measurements

A check sum is written to the file at the end of every measure-
ment report. The XL2 Analyzer calculates the check sum auto- The straight-forward but powerful Load Test and Save Test
matically based on the data content of the file. Using the XL2 functions serve the dual purpose of conveniently retrieving
File Validator PC-software, the contents of a data file may be standard test setups for repeat testing and also of saving
verified at any time. e.g. authorities can verify if the XL2 report stored result data for later recall and examination on screen.
file is original or the data has been manually modified.
The following measurement functions support the recall func-
The software ”XL2 File Validator” is available for download for tion:
all registered XL2 customers at https://my.nti-audio.com. • SLMeter, sound level meter
• FFT Analysis
• RT60 Reverberation time
• 1/12 Octave Band Analysis
• Noise Curves
• STIPA, speech intelligibility measurement

203
 Data Management

Load Test Select File Name

• Select the memory menu with the rotary wheel and • Select Load Test and confirm with enter .
confirm with enter .
 The pop-up window Load Test appears.
 The memory menu opens.

• Select the project folder and stored data file name with DIR.
• Select LOAD, confirm with enter .

204
 Data Management

View Measurement Data Append Measurements

 The previously stored measurement data is displayed. The append mode stores the results of several individual mea-
surements into the same data file, thus simplifying measure-
ment result analysis and data handling on the PC.

The following measurement functions support the append

mode:
• SLMeter, sound level meter
• STIPA, speech intelligibility measurement

Application example:
The sound level LAeq shall be measured at various locations in
the same venue hall using a pink noise test signal. The append
mode allows to store all individual measurement results into
one single data file.

Backup the stored measurement data from the

XL2 to the PC daily. This prevents any data loss
The run indication 1 shows the pause symbol. if data has been deleted from the SD Card by
You may continue with the measurements di- mistake.
rectly, e.g., choose the measurement function,
setup parameters and press start .

205
 Data Management

Start the Append Mode Select Filename

• Select SLMeter and preselect the sound level LAeq.
• Select the memory menu with the rotary wheel and
confirm with enter .

 The memory menu opens.

• Select Start Append Mode and confirm with enter .

• Name the first part of the file name. The maximum length of
the first part is 12 characters. The next part “_SLM_001” is
defined by the XL2 to avoid overwriting of existing measure-
ments, whereby “SLM” is the appendix for the measure-
ment function and “001” is an automatically-incrementing
number.
 The Start Append Mode window opens. • Select START and confirm with enter .

 The append mode is available.

206
 Data Management

Take Measurement Results Store Measurement Results

• Measure the sound level LAeq on the first position.
• Select the memory menu and Append Data.  The pop-up window Append Data appears.

• Select the location ID and measurement ID, thus each mea-

surement result is stored with an individual description for
later documentation.
• Select Append with the rotary wheel and confirm with
enter .

In append mode, the XL2 does not store:

• Log files
• Wav-files
• Repeated report files generated in timer
mode repeat and repeat synchronized.  The measurement data is stored on the SD Card.

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 Data Management

Append Further Measurement Results Append After Power Up

• Move to the next location in the room, carry out the mea- You can continue to add measurement results into the same
surement and follow the described append data procedure. data file at any time later.

• Store the measurements in the append mode and switch the

Exit Append Mode XL2 off and on again .
• Open the memory menu .
• Select Exit Append after adding the last measurement.  The pop-up window Continue append appears.

Auto Append
Alternatively the XL2 can append measurement
data to the same report file automatically.

• Start the Append mode and set Auto Append

is ON in the memory menu or in the pop-up
window Start Append Mode.

Skip Append Data

If you select SKIP in the Append Data window,
then no measurement data is appended to the
report file.

• Select Yes and continue adding measurement results to the

same report file in the append mode.

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 Data Management

Recall Previous Measurements for Append

Any previously stored measurement with the remark for ap-
pend can be recalled and further test records appended.

• Select Load Test and press enter .

• Select the project folder and stored data file name.
• Select LOAD confirm with enter .

 The pop-up window Load for Append appears.

• Select Continue and add further measurements to the same

report file in the append mode.

209
 XL2 Projector PRO

13. XL2 Projector PRO Software

The Projector PRO displays the XL2 screen in real-time via Additionally, the Projector PRO software offers the ability to
USB on the connected Windows or Mac computer. The soft- retrieve measurement data from the XL2 without interruption
ware toolbar enables control of the XL2 with the mouse and to the measurement process. The entire file system of the XL2
keyboard. The background color turns from green to red syn- is available while the XL2 is measuring.
chronized with the XL2 limit button color according to the
user-defined limits. The “XL View” and the “Sound Level Predictor” require that
the Projector PRO Option or the Remote Measurement Option
The “XL View” and the “Sound Level Predictor” display extend be installed on the XL2.
the XL2 Projector PRO for live sound monitoring applications.
• The “XL View” window presents sound levels in large size Projector PRO software is a free download for all registered
on the connected computer screen. Users may select to XL2 customers on the support website https://my.nti-audio.
view one, two or three sound pressure levels. Exceeding com.
levels are presented with a pre-warning amber or alarming
red color.
• The “Sound Level Predictor” visualizes the level history of Installation Instructions
the current measurement interval and indicates the head- • Register your XL2 and download the software from the sup-
room for the actual measurement period or the next few port page at https://my.nti-audio.com.
minutes. Green bars confirm that the present level is well be- • Unzip the file “XL2 Projector PRO Setup Vxx.zip“ on your
low limits. Red bars are a call to action to reduce the sound computer.
level at the mixing desk. This allows the FOH engineer to • Start the software installation and follow the instructions
optimize dynamic passages of the band for maximum audi- including driver installation.
ence satisfaction while still remaining within the legal limits. • Start the XL2 Projector PRO software.
• Start the XL2 Analyzer and connect it to the computer.

210
 XL2 Projector PRO

 The pop-up window USB Mode appears.

• Select COM port on the XL2.

• Microsoft Windows may recognize the new hardware au-
tomatically and start the hardware installation assistant. If
prompted, select “No connection to Windows Update” and
continue with the installation.
• Complete the installation.
For more details and features see the XL2 Projector PRO user
 XL2 Projector PRO displays the instrument screen in real- manual at ? in the menu.
time.

211
 Data Explorer Software

14. Data Explorer (optional)

Data Explorer is a PC-based software application with a pow- XL2 Data Explorer Permanent
erful data processor for easy and fast analysis of sound level The Data Explorer Option enables the import of logged sound
measurement data. It is dedicated to acoustic consultants and level data into the Data Explorer software, a PC-based soft-
noise measurement professionals. Data Explorer provides a ware application with a powerful data processor for easy and
convenient way to view, analyze and manage data and quickly fast analysis of noise monitoring data.
create customized reports.

Features of the Data Explorer software: Data Explorer 365

• Data visualization An annual subscription service for a XL2 Sound Level Meter is
• Fast zoom and pan offered alternatively to the permanently installed option.
• Audio playback synchronized to graph
• Markers with on-the-fly calculations
• Automated tonal and impulsive marker generation Supported operating systems
• Percentile levels Ln and Rating level Lr calculation • Windows XP SP3
• Customized Reporting • Windows Vista SP1 or later
• Windows 7, 8, 10, 11
Download the Data Explorer software from the XL2 Support
Page https://my.nti-audio.com.

212
Data Explorer Software

213
 Building Acoustics

15. Building Acoustics (optional)

The Sound Insulation Reporter software is a PC-based soft- XL2 Sound Insulation Permanent
ware application that provides all the standard reports for Air- The Sound Insulation Option enables the import of measure-
borne and Impact sound insulation measurements. Designed ment data into the Sound Insulation Reporter software.
for acoustic consultants, this comprehensive tool uses data
gathered by the XL2 Sound Level Meter, and quickly returns Sound Insulation Reporter 365
graphical analysis of all measurement positions. An annual subscription service for a XL2 Sound Level Meter is
offered alternatively to the permanently installed option.
Additionally, the software offers the ability to acquire real-time
data; two or more XL2 Sound Level Meters, may be controlled Supported operating systems
directly by the software. This allows simultaneous wireless • Windows Vista SP1 or later
measurement in both the sending and receiving room onsite; • Windows 7, 8.x, 10, 11
saving time. To enable this real-time acquisition of data, the
Sound Insulation Reporter software requires that the connect- Requirements
ed XL2s also have an activated Remote Measurement Option The measurement of the reverberation time in 1/3 octave band
installed. resolution requires the optional Extended Acoustic Pack in-
stalled on the XL2 Sound Level Meter.
Features:
• Airborne, Impact and Facade Sound Insulation Download the software from the XL2 Support Page at
• Customized Reporting https://my.nti-audio.com.
• Standards ASTM E336, ASTM E413, ASTM E1007, ASTM
E989, ASTM E966, ASTM E1332, BB93, DIN 4109, Document
E, GB/T 19889, ISO 16283, ISO 140, ISO 717, ISO 10140, NEN
5077:2019, SIA 181:2006, SIA 181:2020

214
Building Acoustics

215
 Room Acoustics

16. Room Acoustics (optional) • ASTM C423-17 - Sound Absorption

• ISO 354:2003 - Sound absorption in a reverberation room
The Room Acoustics Reporter is a PC software for automati-
cally generating reverberation time measurement reports and
analyzing the RTA frequency response spectrum. The software XL2 Room Acoustics Permanent
supports acousticians and experts in the visualization and de- The Room Acoustics Option enables the import of measure-
tailed evaluation of measurement data recorded with the XL2 ment data into the Room Acoustics Reporter software.
Sound Level Meter.
Room Acoustics Reporter 365
Features: An annual subscription service for a XL2 Sound Level Meter is
• Room acoustic simulation according to Sabine or Eyring offered alternatively to the permanently installed option.
• Import of own sound absorber database and tolerances
• Frequency response spectrum and Noise Curves Supported operating systems
• Windows Vista SP1 or later
The following standards are supported • Windows 7, 8.x, 10, 11
• IEC 61260: Octave-band and fractional-octave-band filters
• GB 50371 - Code for sound reinforcement system design Requirements
• ANSI/ASA S12.2-2019 - Noice criteria curves NC The measurement of the reverberation time in 1/3 octave band
• ANSI/ASA S12.2-2019 - Room noice criterion RNC resolution requires the optional Extended Acoustic Pack in-
• DIN 15996:2020 - Grenzkurven GK stalled on the XL2 Sound Level Meter.
• ISO R 1996-1971 - Noise rating curves NR
• ASR A3.7:2021 - Working Place Download the software from the XL2 Support Page at
• DIN 18041: 2016 - Acoustic quality in rooms https://my.nti-audio.com.
• ISO 3382-1:2009 - Reverberation time in performance spaces
• ISO 3382-2:2008 - Reverberation time in ordinary rooms
• ÖNORM B 8115-3:2015 - Room Acoustics

216
Room Acoustics

217
 Sound Power

17. Sound Power (optional)

Sound Power Reporter is a PC-based software application that XL2 Sound Power Permanent
provides all the standard reports for sound power measure- The Sound Power Option enables the import of measurement
ments in accordance with ISO 3744 and ANSI-ASA S12.54. data into the Sound Power Reporter software.

Designed for industrial professionals, this comprehensive tool Sound Power Reporter 365
uses data gathered by the XL2 Sound Level Meter, and quickly An annual subscription service for a XL2 Sound Level Meter is
returns graphical analysis of all measurement positions. offered alternatively to the permanently installed option.

Features of the Sound Power Reporter software: Supported operating systems

• Visualization of all measurement • Windows Vista SP1 or later
• Customized Reporting • Windows 7, 8.x, 10, 11
• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-ASA S12.51,
ANSI-ASA S12.54, ANSI-ASA S12.56 Requirements
The measurement of the reverberation time in one-third octave
Download the software from the XL2 Support Page at band resolution requires the optional Extended Acoustic Pack
https://my.nti-audio.com. installed on the XL2 Sound Level Meter.

218
Sound Power

219
 NoiseScout

18. Unattended Noise Monitoring

NoiseScout provides a comprehensive but easy-to-use 24/7
noise monitoring solution. Noise levels are recorded on-site by
the XL2 Sound Level Meter and are available for remote moni-
toring and download. NoiseScout is aimed at both short-term
noise assessments and long-term monitoring applications. It
offers the freedom to start and stop the remote noise monitor-
ing from your office or mobile device providing total flexibility
in meeting your project requirements.
XL2

Noise Monitoring in “Managed Mode”

During acquisition, audio recordings of the loudest periods and
automated email alerts allow noise issues to be addressed be-
fore a non-compliance condition arises. NoiseScout displays
the noise levels measured by the XL2 Sound Level Meter live
in your web browser. The measurement data recorded out in
the field is presented online in charts and dashboards. Multiple Managed Unattended Noise Monitoring
noise level meters can be monitored simultaneously within the
map view, thus providing localized geographic visualization for
all noise levels at a glance. Identified users can access all their
projects, control their monitors or create basic view modes, al-
lowing stakeholders to oversee their noise level data.

220
 NoiseScout

Noise Monitoring in “Gateway Mode”

Secure FTP Connection
Direct access to the XL2 Sound Level Meter is available from
around the world. An internet connection allows SFTP (Secure FTP Browser

File Transfer Protocol) and remote access to the XL2. All data
files can then be retrieved from the remote XL2 Sound Level 2017-03-16_SLM_000.XL2
2017-03-16_SLM_000_123_Report.txt
2017-03-16_SLM_000_123_Log.txt

Meter even during an ongoing measurement. Also, the spec-

2017-03-16_SLM_000_RTA_3rd_Report.txt
LAN 2017-03-16_SLM_000_RTA_3rd_Log.txt
2017-03-16_SLM_000_Audio_FS136.0dB(PK)_00.wav
Mobile
tral data and audio files can be directly downloaded from the
XL2
remote XL2.

The remote access allows full control of the XL2 Sound Level
Meter. All remote measurement commands available on the
XL2 are supported. For example, the current measurement
data may be captured in real time into a computer application,
XL2 Data Explorer
e.g. C#, MS Excel or LabView. You may program a customized USB

measurement application for remote sound level monitoring,

audio analysis or automated measurement tasks.
Remote Access to XL2 Sound Level Meter
NoiseScout operates also in a local network (intranet) without
internet connection.

221
 NoiseScout

How to connect?
1 Network Status Indication
The NetBox may be connected to the internet via mobile (3G, It replaces the speaker symbol in the top menu.
4G, 5G; 4G/5G using an external modem), LAN or Wi-Fi.
No network connection
The LAN connection is established automatically. Setup on the
XL2 is required for the 3G mobile and Wi-Fi connection. Network connection established

• Insert SIM card (not provided) into the NetBox Confirmation check mark indicates success-
• Connect the NetBox to the XL2 Sound Level Meter. ful on-going NoiseScout communication
• Select 1 and confirm with enter .

222
 NoiseScout

• Select Settings 2 and confirm with enter .

• Select Mobile Data and confirm with enter ; the minimum
requirement is entering the APN of your provider.

• Confirm Close.

 The XL2 is connected to the network.

• Set the connection parameters and select Exit.

223
 NoiseScout

Automated System Self-Test

The measurement microphone of a noise monitor is perma- One-Third Description Typical

nently exposed to the weather. This might impair the micro- Frequency Band reference spectrum
[Hz] [dB]
phone capsule and its performance. Therefore, NoiseScout
31.25 fundamental square wave 101.5
offers an automated system self-test (CIC). The complete sig- 100 harmonic 91.5
nal chain may be verified periodically, remotely, and without 160 harmonic 87.0
removing the microphone from site. Thus, precise sound level 200 harmonic 83.4
measurements are ensured. This test also produces an alarm 315 harmonic 82.2
400 harmonic 79.5
in case of any unexpected issues, like cable or microphone
defects. 500 harmonic 79.9
630 harmonic 78.4
800 harmonic 77.6
The automated system self-test is supported by the XL2 Sound 1000 fundamental square wave 100.9
Level Meter with the M2340 Measurement Microphone. The 3150 harmonic 91.5
microphone preamplifier has a built-in dedicated signal genera- 5000 harmonic 87.3
tor for the self-test, which is activated from NoiseScout via the 6300 harmonic 83.2
8000 harmonic 81.8
XL2 Sound Level Meter through the ASD communication. This 10000 harmonic 83.4
generator produces a square wave signal with the fundamen-
12500 harmonics 80.8
tal frequencies 31.25 Hz and 1000 Hz and the corresponding 16000 harmonics 80.9
harmonics for the self-test. The generated test signal spectrum 20000 harmonics 79.3
is measured by the XL2 and stored as a reference. Later on,
NoiseScout repeats the same test, e.g. daily, and the resulting
one-third octave spectrum is compared against the reference.

224
 NoiseScout

The maximum deviation in each frequency band is specified Self-Test Method

at 1 dB supporting the specified range of environmental con- The sysem self-test uses the charge injection
ditions. Unexpected issues, like cable defects, loose capsule check method, in short CIC. A dedicated square
mounting, or a missing microphone capsule cause a higher de- wave signal is capacitively coupled to the input
viation and trigger an automated alarm. of the MA230 Preamplifier and attenuated by
the capacitance of the microphone capsule.
High ambient noise may affect the self-test. Therefore, the
ambient noise level is measured prior to performing the self- Physical changes in capsules can influence
test. All is fine as long as the ambient noise effect is less than their capacitance, which ultimately leads to a
0.2 dB during the self-test – this requires the ambient noise changed level read from the test signal. The test
to be 13.3 dB below the reference spectrum of the self-test. signal passes through the preamplifier and the
High ambient noise levels will be reported in combination with cable to the XL2 Sound Level Meter for evalua-
a failed self-test. tion. This allows any changes in the microphone
capacitance, e.g. caused by damages of the mi-
crophone capsule or a loose capsule mounting
The following workflow is carried out by NoiseScout to be detected.
• Measure ambient noise level and compare result with refer-
ence spectrum Additional periodic manual calibration using a
• Generate 31.25 Hz square wave signal and measure actual Sound Calibrator is recommended in combina-
noise spectrum tion with a visual inspection of the noise moni-
• Generate 1000 Hz square wave signal and measure actual tor.
noise spectrum
• Compare results with the reference one-third octave spec-
trum

This workflow takes approximately 7 seconds.

225
 Time Synchronization

19. Time Synchronization

The XL2 Analyzer may synchronize the start time precisely with • Absolute time
the GPS signal. The measurement start matches the GPS time The XL2 receives the absolute time from the connected
with an accuracy of +/- 0.7 ms (+/- 32 samples @ 48 kHz). NetBox, which synchronizes to the NTP service. The XL2
time is synced every 60 seconds. The communication be-
This requires tween XL2 and NetBox causes an uncertainty in the timing
• a txt-file named “gpssync.txt” stored on the SD card in the two-digit milliseconds range.
• a specially adapted GPS Receiver, NTi Audio # 600 000 357
The combination of the relative and absolute timing allows the
Concept XL2 to start the measurement accurately. The GPS time signal
The measurement start follows these concepts: does not have to be permanently present on the XL2 during
the measurement, which accommodates the operation in case
• Relative Time of unfavorable GPS reception. It is important that the time sig-
The GPS Receiver generates a square signal with a frequen- nal was detected by the XL2 at least once before the start of
cy of 0.1 Hz. The rising edge is exactly synchronized to full the measurement, the XL2 then retains this time information
10 seconds. In other words, the positive edge of the signal with an accuracy of typically 0.5 ms per hour.
indicates the following: 00 – 10 – 20 – 30 – 40 – 50.

The square wave signal is available at the RCA input of the After repositioning the GPS receiver, the sys-
XL2 Analyzer. The instrument architecture offers two chan- tem takes about an hour to initialize for the first
nels, so it can simultaneously process the microphone signal time.
on the XLR input and the time signal on the RCA input.
After rebooting the XL2, or after changing the
Thanks to the GPS signal, the XL2 may precisely start every measurement function, the XL2 needs to syn-
10 seconds. chronize with GPS time again.

226
 Time Synchronization

XL2 User Interface Exactly 4 seconds before a full 10 second

time jump, the button changes and the mea-
The clock delimiter signals the state of GPS time detection. sured values and the timer value of the pre-
vious measurement are reset.

GPS time signal is synchronized with GPS The measurement begins exactly at the
(locked). 10-second jump.

GPS receiver connected, but time signal not

synced with GPS (unlock). Start without GPS
If the XL2 has not received a valid GPS information until the
GPS time signal not found, receiver is not start time, the internal XL2 time will be used as time. The XL2
connected or XL2 not configured for GPS. time is set by the NetBox.

If the NetBox has connection to the network before the start

When starting a GPS time-synchronous measurement you ob- time, then the time of NetBox is precisely synchronized via
serve the following characteristics: NTP. The start is precise to about 10 ms. If the NetBox could
not yet be provided with an exact time by NTP at the start, then
the NetBox time deviation is approx. 20 ppm since the last syn-
After starting the measurement, the start chronization (this corresponds to one error per day of
counter in the button will remain at 1 for up 24 hours * 3600 * 20 / 1e6 = 1.7 sec.
to 10 seconds.
As soon as the XL2 receives a valid time information via GPS,
the time deviation is logged in the log file.

227
 Time Synchronization

Minutes of deviation Example

The deviation of the time currently used for the measure- The PPS signal is recorded with the XL2. For this, the input of
ment from the GPS time is recorded by the XL2 in the log file the XL2 from XLR to RCA can be set. The positive edge of the
(123_Log.txt). recording should always be exactly to multiples of 10 seconds,
but in this case at 00: 35: 00,005:

Add_To_Time GPS Status

[ms] []

0.0 2.0

Meaning of the column “GPS Status”:

_123_log.txt:
0.0 No GPS signal detected at the RCA input 2017-10-05 09:49:58 00:34:58 -5.00 2.0 ---/---
2017-10-05 09:49:59 00:34:59 -5.00 2.0 ---/---
1.0 GPS signal detected but signaled UNLOCKED 2017-10-05 09:50:00 00:35:00 -5.00 2.0 ---/---
2017-10-05 09:50:01 00:35:01 -5.00 2.0 ---/---
2.0 GPS signal LOCKED (OK) 2017-10-05 09:50:02 00:35:02 -5.00 2.0 ---/---

In the log file, a correction value Add_to_Time of -5ms is re-

The deviation Add_To_Time can only be determined currently corded for this time position, so the corrected position of the
if the GPS status = 2 (locked). Otherwise, the last known er- pulse is: 00: 35: 00,005 + (-5ms) = 00:35:00.
ror is used for the current log line. The Add_To_Time column
indicates “-.-” in case that there was no GPS time recognized The state of the time synchronization can be seen in detail on
since the start of the device. the NoiseScout Gateway website.

228
 Time Synchronization

Connection Diagram

GPS Receiver connects to XL2 Adapter Cable MD6/RCA Adapter Cable MD6/USB connects to NetBox - USB 1

229
 Remote Measurement

20. Remote Measurement The commands are sent in ASCII format through the virtual
COM port to the XL2 Analyzer.
The Remote Measurement option allows the real-time acquisi-
tion of XL2 measurement data directly into a computer applica- Example Command Set
tion via USB. The option adds a real-time acquisition facility to INIT START
the Sound Insulation Reporter software. MEAS:INIT
MEAS:SLM:123? LAF
Alternatively you can write your own unique measurement ap- Result returned to PC: 53.8 dB,OK
plications for sound level monitoring or automated measure-
ments, e.g. with MS Excel or LabView. A documented com-
mand set for data retrieval via USB is available. The following The time the XL2 requires for a response depends on the com-
XL2 measurement functions are supported: mand and the workload of the XL2 (logging settings). A typical
• Sound level meter and spectrum analyzer SLMeter/RTA pattern for querying measurement data is:
• Vibration Meter VibMeter
• FFT Analyzer + Tol xl2.write(‹MEAS:INIT\n›)
• RT60 reverberation time xl2.write(‹MEAS:SLM:RTA:dt? EQ\n›)
• Audio analyzer RMS/THD+N result = xl2.readline()
• High-resolution RTA function 1/12 Oct + Tol
This pattern delivers a measurement result within:
The functionality of the Projector PRO option is included. • Min: 8 ms
• Mean: 10 ms
• Max: 35 ms
Order information:
Remote Measurement Option
NTi Audio #: 600 000 375 For more details you may download the dedicated Remote
Measurement Reference Manual.

230
 Remote Measurement

Auto Start
The XL2 with serial number ending “E0” or higher may power
on automatically upon after a power loss (e.g. mains power dis-
connected or battery pack empty) the power is available again.
Best the instrument is operated by mains power without the
internal battery pack installed. This auto start functionality is
enabled by copying a txt-file with the file name “AutoOn.txt”
onto the SD Card. This allows to remotely control the XL2 as
soon as power supply is available at the instrument.

231
 Microphones

21. Microphones
Overview Measurement Microphones

M2230 M2340 M2211 M2215 M4261 M2914

Certified Class 1 Certified Class 1 General purpose Measurement mi- Cost-effective High-performance
measurement measurement mi- measurement crophone for high class 2 measure- microphone
microphone crophone according microphone sound levels (up to ment microphone for acoustic mea-
in accordance with to IEC 61672, metal class 1 frequency 153 dB), for general sound surements of
IEC 61672, diaphragm, system response, class 1 frequency level testing and very low sound
metal diaphragm self-test (CIC) with metal diaphragm response, metal dia- service of audio- pressure levels
XL2 phragm acoustic installations

consists of MA220 consists of consists of consists of with permanently- requires ICP Adapter
PreAmplifier and MA230 PreAmpli- MA220 PreAmplifier MA220 PreAmplifier installed capsule ASD
MC230 or MC230A fier and MC230A and 7052 capsule and 7056 capsule
capsule capsule

232
 Microphones

Overview Outdoor Measurement Microphones

M2230-WP-90/-150 M2340-WP-90/-150 M4261-WP

Outdoor Microphone Outdoor Microphone Outdoor Microphone

Certified outdoor measurement Certified outdoor measurement Outdoor measurement microphone,

microphone, microphone, class 2 in accordance with IEC 61672
class 1 in accordance with IEC 61672 class 1 in accordance with IEC 61672,
system self-test (CIC)

consists of consists of consists of

M2230 Measurement Microphone M2340 Measurement Microphone M4261 Measurement Microphone
+ WP30 Weather Protection + WP30 Weather Protection + WP61 Weather Protection
with 90 mm or 150 mm windscreen with 90 mm or 150 mm windscreen with 90 mm windscreen

233
 Microphones

Overview Microphone Preamplifier

MA220 MA230
PreAmplifier PreAmplifier

Microphone preamplifier Microphone preamplifier

compatible with 1/2” pre-polarized capsules compatible with 1/2” pre-polarized capsules,
system self-test (CIC) with XL2 or XL3

234
 Microphones

The plug-on measurement microphones combined with the Electronic Data Sheet
XL2 Analyzer create a powerful sound level meter and a pro- The microphones include an electronic data sheet. The Auto-
fessional acoustic analyzer. The microphones are 48 VDC phan- mated Sensor Detection (ASD) of the XL2 Analyzer reads this
tom-powered and include an electronic data sheet. data, i.e. the microphone model and calibration data. This pro-
motes faster setup and ensures accurate measurements.

Integrated Preamplifier Screen connection used for

The microphone body contains a preamplifier that requires ASD technology
Microphone
48 VDC phantom power supply for operation. The microphones
combine high dynamic range and wide frequency range with XLR M
2

2
Pin 2 + 2
low noise. They can also be connected to the XL2 Audio and ASD Microphone
Pin 3 - 3 3

3
Capsule
Acoustic Analyzer using an ASD Cable for measurements at Pin 1 Shield 1 1

1
remote locations or for reduction of acoustic reflections.
Connection diagram of measurement microphones

XLR M
with electronic data sheet

Pin 1
Pin 2
Pin 3
Microphone plugs directly into the XL2
The XL2 automatically reads the electronic data sheet of the
connected microphone as follows:
• Connect the measurement microphone to the XL2.
• Switch on the XL2.

 The XL2 reads the electronic data sheet of the connected

microphone during a brief initialization process prior to the
first measurement.

235
 Microphones

Microphone Connection via the ASD Cable Microphone Connection via a professional Audio Cable
The NTi Audio measurement microphones can be connected For distances longer than 20 meter (= 65 feet) use a high-
to the XL2 Analyzer using an ASD Cable for measurements quality, low-capacitance standard professional audio cable. The
at remote locations or for reducing acoustic reflections. The microphone sensitivity has to be entered manually into the XL2
electronic data sheet is transmitted via the XLR connector’s Analyzer.
housing. Do not touch this during the brief initialization period
to ensure the complete data sheet is recognized by the XL2. Alternatively connect the microphone first directly to the Ana-
The automated sensor detection does not disturb any mea- lyzer. The XL2 reads the sensitivity and remembers this value.
surements. You may join 5 or 10 meter ASD Cables together in Afterwards connect the audio cable.
series. The ASD technology supports accurate data communi-
cation up to a combined cable length of 20 meters (= 65 feet).
• Use the microphone for the intended
purpose only.
• Protect the microphone from contamination
by always using the supplied windscreen.
• Never use the microphone in a damp or wet
environment.
• Do not jar or drop the microphone.
• Do not remove the microphone protective grid.
• Do not touch the microphone membrane.
• Remove the black dust cap of the 1/2”
measurement microphones prior to use.
• In an outdoor environment, ensure that you
install protection against lightning strikes.

236
 Microphones

Outdoor Measurement Microphones

The Outdoor Measurement Microphones offer a weather-pro- Inside:
tected measurement solution for the XL2 Sound Level Meter Protection Cage with
Bird Spike BS01
allowing acquisition of environmental noise data in outdoor ap- water-repellent
#600 040 062
membrane
plications. The corrosion-free polymer housing, wind screen,
WP30 #600 040 064
water-repellent membrane and bird spike provide excellent pro- WP61 #600 040 081
tection from rain, wind, dust and perching birds.

Outdoor Measurement Microphone Types Inside:

• M2230-WP: M2230 Measurement Microphone + 90 mm
Measurement Wind Screen
WP30 Weather Protection Microphone #600 040 061
• M2340-WP: M2340 + WP30 Weather Protection
• M4261-WP: M4261 + WP61 Weather Protection
Fixing Screw
M5 x 6 mm Upper
Body Part
#150 000 048
• Do not install the Outdoor Measurement Mi-
crophones in horizontal direction. Raindrops Lower
may damage the measurement microphone. Body Part
• The snap mechanism works only at tempera- #150 000 047
tures above -15°C / 5°F (as the O-Ring stiff-
ens). In colder conditions we suggest you
Tripod
warm up the housing first, e.g. with your O-Ring Replacement Set Mounting Plate
hands. #600 040 069 #600 040 072

237
 Microphones

The Outdoor Measurement Microphones M2230-WP and

M2340-WP fulfill the Class 1 requirements according to Always activate the applicable frequency cor-
IEC 61672 and ANSI S1.4 for vertical sound incidence. For com- rection filter in the XL2. The filter ensures
pliance with horizontal sound incidence a spectral correction is that the measurements accuracy meets the
employed in the associated XL2 Sound Level Meter. class 1 requirements of IEC 61672 and
ANSI S1.4.
Alternatively the Measurement Microphone M2211 or M2215
can be fitted into the Weather Protection WP30. These micro-
phones have to be pushed further into the upper body by 3
mm. The top part of the capsule has to be 13 mm above the
upper body housing of the WP30. This is required because the
M2211 and M2215 capsule is 3 mm shorter than the default
M2230 microphone capsule.

The Outdoor Measurement Microphone M4261-WP fulfills the

Class 2 requirements according to IEC 61672 and ANSI S1.4.
It consists of an M4261 Microphone and the WP61 Weather
Protection. For compliance with horizontal sound incidence a
spectral correction is employed in the associated XL2 Sound
Level Meter.

238
 Microphones

Assembling Insert Measurement Microphone

• Connect the measurement microphone to the female XLR
This chapter describes how to install the Measurement Micro- of the ASD Cable.
phone into the weather protection kit: • Insert the measurement microphone into the upper body
tube so that the bottom end of the microphone is in line
Install ASD Cable with the bottom end of the upper body tube. Align the fixing
• Feed the female XLR of the ASD Cable through the bottom screw hole of the upper body tube with the lower screw of
of the lower body tube. the measurement microphone (remove the fixing screw to
• Attach the footer plate to the lower body tube using the see the lower screw head through the fixing screw hole).
three allen screws, feeding the cable through the side slot
of the footer plate.

Fixing Screw Hole

Lower screw of
measurement
microphone

239
 Microphones

Attach the Microphone to the Upper Body Tube Assemble the Weather Protection Body
Attaching the fixing screw of the upper body tube onto the Retract the ASD cable through the lower body tube and screw
lower screw of the measurement microphone ensures that the the lower body tube to the upper tube, ensuring that the cable
microphone housing is not scratched. does not twist during this operation.

• Insert and gently tighten the fixing screw while jiggling the
microphone. You will feel the fixing screw center in the head
of the lower screw of the microphone. Do not over tighten
the fixing screw.
• Again verify that the bottom end of the inserted microphone is
in line with the bottom end of the upper body tube.

In Line

240
 Microphones

Mount the Top Section Calibration

The top section of the weather protection kit consists of the
wind screen, the enclosed protection cage with water-repel- The design of the Outdoor Measurement Microphone sup-
lent membrane and the bird spike. Gently slide the top section ports easy calibration of the microphone. To calibrate, follow
over the microphone tip and on to the upper body tube. You will the procedure below:
feel a slight increase in resistance approximately 3 mm before
the top section’s final position. Slightly increase the pressure • The top section of the Outdoor Microphone is snapped
until the top section snaps into the final position with an au- on to the body tube. Remove the top section of the Out-
dible click. door Microphone by gently pulling the bird spike upwards.
At the same time gently push up on the cage inside the
wind screen with two fingers of your other hand. You will
feel when the snap mechanism is released.
Gently remove the top section.
Pull

Push
 You have successfully assembled the Outdoor Measure-
ment Microphone.

241
 Microphones

• Calibrate the microphone as described in the XL2 user man-

ual using the NTi Audio Precision Calibrator. • The outdoor windscreen is recommended to be
replaced annually. The “WP30-90/WP61 Wind-
screen Replacement” includes two 90 mm
spare windscreens, NTi Audio # 600 040 061.
The “WP30-150 Windscreen Replacement”
includes two 150 mm spare windscreens,
NTi Audio # 600 040 095.
• The water-repellent membrane in the top sec-
tion is mounted with two O-Rings. Inspect
these O-Rings (13x1 mm) and the membrane
annually for proper seating and good condi-
tion. Do not touch the water-repellent mem-
brane.

• Snap the top section back into position on the body tube.

 You have successfully calibrated the Outdoor Measure-

ment Microphone.

242
 Microphones

Disassembling the Top Section Capsule Replacement Instruction

• The top section is snapped on to the body tube. Remove The microphones for the XL2 Analyzer include an electronic
the top section by gently pulling the bird spike upwards. At data sheet. The Automated Sensor Detection (ASD) of the XL2
the same time gently push up on the cage inside the wind Analyzer automatically reads this data, i.e. the microphone
screen with two fingers of your other hand. You will feel model and calibration data. This promotes faster setup and en-
when the snap mechanism is released. sures accurate measurements. In case of a capsule replace-
• Gently remove the top section and turn the top section up- ment, the electronic data sheet needs to be updated with the
side down and hold it by the bird spike. data of the new capsule.
• Gently unscrew the cage from the hole of the wind screen.
Do not touch the water-repellent membrane!
• Assemble in reverse order. Step-by-Step-Instruction
• Install the new capsule on the microphone preamplifier.
• Plug the measurement microphone directly into the XL2.
• Install the latest firmware in the XL2, available at
https://my.nti-audio.com/support/xl2.
• Start the XL2 Projector PRO Software. The computer re-
quires online connection to the web.
• Connect the XL2 with the USB cable to the Projector PRO
software, thus you see the XL2 display live on the computer
monitor. (if prompted select COM-Port on the XL2)
• Press the computer keyboard keys “Ctrl + Shift + F5” at the
same time (alternatively “Ctrl + Alt + F5”)

243
 Microphones

• Select Original NTi Audio Microphone or Custom micro-

phone.

• Case: Original NTi Audio Microphone

- Enter the serial number of the new capsule
- Confirm by clicking Write to MA220.
- Now XL2 reads the factory sensitivity of the new capsule
from the NTi Audio server and stores the new data into
the electronic data sheet of the preamplifier. You will be
prompted if all is in good order.

• Case: Custom microphone

- Enter the microphone sensitivity
- Confirm by clicking Write to MA220.
- Now XL2 stores the microphone sensitivity as factory sen-
sitivity in the electronic data sheet of the MA220 PreAm-
plifier.

• Verify the setting in the “CALIBRATE” screen of the XL2 and

perform a user calibration to verify if the new capsule works
in good order.

244
Microphones

245
 Further Information

22. Further Information Tips and Troubleshooting

Overview
My NTi Audio • Resetting to Factory Default
• XL2 Starts Up with Limited Functions
Register your instruments at My NTi Audio and benefit from • Can I use another SD Card?
the following possibilities: • Formatting the SD Card
• SD Card Errors
• Free updates for your instruments • Error messages on display
• Activation of optional product functions • Stored Data or Wav-files not available on SD Card
• Premium access to downloads • Date and Time Lost
• Receive application and product news
• Faster worldwide support
• Tracing support in case of loss or theft
• Calibration support Resetting to Factory Default
If the XL2 Audio and Acoustic Analyzer reacts unexpectedly, a
How to Register reset to the factory settings might solve the problem.
• Open the web page “https://my.nti-audio.com”.
• You are prompted to login or create your My NTi Audio • Switch off the XL2 .
account. • Hold down escape and simultaneously operate On/Off
• The web page “My NTi Audio Products” opens. .
• Select the product type and enter the serial number.
• Confirm with “Register”.  The XL2 starts up and the reset confirmation is displayed.
• Now your product is listed in the table “My Products“.

 Congratulations, your NTi Audio product is registered

246
 Further Information

XL2 Starts Up with Limited Functions SD Card Errors

The XL2 has been operated the last time in one of the sim- The XL2 Audio and Acoustic Analyzer writes measurement
plified application profiles and the system settings have been data automatically onto the SD Card during ongoing measure-
changed as follows: Select Profile from Yes to No. ments, thus a functioning SD Card has to be inserted at all
times.
• Follow the above resetting to factory default.
Error Messages Actions to do
 The XL2 will start up with full functionality.
Missing SD-Card Insert the SD Card.

Can I use another SD Card? SD-Card is not FAT Format the SD Card on the PC. Follow
Yes, you can use any alternative SD Card, such as offered in the formatted the instructions at Formatting the SC
chapter Further Information: Accessories. Card in this chapter.
• Switch off the XL2 .
• Insert the SD Card into the XL2 Analyzer. SD-Card is full The memory of the SD Card is full.
• Switch on the XL2 . Download all data to the PC and emp-
ty the SD Card.
 The XL2 writes the data structure automatically to the in-
serted SD Card.
Other Error Messages on Display
In case error messages, such as Error 900, Error 901, ..., is
Formatting the SD Card shown on the XL2 display , then follow “Resetting to Factory
In case you need to format the SD Card, then we recommend Default” in this chapter. These error messages describe a com-
doing so utilizing the software SDFormatter. This software en- mon status information and are not associated with a dedicat-
sures the best performance of your SD Card. SDFormatter is a ed issue. If such errors occur frequently, then kindly report the
free download at www.sdcard.org/downloads. full error message back to NTi Audio for resolution. Thank you.

247
 Further Information

Stored Data or Wav-files not available on SD Card Date and Time Lost
The file system might be corrupted. The XL2 Analyzer has a small internal battery installed. This
• On the PC, right-click on the “NTi Audio XL2” drive, select powers the real time clock (RTC), and ensures the accurate
“Properties” and click “Check Now” as shown below. display of the date and time on the instrument and in the mea-
• Thereafter all stored data should be available again. surement reports, even if the device has been powered down
for a period of time. This, so called, RTC battery is soldered on
to the internal circuit board. The typical battery lifetime is 8-9
years.

Kindly return the instrument for service. For convenience, this

service may be combined with the recommended annual cali-
bration of the XL2 Sound Level Meter.

248
 Further Information

Firmware Update
You will find information about the installed firmware ver- Firmware update with XL2 in hand, PC online:
sion in the systems settings of the instrument. The firm- • Start the XL2 and connect it to the PC.
ware revision history is listed on the XL2 Support Page • The XL2 displays the pop-up window USB Mode.
https://my.nti-audio.com. • Select Mass storage. The PC thus recognizes the XL2 as a
mass storage device.
Updating the firmware on the XL2 is executed by placing the • Double-click the file XL2.htm 1 . The web screen “XL2 In-
XL2Vxxx.xx file in the root directory of the XL2. When started, strument Status“ opens.
the XL2 automatically completes the firmware update. • Select “Look for FW Updates“. The web screen “XL2 Sup-
port Page“ opens.
• Compare the firmware version to the latest version avail-
able.
• If an update is required, download and save the firmware
file XL2Vxxx.xx into the XL2 root directory (the root direc-
tory shows the folders “Projects”, XL2_SYS”, the file
“xl2.htm” and others).
1 • Remove the USB cable and power up the XL2 .
• Watch the display and wait until the update is finished.
• All settings are back to factory default. Adjust the display and
1 XL2.htm reporting settings according your requirements.
This file opens the XL2 instrument status page, for online
• Firmware updates
• Activation of options No PC available
If you have no web access at all, please contact the local NTi
Audio partner.

249
 Further Information

Options • FFT function

- High-resolution Zoom-FFT with selectable frequency
The System menu shows the installed options on the XL2. ranges and resolution up to 0.4 Hz in the range of 5 Hz to
The following options extend the measurement functions of 20 kHz
the XL2: - Recording of linear wav-files (24 bit, 48 kHz)
• RT60 function
Extended Acoustic Pack - Reverberation time in 1/3 octave resolution
NTi Audio #: 600 000 339 • 1/12 octave Spectral Analyzer
(requires Spectral Limits Option)
The Extended Acoustic Pack offers the following additional fea- - Recording of linear wav-files (24 bit, 48 kHz)
tures for sound level- and acoustic measurements.

• SLMeter/RTA function
- Recording of linear wav-files (24 bit, 48 kHz)
- Percentiles for wide band and spectrum with flexible set- Projector PRO Option
ting from 0.1% to 99.9% NTi Audio #: 600 000 439
- Sound Exposure Level LAE
- 100 ms logging The Projector PRO option enables the following two additional
- RTA logging of Lmin and Lmax functions to the Projector PRO software:
- Event-triggered audio and data recording • “XL View” for large screen dB level display
- Time weighting: Impulse (LxI, LxIeq with x= A, C, Z) • “Sound Level Predictor” that indicates the headroom for the
- True peak level in 1/1 and 1/3 octave resolution next few minutes during live sound mixing
- Clock-impulse maximum level (TaktMax) in accordance
with DIN 45645-1 and DIN 45657
- Impulsiveness detection in accordance with BS4142:2014
and NordTest ACOU 112

250
 Further Information

Speech Intelligibility STIPA Remote Measurement Option

NTi Audio #: 600 000 338 NTi Audio #: 600 000 375

The XL2 Analyzer measures the speech intelligibility accord- The Remote Measurement option allows the real-time acquisi-
ing to the latest revision of standard IEC 60268-16:2020 tion of XL2 measurement data directly into a computer applica-
(edition 5) and older editions. It includes ambient noise cor- tion via USB. The option adds a real-time acquisition facility to
rection and automated averaging of measurements. The XL2 the Sound Insulation Reporter software.
displays the measurement results as STI or as CIS results, ac-
companied by the individual levels and modulation indices of Alternatively you can write your own unique measurement ap-
the seven octave bands. plications for sound level monitoring or automated measure-
ments, e.g. with MS Excel or LabView. A documented com-
The measurement results are acquired from the dedicated mand set for data retrieval via USB is available. The following
STIPA test signal source: XL2 measurement functions are supported:
• NTi Audio TalkBox, acoustic signal generator • Sound level meter and spectrum analyzer SLMeter/RTA
required for audio systems with voice microphones, thus • Vibration Meter VibMeter
measuring the complete signal chain • FFT Analyzer + Tol
• Minirator MR-PRO, test signal generator • RT60 Reverberation time
required for audio systems with line inputs • Audio analyzer RMS/THD+N
• Other Audio Players • High-resolution RTA function 1/12 Oct + Tol
Register the XL2 and download the STIPA test signal at
https://my.nti-audio.com/support/xl2 The Remote Measurement Option includes the functionality
available in the Projector PRO option.

251
 Further Information

Spectral Limits Option

NTi Audio #: 600 000 376

The Spectral Limits Option extends the XL2 function range in • FFT Analyzer
both, the sound and vibration mode. It adds noise curves, trace High-resolution Zoom-FFT with selectable frequency ranges
capturing, relative curve display and comprehensive tolerance and resolution up to 0.4 Hz in the range of
handling for the FFT Analysis and high-resolution spectral anal- - Sound mode: 5 Hz to 20 kHz
ysis up to 1/12th octave. The vibration mode is enabled upon - Vibration mode: 1 Hz to 20 kHz
installing the vibration option. • Sound Level Meter
True peak level in 1/1 and 1/3 octave resolution (disabled with
type approved firmware)
• FFT and 1/12 octave Analyzer • Noise Curves
- Capturing of multiple readings into the internal memory In accordance with ANSI S12.2-2019, -1995 and ISO 1996
- Comparing measurement results against captures with
relative or absolute curve display
- Comprehensive tolerance handling with tolerance masks
based on captures for passed/failed measurements
• 1/12 octave Spectral Analyzer
- High-resolution spectral analyzer 1/12 Oct + Tol
- Selectable 1/1, 1/3, 1/6 and 1/12 octave resolution
- Frequency band listening at rear speaker
- Sound Mode: 11.5 Hz to 21.8 kHz
- Vibration mode: 0.73 Hz to 1.36 kHz

252
 Further Information

Type Approval Option XL2 Vibration Option

NTi Audio #: 600 000 377 NTi Audio #: 600 000 436

The Type Approval Option upgrades the instrument to the The Vibration Option turns the XL2 Analyzer into a professional
XL2-TA, the sound level meter dedicated to certified mea- vibration meter with broadband measurements and spectral
surements. The XL2-TA with the M2230 microphone forms analysis in 1/3 or octave resolution. The XL2 Vibration Meter
a type approved sound level meter offering class 1 per- determines vibration acceleration, velocity and deflection with
formance in accordance with IEC61672, IEC61260 and standard-compliant weighting filters in the frequency range
ANSI S1.4. from 0.8 Hz to 2.5 kHz. Detailed recording of measurement
data and audio files allow for comprehensive evaluation and
The Type Approval Option includes reporting. In addition, the XL2 Vibration Meter comes standard
• XL2-TA Firmware V4.71 (approved Firmware) with an FFT analysis and an oscilloscope function. Selectable
• Sticker XL2-TA FFT frequency ranges from 1 Hz to 1.69 kHz allow a detailed
• XL2-TA Manual (available online at www.nti-audio.com/XL2) examination of the measured vibrations.

How do I get my XL2-TA ready for accreditation? The Spectral Limits Option adds functions to the Vibration Me-
• Install the Type Approval Option on the XL2 and apply the ter including a zoom FFT up to 20 kHz and a 1/12 octave band
XL2-TA sticker on top of the XL2 label on the display. analysis from 0.73 Hz to 1.36 kHz. Also, it adds the ability to
• Download the dedicated firmware for accreditation to your record reference spectra and set tolerances for pass / fail qual-
XL2 from the XL2 Support Page at https://my.nti-audio.com. ity control measurements. The Remote Measurement Option
• After the firmware installation, the XL2-TA starts with a pop- allows the real-time acquisition of measurement data directly
up window “XL2 Type Approved SLM/RTA“.The sound level into a computer application via the USB interface. A document-
meter function SLM/RTA may be accredited now. ed command set is available.

The type approved firmware deactivates the X-Curve in the The Vibration Option is supported by the XL2 with firmware
SLM function and the unit SPL in the RMS/THD+N function. V4.11 or higher.

253
 Further Information

Cinema Meter Option • Create new cinema

NTi Audio #: 600 000 379 Generates measurement templates according the cinema
size with dedicated X-curve selection.
The Cinema Meter Option forms the dedicated solution • Calibrate cinema
for efficient calibration and repetitive verification of cinema Calibration menu for reference data recording of each chan-
loudspeaker systems according to the SMPTE ST 202:2010, nel as well as headroom tests and averaging measurement
SMPTE RP 200:2012 and ISO 2969:2015 standards. An interac- results of different microphone positions
tive assistant guides the user through dedicated measurement • Verify Cinema
procedures. Verification menu for periodical cinema measurements and
comparison against the reference data
• Lock into Verify Mode
Locks the XL2 Analyzer in the Verify Cinema mode. After
powering off the instruments starts up directly in the Verify
Mode again. The user may unlock the instrument anytime.
• View verification results
Displays measurement deviations of periodical measure-
ment against reference data.
• Exit
Returns back to other XL2 measurement functions.

The Cinema Meter Option consists of

• Spectral Limits Option
NTi Audio # 600 000 376
• Cinema Assistant Option
NTi Audio # 600 000 378

254
 Further Information

XL2 Data Explorer Option XL2 Sound Insulation Option

NTi Audio #: 600 000 430 NTi Audio #: 600 000 432

The Data Explorer Option enables the import of logged sound The Sound Insulation Option enables the import of measure-
level data into the Data Explorer software, a PC-based soft- ment data into the Sound Insulation Reporter software.
ware application with a powerful data processor for easy and
fast analysis of noise monitoring data. Sound Insulation Reporter is a PC-based software application
that provides all the standard reports for Airborne, Impact and
Visualize, analyze and control millions of data points with this Facade sound insulation measurements. Designed for acous-
tool that is dedicated to acoustic consultants and noise mea- tic consultants, this comprehensive tool uses data gathered
surement professionals. It provides a convenient way to view by the XL2 Sound Level Meter, and quickly returns graphical
and manage your data and quickly create customized reports. analysis of all measurement positions.

Features of the XL2 Data Explorer software: Features of the Sound Insulation Reporter software:
• Data visualization • Airborne, Impact and Facade Sound Insulation
• Fast zoom and pan • Visualization of all measurement data
• Audio playback synchronized to graph • Customized Reporting
• Markers with on-the-fly calculations • Standards ASTM E336, ASTM E413, ASTM E1007, ASTM
• Automated tonal and impulsive marker generation E989, ASTM E966, ASTM E1332, BB93, DIN 4109, Docu-
• Percentile levels Ln and Rating level Lr calculation ment E, GB/T 19889, ISO 16283, ISO 140, ISO 717, ISO
• Customized Reporting 10140, NEN 5077:2019, SIA 181:2006, SIA 181:2020

Data Explorer 365 Sound Insulation Reporter 365

NTi Audio #: 600 000 431 NTi Audio #: 600 000 433
Annual subscription service for one XL2 Sound Level Meter. Annual subscription service for one XL2 Sound Level Meter.

255
 Further Information

XL2 Room Acoustics Option

NTi Audio #: 600 000 440

The Room Acoustics Option enables the import of measure- The following standards are supported
ment data into the Room Acoustics Reporter software. • IEC 61260: Octave-band and fractional-octave-band filters
• GB 50371 - Code for sound reinforcement system design
The Room Acoustics Reporter is a PC software for automati- • ANSI/ASA S12.2-2019 - Noice criteria curves NC
cally generating reverberation time measurement reports and • ANSI/ASA S12.2-2019 - Room noice criterion RNC
analyzing the RTA frequency response spectrum. The software • DIN 15996:2020 - Grenzkurven GK
supports acousticians and experts in the visualization and de- • ISO R 1996-1971 - Noise rating curves NR
tailed evaluation of measurement data recorded with the XL2 • ASR A3.7:2021 - Working Place
Sound Level Meter. • DIN 18041: 2016 - Acoustic quality in rooms
• ISO 3382-1:2009 - Reverberation time in performance spaces
Features: • ISO 3382-2:2008 - Reverberation time in ordinary rooms
• Room acoustic simulation according to Sabine or Eyring • ÖNORM B 8115-3:2015 - Room Acoustics
• Import of own sound absorber database and tolerances • ASTM C423-17 - Sound Absorption
• Frequency response spectrum and Noise Curves • ISO 354:2003 - Sound absorption in a reverberation room

Room Acoustics Reporter 365

NTi Audio #: 600 000 441
Annual subscription service for one XL2 Sound Level Meter.

256
 Further Information

XL2 Sound Power Option

NTi Audio #: 600 000 434

The Sound Power Option enables the import of measurement

data into the Sound Power Reporter software.

Sound Power Reporter is a PC-based software application that

provides all the standard reports for sound power measure-
ments. Designed for industrial professionals, this comprehen-
sive tool uses data gathered by the XL2 Sound Level Meter,
and quickly returns graphical analysis of all measurement posi-
tions.

Features of the Sound Power Reporter software:

• Visualization of all measurement
• Customized Reporting
• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-ASA S12.51,
S12.54, S12.56

Sound Power Reporter 365

NTi Audio #: 600 000 435
Annual subscription service for one XL2 Sound Level Meter.

257
 Further Information

Installation of Options
1.

3.

2. PC
Power On XL2
Mass storage

6.
5.
4.

1.

Open XL2-TA.htm Activate option Login

(https://my.nti-audio.com)

258
 Further Information

8.
7.

Insert License number Get Activation Key

9.

10.

Download activation file and copy to XL2 (xx_0xxxx.txt)

259
 Further Information

Accessories Mains Power Adapter

Mains Power Adapter the XL2 Audio and
Manufacturer Calibration Certificate Acoustic Analyzer with removable plug
Calibration The calibration certificate lists the individ- types. The Mains Power Adapter suits the
Certificate
ual product data with serial number. The typical power sockets in Australia, China,
calibration and adjustment procedures Europe, Japan, US and UK.
follow the documentation and traceability NTi Audio #: 600 000 333
requirements of the EN ISO / IEC 17025
standard. Annual re-calibration of the in- Spare Li-Po Battery
strument is recommended ensuring ac- Rechargeable spare battery for portable
curate measurements. measurements at any time.
NTi Audio # 600 000 018 NTi Audio #: 600 000 337

Ever-ready Pouch ICP Adapter ASD

The Ever-ready Pouch protects the XL2 The ICP Adapter connects to the XL2 and
during transport and operation. With its generates ICP power supply for acceler-
convenient belt-clip, the XL2 can be kept ometers and other custom sensors. The
close-by for those tasks requiring both adapter offers an electronic data sheet,
hands. The Ever-ready Pouch allows oper- which stores the sensitivity and individual
ation of the XL2 while fitted in the pouch. serial number of the connected sensor.
NTi Audio #: 600 000 335 NTi Audio #: 600 010 223
ICP is a registered trademark of PCB Piezotronics.

260
 Further Information

XLR Adapter ASD Battery Charger

XLR male/female Adapter with electronic The Battery Charger efficiently recharges
data sheet for automated sensor detec- the spare battery whilst you are using
tion (ASD) of other sensors. The adapter is your XL2 Audio and Acoustic Analyzer.
available in two variations: The type ASD- One spare Li-Po battery is included with
2 is used for measurement microphones the battery charger.
with isolated housing ground connection NTi Audio #: 600 000 332
and the type ASD for induction loop and
other sensors. XL2 Mounting Adapter
This mechanical adapter piece mounts
NTi Audio #: the XL2 on a microphone stand. Adapters
• XLR Adapter ASD: 600 000 383 for 3/8” or 5/8” stands are included.
• XLR Adapter ASD-2: 600 000 385 NTi Audio #: 600 000 372

System Case Ball Head Mount

This compact system case provides the This flexible universal joint mounts the
professional transport protection for work XL2 on a 1/4” or 3/8” stand. It provides
in the field. It offers space for the hand- the facility to mount the XL2 at any an-
held instruments, cables and connectors. gle.
NTi Audio #: 600 000 701 NTi Audio #: 600 000 387

A 5/8” stand requires additionally the

Mounting Adapter, # 600 000 372.

261
 Further Information

Digital I/O Adapter PCB ASD Cable

The Digital I/O Adapter serves to control The ASD Cable allows for extended con-
I/O external peripheral devices, such as indi- nections of the NTi Audio measurement
cating sound levels that exceed limits on microphones. It supports the transfer of
a big external red-orange-green lamp. It the electronic data sheet from the micro-
connects to the digital I/O interface. phone to the XL2 Analyzer.
NTi Audio #: 600 000 380 NTi Audio #:
• 5 meter (16 foot): 600 000 336
XL2 Input Keypad • 10 meter (32 foot): 600 000 364
The XL2 Input Keypad offers four marker • 20 meter (64 foot): 600 000 365
keys to trigger an event recording or cat-
egorize any noise during measurements. The ASD technology for the electronic
Requires the optional Extended Acoustic data sheet transfer is applicable for a ca-
Pack. ble length of up to 20 meters (64 feet).
NTi Audio #: 600 000 384

262
 Further Information

STARQUAD cable
with low capacitive load NetBox
The NetBox connects the XL2 Sound
1 1
Level Meter to the internet for unat-
2 2 tended noise monitoring. It transfers the
measurement data to the fully-managed
3 3 NoiseScout Web Portal in real time or
provides a secure internet FTP access to
ASD
the instrument. The noise monitor may
Housing Housing be connected via 3G, 4G, 5G, LAN or
do not connect
Wi-Fi (an external modem is required for
Capacity between ASD line to shield total < 2.7nF 4G/5G).

NTi Audio #:
• NetBox (LAN & Wi-Fi): 600 000 450
• NetBox with 3G-Modem, LAN & Wi-Fi:
ASD Flat Ribbon Cable 1m 600 000 458
Microphone cable for passing closed win- • NoiseScout 365
dows or doors. It supports the transfer of (subscription service for one year)
the electronic data sheet from the micro- or Data Credits
phone to the XL2 Analyzer. - 30 Days: 600 000 490
NTi Audio #: 600 000 367 - 100 Days: 600 000 491
- 366 Days: 600 000 492
- 1096 Days: 600 000 493

263
 Further Information

4G/LTE Gateway WP30 Weather Protection

The 4G/LTE Gateway is a small, light- Protect your measurement microphones
weight, and energy-efficient industrial M2230 and M2340 from rain, wind, dust
gateway equipped with mission-critical and perching birds with this professional
LTE capabilities, Gigabit Ethernet inter- outdoor weather protection kit. Ideal
face, digital Inputs/Outputs, and micro- for precise acquisition of environmental
USB port. noise data in outdoor applications.
This 4G/LTE Gateway has been specially
selected for use with the XL2 Sound Lev- Features
el Meter. It connects XL2+NetBox to the • Class 1 compliant with IEC 61672 and
internet for remote monitoring of noise ANSI S1.4 for vertical and horizontal
levels. sound incidence
• Protection from rain and dust (IP54),
NTi Audio #: wind and perching birds
• 600 076 011 • Built from corrosion-free materials
4G/LTE Gateway for NetBox • Removable top section for easy micro-
(worldwide excluding Americas, China, phone calibration
Japan) • Standard 3/8” tripod mount
• 600 076 012 • Weight: 270 g (9.5 oz.)
4G/LTE Router for NetBox • Optional Pole Mount Adapter
(worldwide) • Optional sturdy outdoor carrying case
available

NTi Audio #:
• 600 040 060 (WP30-90)
• 600 040 090 (WP30-150)

264
 Further Information

WP61 Weather Protection for M4261 Pole Mount Adapter

Protect your M4261 microphone from The outdoor measurement microphone
rain, wind, dust and perching birds with may be installed on a pole using this
this professional outdoor weather protec- adapter. The microphone is connected to
tion kit. the sound level meter by the ASD cable,
which runs through the pole and the
Features adapter to the microphone. The adapter
• Class 2 compliant with IEC 61672 and is available in two different sizes.
ANSI S1.4 for vertical and horizontal
sound incidence NTi Audio #:
• Protection from rain and dust (IP54), • 600 040 067
wind and perching birds Pole Mount Adapter PM 1”
• Built from corrosion-free materials supports pole diameter 25 - 33 mm
• Removable top section for easy micro- (1-1.3”)
phone calibration • 600 040 068
• Standard 3/8” tripod mount Pole Mount Adapter PM 1 1/4”
• Weight: 270 g (9.5 oz.) supports pole diameter 32 - 44 mm
• Optional Pole Mount Adapter (1.25-1.75”)
• Optional sturdy outdoor carrying case
available

NTi Audio # 600 040 080

265
 Further Information

Limit Light Class 1 Sound Calibrator

The XL2 Audio and Acoustic Analyzer in The battery-operated Class 1 Sound
combination with this Limit Light offers Calibrator is classified for the calibration
a turnkey solution for live sound monitor- of class 1 measurement microphones,
ing. The sound level limits are set in the sound level meters and other acoustic
XL2. The Limit Light provides a pre-warn- measurement equipment. This precision
ing with an orange light and indicates that microphone calibrator delivers 94 or 114
levels have been exceeded with a red dB at a frequency of 1 kHz.
light. NTi Audio #: 600 000 388
NTi Audio #: 600 000 600
The optional 1/4” adapter ADP-1/4-P is
Stack Light required to fit 1/4” measurement micro-
The XL2 Audio and Acoustic Analyzer in phones.
combination with this Stack Light pro- NTi Audio #: 600 000 391
vides a turnkey solution for noise level
monitoring or passed / failed measure- Class 2 Sound Calibrator
ments where a prominent visual indica- The battery-operated Class 2 Sound
tion is required. The Stack Light connects Calibrator is classified for the calibration
directly to the XL2 Analyzer and shows of class 2 measurement microphones,
the actual measurement result with three sound level meters and other acoustic
different colors; green, orange and red. measurement equipment. This micro-
NTi Audio #: 600 000 610 phone calibrator delivers 114 dB at a fre-
quency of 1 kHz.
NTi Audio #: 600 000 394

266
 Further Information

Weatherproof Enclosure for Basic Outdoor Case

Noise Monitoring Terminal The Basic Outdoor Case is a simple and ef-
The weatherproof enclosure is the tai- ficient solution for outdoor noise monitor-
lored fixed installation solution for unat- ing. Powered either by an external mains
tended noise monitoring. The enclosure is supply or a small, high-capacity battery
IP66 rated, highly secure and constructed pack, the case is more than adequate for
of strong, hard-wearing reinforced fiber- a number of days of monitoring. The ro-
glass. bust and lightweight design protects the
NTi Audio #: 600 000 480 XL2 and accessories from a wide range
of inclement weather conditions.
Shroud MXA01 NTi Audio #:
The Shroud reduces the acoustic reflec- • IP43 rating: 600 000 471
tions from the XL2 housing back to the • IP63 rating: 600 000 473
microphone capsule for precision class
1 measurements. It supports the XL2 in Heavy-duty Outdoor Case
combination with the 1/2” measurement The heavy-duty outdoor case is a profes-
microphones M2230, M2340, M2211 and sional solution for short- and medium-
M2215. The Shroud is included within the term unattended noise monitoring. The
Type Approval Option. case provides comprehensive protection
NTi Audio #: 600 040 110 against dust, water and impacts. Internal
dimensions provide ample space for bat-
tery packs to power the XL2 Sound Level
Meter.
NTi Audio #:
• IP43 rating: 600 000 476
• IP65 rating: 600 000 477

267
 Further Information

GPS Receiver (customized) Sound Insulation Reporter Software

The specially adapted GNSS receiver Sound Insulation Reporter is a PC-based
comes with a built-in active antenna in software application that provides all the
a white housing. It connects to the XL2 standard reports for Airborne and Impact
Sound Level Meter and the NetBox. Typi- sound insulation measurements. The
cal applications are to synchronize the Sound Insulation Option enables the im-
start time of one or multiple XL2s pre- port of measurement data into the Sound
cisely with the GPS signal (+/- 0.7 ms) or Insulation Reporter software. Download
presenting the precise instrument posi- the software at https://my.nti-audio.com.
tion in NoiseScout Gateway mode for un-
attended noise and vibration monitoring. Room Acoustics Reporter Software
The GNSS receiver supports Galileo, GPS The Room Acoustics Reporter is a PC soft-
and other systems. ware for automatically generating rever-
NTi Audio #: 600 000 357 beration time measurement reports and
analyzing the RTA frequency response
Data Explorer Software spectrum. The Room Acoustics Option
Data Explorer is a PC-based software ap- enables the import of measurement data
plication with a powerful data processor into the Room Acoustics Reporter soft-
for easy and fast analysis of sound level ware. Download the software at https://
measurement data. The data import re- my.nti-audio.com.
quires that the Data Explorer Option be
installed on the XL2. Download the soft-
ware at https://my.nti-audio.com.

268
 Further Information

Sound Power Reporter Software WP30-90/WP61

Sound Power Reporter is a PC-based Windscreen Replacement
software application that provides all the The replacement package contains two
standard reports for sound power mea- spare windscreens for outdoor measure-
surements. The Sound Power Option ment microphones. The outdoor wind-
enables the import of measurement data screen is recommended to be replaced
into the Sound Power Reporter software. annually.
Download the software at https://my.nti- NTi Audio #: 600 040 061
audio.com.
WP30-150 Windscreen Replacement
XL2 Projector PRO Software The replacement package contains two
The Projector PRO software displays the spare windscreens for outdoor measure-
89.4 dBA XL2 screen in real-time on your PC when ment microphones. The outdoor wind-
85.3 dBLeq connected by USB. The Projector PRO op- screen is recommended to be replaced
tion enables the “XL View” and “Sound annually.
Level Predictor” for live sound monitor- NTi Audio #: 600 040 095
ing. Free download from the XL2 Support
Page at https://my.nti-audio.com. 8 GB SD Card (default)
1x included with XL2
1/2” Windscreen 90 mm NTi Audio #: 600 000 374
for M2230, M2340, M2211 and M2215
measurement microphone
NTi Audio #: 600 040 109

269
 Further Information

SD Card 32 GB Lightweight Tripod

Every 32 GB SD Card is individually test- Retractable, lightweight tripod with 1/4”
ed. ball head and 3/8” mounting thread. The
flexible ball head mounts the XL2 Ana-
The XL2 requires an SD card that can con- lyzer at any angle. The tripod is suitable
tinuously and simultaneously store many for all measurement microphones, out-
data streams. Unfortunately, many cards door measurement microphones and the
available on the market are known to in- TalkBox.
terrupt the read/write process for periods NTi Audio #: 600 000 397
of more than 10 seconds. This leads to
data loss in the XL2. These interruptions Minirator MR-PRO
can occur regardless of the speed rating The MR-PRO is an extremely powerful
of the card. Even cards of the same type analog audio generator designed for the
and from the same vendor behave differ- professional engineer. It generates the
ently depending on the production date. following analog audio signals:
Therefore, to ensure the integrity of the • Sine Waveforms, freely selectable fre-
XL2 data recording, NTi Audio verifies ev- quencies and levels up to +18 dBu
ery single card over a period of several • Sweep Signals, any frequency interval
days before the card is sent to our cus- up to 1/12 octave
tomer. Requires XL2 Firmware V4.10 or • White Noise, Pink Noise
higher. • Polarity Test Signal
• Delay Test Signal
Requires XL2 Firmware V4.10 or higher. • Uploaded wav-files (*.wav)
NTi Audio #: 600 000 310
NTi Audio #: 600 000 386

270
 Further Information

NTi Audio TalkBox Warranty Conditions

The NTi Audio TalkBox greatly simplifies
the acoustic feed of the STIPA intelligibil- International warranty
ity test source signal into closed sound NTi Audio guarantees the function of its products and the in-
reinforcement systems. It presents the dividual components for a period of one year from the date
standardized voice-like acoustic signal of sale. During this period, defective products will either be
emission simulating a human talker in ac- repaired free of charge or replaced.
cordance with IEC 60268-16, combined
with a certified speech intelligibility signal Limitations
at standardized levels. These guarantee provisions do not cover damage caused by ac-
NTi Audio #: 600 000 085 cidents, transportation, incorrect use, carelessness, non-origi-
nal accessories, the loss of parts, operation with non-specified
Tracer Battery Adapter Cable input voltages, adapter types or incorrectly inserted batteries.
The Tracer Battery Adapter Cable con- NTi Audio accepts no responsibility for subsequent damage of
nects the Tracer battery pack to a NetBox any kind. The warranty will be voided by carrying out repairs
or an XL2 Analyzer. It ensures that the or services by third parties who are not part of an approved
connected instruments start up properly NTi Audio Service Centre.
if the battery has been completely dis-
charged. Statutory Rights
NTi Audio #: 600 000 478 Consumers may have legal (statutory) rights under applicable
national laws relating to the sale of consumer products. This
warranty does not affect your statutory rights. You may assert
any legal rights you have at your sole discretion.

271
 Further Information

Service and Repairs Calibration Certificate

If your product is not functioning correctly or is damaged, Your NTi Audio instrument has been tested during manufacture
please contact the local NTi Audio partner for assistance. If and conforms to the specifications listed in “Technical Data”.
the product needs to be returned for service, kindly follow the
service guidelines at www.nti-audio.com/service. The XL2 combination with the appropriate measurement mi-
crophone forms a precise class 1 or class 2 sound level meter
in accordance with the standards and configurations listed in
“Technical Data”.

Damage through shocks and moisture You may order a manufacturer calibration certificate of your
• The protective shock jacket shields the instru- new instrument at the local NTi Audio partner either with or
ment against reasonable impacts that could any time after the purchase of the instrument. The certificate
occur in normal use. lists the individual instrument data with serial number recorded
• Do not intentionally subject the instrument to prior to the shipment.
extreme stress!
• Please do not drop the instrument! NTi Audio recommends annual calibration of the products start-
• Damage caused by dropping or impact is not ing one year after the purchase. The calibration provides docu-
covered by warranty. mented and traceable measurement accuracy and confirms
• Do not use the instrument in damp environ- that your NTi Audio product meets or exceeds the published
ments! The instrument can be permanently specifications. The calibration and adjustment procedures fol-
damaged if exposed to moisture. low the documentation and traceability requirements of the
EN ISO / IEC 17025 standard.

For calibrations kindly follow the service guidelines at

www.nti-audio.com/service.

272
 Further Information

Sample Calibration Certificate

Calibration of: XL2 Audio and Acoustic Analyzer
Serial Number: A2A-11667-E0
Date: 25 July 2016

• Measurement Data on Receipt: in tolerance

• Detailed Calibration Test Results:

actual XL2 calibration
reference before actual unit error tolerance uncertainty2
RMS Level @ 1kHz, XLR Input 0.1 0.100 0.100 V ≤0.1% ±0.5% ±0.10%
1 0.999 1.000 V ≤0.1% ±0.5% ±0.09%
10 9.987 9.989 V -0.1% ±0.5% ±0.09%
Manufacturer Calibration Certificate
Flatness, XLR Input1 20 Hz 1 0.997 0.996 V -0.4% ±1.1% ±0.09%
20 kHz 1 1.004 1.004 V 0.4% ±1.1% ±0.09%

The following instrument has been tested and calibrated to the manufacturer specifications. Frequency 1000 1000.00 999.99 Hz ≤0.003% ±0.003% ±0.01%

Sa
The calibration is traceable in accordance with ISO/IEC 17025 covering all instrument functions.
Residual Noise XLR < 2 uV < 2 uV <2 uV ±0.50%

• Device Type: XL2 Audio and Acoustic Analyzer THD+N @ 0 dBu, 1 kHz, XLR Input -98.5 -98.9 dB typ. -100 dB ±0.50%
Sa

• Serial Number: A2A-11667-E0

m
• Test Conditions: Temperature: 28.2 °C
Relative Humidity: 51.7 %

pl
m

• Calibration Equipment Used:

e
pl

- Agilent Multimeter, Typ 34401A, Serial No. MY 5300 4607

Last calibration: 17.08.2016, Next calibration: 17.08.2017
• Date of Calibration: 25 July 2016 Calibrated by ELCAL to the national standards maintained
at Swiss Federal Office of Metrology. SCS 002
e

• Certificate Number: 42576-A2A-11667-E0

- FX100 Audio Analyzer, Serial No. 10408
Last Calibration: 04.05.2016, Next Calibration: 04.05.2017
• Results: PASSED Manufacturer calibration based on Agilent 34410, Serial No. MY47014254,
(for detailed report see next page) Last Calibration: 03.06.2016, Next Calibration: 03.06.2017
which is calibrated by ELCAL to national standards maintained
at Swiss Federal Office of Metrology. SCS 002

Tested by: M. Frick 1

The specified tolerance +/-0.1 dB @ 1V = +/- 1.1%

Signature: 2 The reported expanded uncertainty is based on a standard uncertainty multiplied by a coverage factor k=2, providing a
level of confidence of approximately 95%. The uncertainty evaluation has been carried out in accordance with the
regulations of the GUM.
Stamp:
NTi Audio AG • Im alten Riet 102 • 9494 Schaan • Liechtenstein • Europe • Tel: +423 239 6060
www.nti-audio.com • HR-Nr: 2.012.557 • MwStNr: 54306 • Bank: VP Bank, Vaduz, Acc No: 322.235.015 2/2

NTi Audio AG • Im alten Riet 102 • 9494 Schaan • Liechtenstein • Europe • Tel: +423 239 6060
www.nti-audio.com • HR-Nr: 2.012.557 • MwStNr: 54306 • Bank: VP Bank, Vaduz, Acc No: 322.235.015 1/2

273
 Further Information

Declaration of Conformity Information for Disposal and Recycling

CE / FCC Compliance Statement

We, the manufacturer NTi Audio AG, Im alten Riet 102, 9494 Dispose of the instrument in accordance with
Schaan, Liechtenstein, do hereby declare that the XL2 Ana- the legal environmental regulations in the
lyzer, the measurement microphones M2230, M2340, M2211, country.
M2215, M2914, M4261, the preamplifiers MA220, MA230
and accessories, comply with the following standards or other
standard documents:
• EMC: 2014/30/EU Regulations for the EU and other European countries
• Harmonized standards: EN 61326-1 with corresponding laws
• Explosive atmospheres (ATEX): 2014/34/EU The instrument must not be disposed of in the household gar-
• Directive 2011/65/EC on the restriction of the use of certain bage. At the end of its service life, bring the instrument to a
hazardous substances in electrical and electronic equipment collecting point for electrical recycling in accordance with the
(RoHS). local legal regulations.
• Directive 2012/19/EU on waste electrical and electronic
equipment (WEEE).
Other countries outside the EU
This declaration will become invalid if modifications to the Contact the respective authorities for the valid environmental
instrument are carried out without the written approval of regulations in the country.
NTi Audio.

Date: 07. July 2023

Position: CEO
274
Further Information

275
 Specifications

23. Technical Data XL2 Product Con-

figurations
• XL2 with M4261 microphone
Class 2 in accordance with IEC 61672 and
Class 2 ANSI S1.4
All specifications are according to the IEC61672 standard. Conforms • IEC 61672:2013, IEC 61672:2003,
Other standards are listed the corresponding specifications. with Stan- IEC 61260:2014, IEC 61260:2003,
dards IEC 60651, IEC 60804, IEC 61183
• SMPTE ST 202:2010, ISO 2969:2015
Sound Level Meter
• China: GB/T 3785:2010, GB/T 3241, GB 3096-2008,
Certified • XL2 with TA-Option, M2230 Microphone and GB 50526, GB-T 4959
Product Con- Shroud MXA01 form an integrating sound level • Germany:
figurations meter with type approval in accordance with » DIN 15905-5, DIN 45657:2014, DIN 45657:2005,
Class 1 class 1 requirements of IEC 61672 and ANSI S1.4 DIN 45645-2
» DIN 45645-1
Product Con- The XL2 is identical to the certified configuration, (optional with Extended Acoustic Pack)
figurations just using the latest firmware. • Japan: JIS C1509-1:2005, JIS C 1513 class 1,
Class 1 JIS C 1514 class 0
• XL2 with M2230 or M2340 microphone • Switzerland: V-NISSG
Class 1 in accordance with IEC 61672 and • UK: BS 4142:2014, BS 5969, BS 6698
ANSI S1.4 • US: ANSI S1.4:2014, ANSI S1.43, ANSI S1.11:2014,
ANSI/ASA S12.60
• XL2 with M2211 or M2215 microphone • International IEC standards are adopted as European
Class 1 frequency response in accordance with standards and the letters IEC are replaced by EN.
IEC 61672 and ANSI S1.4 XL2 conforms to these EN standards.
• WELL Buildings, LEED Green Building
These specifications apply for operation with the • FGI Facility Guidelines Institute
microphone attached using the Shroud MXA01 or Weighting • Frequency weighting: A, C, Z (simultaneous)
the microphone detached using the ASD cable. This • Time weighting: (simultaneous)
prevents possible acoustic reflections from the XL2 » Fast, Slow
housing and ensures a high measurement accuracy » Impulse (optional with Extended Acoustic Pack)
in accordance with the standards IEC 61672 and
Level Details • Measurement bandwidth (-3dB): 4.4 Hz - 23.0 kHz
ANSI S1.4.
• Level resolution: 0.1 dB
• Internal noise: 1.3 µV A-Weighted

276
 Specifications

Audio • Default Stabilization < 10 seconds

Recording » Recording of compressed wav-files Time
(ADPCM - 4 bit, 24 kHz)
Integration • Minimum: 1 second
» a new wav-file starts every 12 hours
Time • Maximum: 100 hours minus 1 second
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 10.2 kHz Display Three level ranges depending on the microphone
• Optional: Extended Acoustic Pack Measure- sensitivity with manual setting. For example:
» Recording of linear wav-files (24 bit, 48 kHz) ment • M2230, M2340 @ sensitivity = 42 mV/Pa
» a new wav-file starts every 1 hours Ranges » LOW, lower level range: 0 - 100 dBSPL
(max. wav-file size 512 MB) » MID, mid-level range: 20 - 120 dBSPL
» Bandwidth: 2.0 Hz - 23.6 kHz » HIGH, upper level range: 40 - 140 dBSPL
• Optional: NoiseScout - Managed Mode • M2215 @ sensitivity = 8 mV/Pa
» Recording of compressed wav-files » LOW, lower level range: 20 - 120 dBSPL
(4 bit, 12 kHz) » MID, mid-level range: 40 - 140 dBSPL
» Bandwidth: 2.0 Hz - 5.1 kHz » HIGH, upper level range: 60 - 160 dBSPL
» requires activated “NoiseScout 365” or • M2211 @ sensitivity = 20 mV/Pa
“Data Day Credits” » LOW, lower level range: 10 - 110 dBSPL
• Audio files include meta data (scaling, time, ...) in » MID, mid-level range: 30 - 130 dBSPL
Broadcast Wave Format BWF according to EBU » HIGH, upper level range: 50 - 150 dBSPL
TECH 3285 • M4261 @ sensitivity = 16 mV/Pa
» LOW, lower level range: 10 - 110 dBSPL
Measure- • XL2+M2230: 17 dB(A) - 137 dB
» MID, mid-level range: 30 - 130 dBSPL
ment • XL2+M2340: 18 dB(A) - 138 dB
» HIGH, upper level range: 50 - 150 dBSPL
Ranges with • XL2+M2215: 25 dB(A) - 153 dB
different • XL2+M2211: 21 dB(A) - 144 dB
microphones • XL2+M4261: 27 dB(A) - 146 dB
@ typical microphone sensitivity
Linear Mea- • XL2+M2230: 24 dB(A) - 137 dB, 27 dB(C) - 137 dB
surement • XL2+M2340: 25 dB(A) - 138 dB, 28 dB(C) - 138 dB
Range acc. • XL2+M2215: 33 dB(A) - 153 dB
IEC61672 / • XL2+M2211: 29 dB(A) - 144 dB
ANSI S1.4 • XL2+M4261: 33 dB(A) - 146 dB
@ typical microphone sensitivity

277
 Specifications

Residual • Frequency weighting A Measure- • SPL actual, Lmin, Lmax, Lpeak, Leq, Lp
noise in [dB] ments • Gliding LAeq and LCeq with selectable time win-
Level range Leq Lpeak
@S= dow from one second to one hour
42 mV/Pa LOW 4 17 (=running Lxeq or sliding Lxeq with x= A or C)
of XL2 MID 18 31 • All measurement results simultaneously available
without • Correction value measurement wizard based on
measure- HIGH 43 55 LAeq, LCeq and LCpeak
ment • Noise exposure level LEX with post-processing
microphone • Frequency weighting C • Logging all data or subsets in selectable intervals
Level range Leq Lpeak • Recording of voice notes
• Monitoring of sound levels that exceed limits
LOW 3 16 • Digital I/O interface for external peripherals control
MID 17 30 Real-Time • Conforms with class 1 of IEC 61260:2014 and
HIGH 41 55 Analyzer ANSI S1.11-2014
RTA • 1/1 octave band display: 8 Hz - 16 kHz
• Frequency weighting Z sub ranges 8 Hz - 4 kHz or 31.5 Hz - 16 kHz
• 1/3 octave band display: 6.3 Hz - 20 kHz
Level range Leq Lpeak
sub ranges 6.3 Hz - 8 kHz or 20 Hz - 20 kHz
LOW 7 20 • Level resolution: 0.1 dB
• Measurement Units: Volt, dBu, dBV and dBSPL
MID 21 34
• Band pass filters (base 10) conform with class 1 of
HIGH 46 58 IEC 61260:2014 and ANSI S1.11-2014
» 1/1 octave spectrum: > 16 Hz band
» 1/3 octave spectrum: > 16 Hz band
• Broadband A/Z levels simultaneously
• Frequency weighting: X-Curve @ 500 seats in ac-
cordance with SMPTE ST 202:2010 and
ISO 2969:2015 (not available for XL2-TA)
• Capturing of a single reading into the internal
memory for comparative measurements
• Leq logging

278
 Specifications

Remote • Querying measurement data online via the USB Functions of • SLMeter/RTA function
Measure- interface of the following functions: Extended » Recording of linear wav-files (24 bit, 48 kHz)
ment » Sound level meter and spectrum analyzer Acoustic a new wav-file starts every 1 hour (max. wav-file
(optional) SLMeter/RTA Pack size 512 MB)
» FFT analyzer (optional) » Percentiles for wide band, 1/1 and 1/3 octave
» RT60 reverberation time spectrum
» Audio analyzer RMS/THD+N - Flexible setting from 0.1% to 99.9%
» High-resolution spectral analyzer 1/12 Oct + Tol - Sampling: every 1.3 ms
• Typical response time: 10 ms - Wide band: in 0.1 dB wide classes, based on
@ querying the frequency spectrum in SLMeter sampling Lxy (x= A, C or Z, y= F, S or EQ1”)
- 1/1 and 1/3 octave spectrum: in 1.0 dB wide
classes, based on Lxy (x= A, C or Z, y= F or S)
- Dynamic range: 140 dB
» Sound Exposure Level LAE
» 100ms logging
» RTA logging of Lmin and Lmax
» Event-triggered audio and data recording
» Time weighting: Impulse
(LxI, LxIeq with x= A, C, Z)
» True peak level in 1/1 and 1/3 octave resolution
» Clock-Impulse Maximum Level (TaktMax) in ac-
cordance with DIN 45645-1 and DIN 45657
» Impulsiveness detection in accordance with
BS4142:2014 and NordTest ACOU 112
• FFT function
» High-resolution Zoom-FFT with selectable fre-
quency ranges and resolution up to 0.4 Hz in the
range of 5 Hz to 20 kHz
» Recording of linear wav-files (24 bit, 48 kHz)
• RT60 function
» Reverberation time in 1/3 octave resolution
• 1/12 octave Spectral Analyzer
(requires Spectral Limits Option)
» Recording of linear wav-files (24 bit, 48 kHz)
279
 Specifications

Functions of • SLMeter/RTA function Reporting and Analysis Software

Spectral » True peak level in 1/1 and 1/3 octave resolution
Data • Enables the import of measurement data into the
Limits • FFT function
Explorer Data Explorer software
Option » High-resolution Zoom-FFT with selectable fre-
(optional) • Powerful data processor for easy and fast analysis
(optional) quency ranges and resolution up to 0.4 Hz
of sound level measurement data on PC
» Sound mode: 5 Hz to 20 kHz
» Vibration mode: 1 Hz to 20 kHz Sound • Enables the import of RTA and reverberation time
• 1/12 octave function Insulation measurement data in 1/3 octave band resolution
» High-resolution RTA function “1/12 Oct + Tol” Reporter into the XL2 Sound Insulation Reporter software
» Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral (optional) • Software provides all tools for fast data analysis
resolution and standardized reporting of airborne, impact and
» Frequency band listening at rear speaker facade sound insulation measurements on PC
» Sound Mode: 11.5 Hz to 21.8 kHz • Standards ASTM E336, ASTM E413, ASTM E1007,
» Vibration mode: 0.73 Hz to 1.36 kHz ASTM E989, ASTM E966, ASTM E1332, BB93,
• FFT and 1/12 octave function DIN 4109, Document E, GB/T 19889, ISO 16283,
» Capturing of multiple readings into the internal ISO 140, ISO 717, ISO 10140, NEN 5077:2019, SIA
memory 181:2006, SIA 181:2020
» Comparing measurement results against cap- Room • Frequency response spectrum and Noise Curves
tures with relative or absolute curve display Acoustics • Room acoustic simulation according to Sabine or
» Comprehensive tolerance handling with toler- Reporter Eyring
ance masks based on captures for passed/failed (optional) • Import of own sound absorber database and toler-
measurements ances
» Export and import of tolerance and capture files • Standards GB 50371, IEC 61260, ANSI/ASA S12.2-
• Noise Curves 2019, DIN 15996:2020, ISO R 1996-1971, ASR
» Noise Rating NR according to ISO/R 1996-1971 A3.7:2021, DIN 18041:2016, ISO 3382-1:2009,
» Noise Criteria NC ISO 3382-2:2008, ÖNORM B 8115-3:2015, ASTM
in accordance with ANSI S12.2-2019 and -1995 C423-17, ISO 354:2003
» Room Noise Criteria RNC
in accordance with ANSI S12.2-2019
» Room Criteria RC
in accordance with ANSI S12.2-1995
» Preferred Noise Criteria
in accordance with ASA 1971

280
 Specifications

Sound • Enables the import of RTA and reverberation time Acoustic Analyzer
Power measurement data in 1/1 and 1/3 octave band res-
FFT Analysis • Real-time FFT with actual level, Leq, Lmin, Lmax
Reporter olution into the Sound Power Reporter software
• Level resolution: 0.1 dB
(optional) • Software provides all the standard reports for
• Frequency Band Ranges: 7 Hz - 215 Hz,
sound power measurements
58 Hz - 1.72 kHz, 484 Hz - 20.5 kHz with 143 fre-
• Standards ISO 3741, ISO 3744, ISO 3746, ANSI-
quency bins shown on display
ASA S12.51, S12.54, S12.56
• Measurement Units: Volt, dBu, dBV and dBSPL
• Optional with Extended Acoustic Pack or Spectral
Limits: High-resolution Zoom-FFT with selectable
frequency ranges and resolution up to 0.4 Hz in
the range of 5 Hz to 20 kHz
• Optional with Spectral Limits:
Capture and tolerance function with multiple read-
ings for comparative measurements and passed/
failed analysis
Reverbera- • Conforms with ISO 3382 and ASTM E2235
tion • 1/1 octave bands results from 63 Hz - 8 kHz,
Time RT60 based on T20 and T30
• Optional with Extended Acoustic Pack:
1/3 octave bands results from 50 Hz - 10 kHz
based on T20 and T30
• Range: 10 ms - 30 seconds
• Minimum reverberation time (typical)
» < 100 Hz: 0.3 second
» 100 - 200 Hz: 0.2 second
» > 200 Hz: 0.1 second
• Measurement based Schroeder-method
• Test signal: Impulse source or interrupted pink
noise generated by the MR-PRO, MR2 or the in-
cluded NTi Audio Test CD / USB Flash Drive

281
 Specifications

Polarity • Checks polarity of speakers and line signals 1/12 Octave • Actual level, Lmin, Lmax, Leq, Leq1”, Leq4”
• Positive/Negative detection of wideband and Analysis • Selectable 1/1, 1/3, 1/6 and 1/12 octave spectral
individual 1/1 octave bands through internal micro- (optional) resolution
phone or XLR/RCA connector • Measurement Units: Volt, dBu, dBV and dBSPL
• Test signal: NTi Audio polarity test signal gener- • Band pass filters (base 10)
ated by the MR-PRO, MR2 or the included NTi • Capturing of multiple readings into the internal
Audio Test CD / USB Flash Drive memory
• Comparing measurement results against captures
Delay Time • Propagation delay between electrical reference
with relative or absolute curve display
signal and acoustic signal using the internal micro-
• Comprehensive tolerance handling
phone
• Creating tolerance masks based on captures for
• Range: 0 ms - 1 second (0 m - 344 m)
passed/failed measurements
• Resolution: 0.1 ms
• Test signal: NTi Audio delay test signal generated Cinema • Measurements in 1/3 octave resolution in accor-
by the MR-PRO, MR2 or the included NTi Audio Meter dance with SMPTE ST 202:2010 and SMPTE RP
Test CD / USB Flash Drive (optional) 200:2012
• An interactive assistant guides the user through
Noise • Noise Rating NR according to ISO/R 1996-1971
dedicated measurement procedures.
Curves • Noise Criteria NC
• Consists of
in accordance with ANSI S12.2-2019 and -1995
» Spectral Limits Option
• Room Noise Criteria RNC
NTi Audio # 600 000 376
in accordance with ANSI S12.2-2019
» Cinema Assistant Option
• Room Criteria RC
NTi Audio # 600 000 378
in accordance with ANSI S12.2-1995
• Preferred Noise Criteria
in accordance with ASA 1971

• Application range of measurement microphones:

» M2230: down to NC15
» M2340: down to NC15
» M2211: down to NC20
» M4261: down to NC25

282
 Specifications

STIPA • Measurement in accordance with the standards Audio Analyzer

Speech » IEC 60268-16 (edition 2, 3, 4 or 5)
Conforms • IEC 61672, IEC 60651, IEC 60804
Intelligibility » AS 1670.4
with Stan- • DIN EN 60065, VDE 0860, IEC 468-4
(optional) » BS 5839-8
dards
» CEN/TS 54-32:2015
» DIN EN 50849:2017 Level RMS • True RMS detection in V, dBu, dBV, dBSPL
» ISO 7240-16 (dBSPL not available for XL2-TA)
» ISO 7240-19:2007 • Power measurement in Watt W or dBm
» DIN VDE 0833-4 with flexible load setting from 1.0 to 9999 Ohm
» VDE V 0833-4-32:2016 • Range XLR/RCA input: 2 µV - 25 V (-112 dBu to
» VDE 0828-1:2017-11 +30 dBu)
» NFPA 72 • Accuracy: ± 0.5 % @ 1 kHz,
» UFC 4-021-01 • Flatness: ± 0.1 dB @ 12 Hz to 21.3 kHz
• Direct measurement method (IEC 60268-16) • Bandwidth (-3 dB): 5 Hz to 23.6 kHz
• Frequency range: 125 Hz - 8 kHz in octave band • Resolution: 3 digits (dB scale),5 digits (linear scale)
• Modulation frequencies 0.63 Hz - 12.5 Hz in third- or 6 digits (x1 scale)
octave resolution Real-Time Following measurement functions offer audio spec-
• Single value STI and CIS test result Analyzer trum in Volt, dBu and dBV
• Ambient noise correction RTA • Sound Level Meter
• Automated averaging of measurements • FFT
• Modulation indices and individual band level re- • 1/12 Octave (optional with Spectral Limits)
sults with error indicator
• Test signal: NTi Audio STIPA signal generated by Frequency • Range: 9 Hz to 21.3 kHz
the MR-PRO, NTi Audio TalkBox or other audio • Resolution: 6 digits
players (download wav-file at https://my.nti-audio. • Accuracy: < ± 0.003%
com/support/xl2) THD+N • Range: -100 dB to 0 dB (0.001% to 100%)
(Total Har- • Minimum level: > -90 dBu
monic • Fundamental frequency range: 10 Hz to 21.3 kHz
Distortion + • Measurement bandwidth: 2 Hz to 23.6 kHz
Noise) • Resolution: 3 digits (dB scale) or 4 digits (linear
scale)
• Residual THD+N @ XLR/RCA input: < 2 µV
Scope Auto ranging, auto scaling

283
 Specifications

Filter • Frequency weighting: A, C, Z Vibration Meter

• Highpass 100Hz, 400 Hz, 19 kHz,
Channels • 1 (Single-channel)
• Bandpass 22.4 Hz - 22.4 kHz in accordance with
IEC468-4 Parameters • Real time measurement in
» Acceleration: m/s2, g, in/s2, dB
Remote Querying measurement data online via the USB
» Velocity: m/s, in/s, dB
Measure- interface of the following functions:
» Displacement: m, in, dB
ment • Sound level meter and spectrum analyzer
» Peak particle velocity PPV: mm/s, in/s
(optional) SLMeter/RTA
» Levels: RMS, Peak, Peak-Peak
• FFT analyzer
• RT60 reverberation time VibMeter • Broadband level
• Audio analyzer RMS/THD+N » Frequency range: 0.8 Hz - 2.5 kHz
• High-resolution spectral analyzer 1/12 Oct + Tol • Spectral
» 1/1 octave band display: 1 Hz - 2.0 kHz
sub ranges 1 Hz - 500 Hz or 4 Hz - 2 kHz
Calibration » 1/3 octave band display: 0.8 Hz - 2.5 kHz
sub ranges 0.8 Hz - 1.0 kHz, 2.5 Hz - 2.5 kHz
Free-field • NTi Audio Class 1 Sound Calibrator
» Broadband level measured with
Correction » M2230: -0.1 dB
bandwidth (- 3dB): 0.7 Hz – 23.6 kHz
» M2340: -0.1 dB
• Display according to DIN 45669-1:2010
» M2211: -0.1 dB
» Unweighted velocity v(t)
» M2215: -0.1 dB
» Maximum absolute velocity ¦v¦max
• NTi Audio Class 1 Sound Calibrator with
» Averaging duration Tm
1/4” Calibration Adapter, type ADP 1/4-P
» Measurement duration TM
» M4260: +0.1 dB
» M4261: +0.2 dB Filter • Flat (no filter)
Bandwidth (- 3dB): 0.7 Hz – 23.6 kHz
Wind Screen • 50 mm Wind Screen: +0,12 dB
• 10 - 1000 Hz according to ISO 2954 with decay
Correction • 90 mm Wind Screen: +0,19 dB
rate = 18 dB / octave
• WP30/WP61 Wind Screen 90 mm: +0,19 dB
• 1 - 80 Hz, 1 - 315 Hz acc. to DIN 45669-1:2010
Calibration • Recommended calibration interval: one year with decay rate = 12 dB / octave
• Microphone calibration with external calibrator
supported
• Optional calibration certificate for new instru-
ments available

284
 Specifications

Audio • Default Reference- • Mid

Recording in » Recording of compressed wav-files measurement
VibMeter (ADPCM - 4 bit, 24 kHz) range
» a new wav-file starts every 12 hours
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 10.2 kHz
• Optional: Extended Acoustic Pack
» Recording of linear wav-files (24 bit, 48 kHz)
» a new wav-file starts every 1 hours
(max. wav-file size 512 MB)
» Bandwidth: 2.0 Hz - 23.6 kHz
FFT Analysis • Frequency range: 1 Hz - 1.69 kHz
• Optional with Extended Acoustic Pack or Spec-
tral Limits: High-resolution Zoom-FFT with se-
lectable frequency ranges and resolution up to
0.4 Hz in the range of 1 Hz to 20 kHz
1/12 Octave • Actual level, Lmin, Lmax, Leq, Leq1”, Leq4”
Analysis • Selectable 1/1, 1/3, 1/6 and 1/12 octave spec-
(optional) tral resolution
• Measurement Units
» Acceleration: m/s2, g, in/s2, dB
» Velocity: m/s, in/s, dB
» Displacement: m, in, dB
• Band pass filters (base 10)
• Frequency range: 0.73 Hz - 1.36 kHz
Maximum Input • 353 m/s2, 36 g @ 20 mV/(m/s2)
Level with ICP Adapter ASD
Residual Noise • 17 µV @ 0.7 Hz ... 23.0 kHz
(typical) with • 14 µV @ 1 Hz ... 315 Hz
ICP Adapter • 14 µV @ 1 Hz ... 80 Hz
ASD

285
 Specifications

Input / Output Interfaces Memory SD Card included (8 GByte), removable, storing

measurement data in ASCII format, screen shots,
Audio Inputs • XLR balanced
voice notes and wav-files
» Input impedance = 200 kOhm
» Phantom power: +48 VDC switchable with maxi-
Data logging every second offers following noise
mum 10 mA supply current in accordance with
monitoring periods:
IEC 61938
• Logging default noise levels: > 2 years
» Automated sensor detection for NTi Audio’s ASD
• Additional logging of 1/3 octave data: > 6 month
measurement microphones and pre-amplifiers
• Additional
• RCA unbalanced with input impedance >30 kOhm
» compressed audio recording: > 1 week
• Built-in condenser microphone for polarity testing,
» linear audio recording: > 15 hours
delay measurements and voice note recording
Audio • Built-in speaker Optional 32 GB SD Cards are available for longer
Outputs • Headphone connector monitoring requirements; requires XL2 Firmware
» 3.5 mm Minijack V4.10 or higher.
» mono monitor wired to both channels of stereo
Power • Rechargeable Li-Po battery included
jack
Supply » Type 3.7 V / 2260 mAh
» Linear output signal over a measurement range
» Typical battery lifetime > 4 hours
of 57 dB in SLMeter measurement function
» Range: 3.3 - 4.5 VDC
» Maximum output level: 0.33 Vrms / 0.47 Vp
» Volume energy density = 339 Wh/l
USB Inter- USB mini connector for data transfer to PC, XL2 • Dry cell batteries type AA, 4 x 1.5 V
face Projector PRO and/or charging of Li-Po battery » Typical battery lifetime > 4 hours
Digital I/O Connection interface to accessories » Range: 3.7 - 6.0 VDC
• XL2 Input Keypad • Linear external power supply 9 VDC
• Limit Light » Range: 7.5 - 20.0 VDC @ minimum 6 Watt
• Stack Light » Charges Li-Po battery during operation
• Digital I/O Adapter PCB » Connector C5.5 x 2.1 x 12 mm
• USB-Power Supply
TOSLink 24 bit linear PCM audio signal output » for short-term operation < 1 day
(prepared for later firmware extension) » charging power is equal or less than power con-
sumption

286
 Specifications

Power • External battery pack Electromag- CE compliant:

Supply » 22 Ah battery pack: 4 days netic Com- EN 61326-1 Class B, EN 55011 class B
» 44 Ah battery pack: 8 days patibility EN 61000-4-2 to -6 & -11
Protection IP51
General
Rating
Clock • Default
ATEX • For applications in explosive atmospheres within
» Real-time clock with lithium backup battery
zone 2 in accordance with IEC 60079
» Typical life backup battery: 8 years
• Directive 2014/34/EU
» Return instrument for battery replacement
» Drift < 1.7 seconds per 24 hours
• Special XL2 edition, NTi Audio # 600 000 356
» VCXTO clock
» Drift < 0.04 seconds per 24 hours
Mechanics • Tripod or microphone stand mount 1/4”
• Wire stand mounted on rear side
• Display: 160 x 160 pixels grey scale with LED back
light
• Dimensions (L x W x H)
» 180 mm x 90 mm x 45 mm
» 7.1” x 3.5” x 1.8”
• Weight: 480 g (1 lb) including built-in Li-Po battery
Temperature -10 °C to +50 °C (14° to 122°F)
Humidity 5% to 90% RH, non-condensing
Static air 65 kPa to 108 kPa
pressure
Susceptibil- Classification Group X
ity to radio
frequencies

287
 Specifications

24. Technical Data Microphones

M2230 M2340 M2211 M2215 M4261 M2914
(with self-test) (high levels) Low-Noise
Classification with XL2 according Class 1 Class 1 Frequency Response Class 2 Frequency Re-
to IEC 61672, ANSI S1.4 certified certified Class 1 sponse Class 1
Consisting of PreAmplfier PreAmplfier PreAmplfier PreAmplfier M4261 micro-
MA220 + MA230 + MA220 + MA220 + phone with
MC230 or MC230A Capsule 7052 Capsule 7056 permanently
MC230A Capsule installed
Capsule capsule
Microphone Type Omnidirectional, pre-polarized condenser,
free field microphone
Capsule / Transducer 1/2” detachable, 60UNS2 thread, 1/4” permanent- 1/2” detachable,
type WS2F, IEC 61094-4 ly installed 60UNS2 thread,
type WS2F,
IEC 61094-4
PreAmplifier Type MA220 MA230 MA220 - MA214
System Self-test (CIC) - with XL2 -
Flatness tolerance bands ±1 dB @ 5 Hz - 20 Hz +1/-4.5 dB @ 5 ±2 dB @ 10 Hz –
typical ±1 dB @ >20 Hz - 4 kHz Hz - 20 Hz 16 kHz
±1.5 dB @ >4 kHz - 10 kHz ±1.5 dB @ >20 ±3 dB @ 5 Hz –
±2 dB @ >10 kHz - 16 kHz Hz - 4 kHz 20 kH
±3 dB @ >16 kHz - 20 kHz ±3 dB @ >4 kHz
- 10 kHz
±4.5 dB @ >10
kHz - 16 kHz
±5 dB @ >16
kHz - 20 kHz

288
 Specifications

M2230 M2340 M2211 M2215 M4261 M2914

(with self-test) (high levels) Low-Noise
Actual Frequency Response freely available as Excel-data, register product at https://my.nti-audio.com and
contact info@nti-audio.com
Frequency Range 5 Hz - 20 kHz
Residual Noise Floor typical 16 dB(A) 17dB(A) 21 dB(A) 25 dB(A) 27 dB(A) 6.5 dB(A)
Maximum SPL 137 dBSPL 138 dBSPL 144 dBSPL 153 dBSPL 142 dBSPL Peak 103 dB /
@ THD 3%, 1 kHz, S_typical RMS 100 dB
Sensitivity typical @ 1 kHz -27.5 dBV/Pa -34 dBV/Pa -42 dBV/Pa -36 dBV/Pa 320 mV/Pa
±2 dB ±3 dB ±3 dB ±4 dB
(42 mV/Pa) (20 mV/Pa) (8 mV/Pa) (16 mV/Pa)
Temperature Coefficient < -0.01 dB / °C < ±0.015 dB / °C < ±0.02 dB / °C < ±0.01 dB / °C
Temperature Range -10°C to +50°C 0°C to +40°C –20°C to +60°C
(14°F to 122°F) (32°F to 104°F) (–4°F to 140°F)

Pressure Coefficient -0.005 dB / kPa -0.02 dB / kPa -0.04 dB / kPa –0.00001 dB/Pa
Influence of Humidity < ±0.05 dB < ±0.4 dB < 90% R.H.,
(non-condensing) non-condensing
Humidity 5% to 90% RH, non-condensing
Long-term Stability > 250 years / dB -
Power Supply 48 VDC phantom power ICP
Current Consumption typical 2.3 mA 0.8 mA 2.3 mA 1.7 mA 4 – 20 mA
Electronic Data Sheet NTi Audio ASD in accordance with IEEE P1451.4 V1.0, Class 2, Template 27
Output Impedance 100 Ohm balanced < 100 Ω
Connector Balanced 3-pole XLR BNC
Diameter Dimensions 20.5 mm (0.8”) 12.7 mm (0.5”),
protection grid
13.2 mm (0.52”)

289
 Specifications

M2230 M2340 M2211 M2215 M4261 M2914

(with self-test) (high levels) Low-Noise
Length Dimensions 154 mm (6.1”) 150 mm (5.9”) 135 mm (5.3”)
Weight 100 g (3.53 oz) 83 g (2.93 oz) 250 g (8.8 oz)
Environmental Protection IP51
Windscreen Diameter 50 mm (2”) 90 mm (3.5”) 33 mm (1.3”) 33 mm (1.3”) 33 mm (1.3”) 50 mm (2”)
Scope of Supply Windscreen, Microphone Holder with Adapter 5/8“ - 3/8“, Manual
NTi Audio # 600 040 050 600 040 230 600 040 022 600 040 045 600 040 070 600 040 240

Outdoor Measurement Microphones

M2230-WP M2340-WP M4261-WP
(M2230+WP30) (M2340+WP30) (M4261+WP61)
Classification with XL2 accord- Class 1 Class 1 Class 2
ing to IEC 61672, ANSI S1.4 certified certified
System Self-test (CIC) - with XL2 or XL3 -
Windscreen Diameter 90 mm (3.5”)
Diameter Dimensions 36 mm (1.4”) 36 mm (1.4”) 36 mm (1.4”)
Length Dimensions 378 mm (14.9”) 378 mm (14.9”) 378 mm (14.9”)
Weight 430 g, 15.17 oz 430 g, 15.17 oz 413 g, 14.57 oz
Environmental Protection IP54 in vertical position IP54 in vertical position IP54 in vertical position
Mounting Standard 3/8” tripod mount included
Optional Pole Mount Adapter • Pole Mount Adapter PM 1” for pole diameter 25 - 33 mm (1-1.3”) NTi Audio # 600 040 067
• Pole Mount Adapter PM 1 1/4” for pole diameter 32 - 44 mm (1.25-1.75”) NTi Audio # 600 040 068
NTi Audio # 600 040 050 + 600 040 060 600 040 230 + 600 040 060 600 040 070 + 600 040 080

290
 Specifications

Typical Frequency Response of Measurement Microphones

M2230, M2340,
M4261 M2211, M2215
8
Tolerance
Class 1, IEC61672-1
6

2
Sensitivity relative [dB]

-2

-4 Tolerance
Class 2, IEC61672-1

-6

-8
5 10
10 20 100
100 1000
1000 10000
10000 20000
log frequency [Hz]
(free field conditions @ reference direction 0°)

291
 Specifications

Linear Measurement Range XL2 + M2230: 24 dB(A) - 137 dB XL2 + M2340: 25 dB(A) - 138 dB
acc. IEC61672 / ANSI S1.4
(typ. microphone sensitivity)

XL2 + M2211: 29 dB(A) - 144 dB XL2 + M4261: 33 dB(A) - 146 dB

292
 Specifications

Free Field - Pressure Correction Factors

If a measurement microphone is held in a free-field environ- The following corrections apply with the B&K 4226 calibrator.
ment, then the measurement microphone acts at high fre-
quencies like a reflector. The sound pressure increases in M2230, M2211 M2215 Measurement
front of the microphone capsule membrane. M2230, M2340, M2340 [dB] [dB] Uncertainty U
Nominal
with [dB]
M2211 and M2215 are free-field equalized measurement mi- Frequency
MXR01
[Hz]
crophones, they compensate for the increased pressure inter- Adapter
[dB]
nally. The calibration of the measurement microphones M2230
31.5 -0.3 -0.2 0.0 0.3
and M2340 with the B&K 4226 requires the accessory Adapter
63 0.0 0.0 0.0 0.3
Ring MXR01, NTi Audio # 600 040 105. Please note, never 125 -0.2 -0.1 -0.1 0.3
touch the diaphragm of the measurement microphone capsule. 250 -0.2 -0.1 -0.1 0.3
500 -0.2 -0.1 -0.1 0.3
The calibrator no longer offers free-field conditions. Therefore, 1000 0.0 0.0 0.0 0.3

the free-field equalization of the microphone must be compen- 2000 0.1 0.1 0.0 0.3
4000 0.7 0.7 0.4 0.3
sated. This needs to be considered prior the calibration. The 8000 2.7 4.5 4.7 0.4
correction value needs
​​ to be added to the pressure response
12500 7.2 5.8 6.1 0.7
of the microphone. 16000 7.3 7.9 7.9 0.8

Example:
• During the calibration, the XL2 measures the sound level in Correction values ​​for other calibrators for M2230 and M2340.
the calibrator. If the B&K 4226 calibrator is used and it is set Correction Calibration Calibration
Type
to 16 kHz, then the XL2+M2230 reads just 86.7 dBA. Value Frequency Level

• The free-field sound level is calculated by summing the XL2 NTi Audio CAL200 -0.1 1 kHz 114 dB
measurement value and the correction value (86.7 dB + B&K 4231 -0.2 1 kHz 114 dB
7.3 dB = 94.0 dB). Norsonic Nor-1251 -0.2 1 kHz 114 dB

293
 Specifications

Actuator Correction M2230, M2340

The calibration requires the accessory Actuator Grid, NTi Audio
The following free-field 0° incidence corrections apply for # 600 040 112. The Actuator Grid comes with an insulation ring
calibration using a protection grid actuator (e.g. B&K UA033, dedicated for this measurement method.
GRAS RA0014). Please note, never touch the diaphragm
of the measurement microphone capsule. The maximum Nominal M2230, M2340
DC bias for the actuator calibration is 200 VDC. Frequency [Hz] [dB]
<400 0.0
400 -0.2
500 0.0
M2211, M2215
630 -0.2
Nominal M2211 M2215
800 0.0
Frequency [dB] [dB]
1000 0.0
[Hz]
1250 -0.1
31.5 0.0 0.0
1600 0.2
63 0.0 0.0
2000 0.2
125 0.0 0.0
2500 0.3
250 0.0 0.0
3150 0.8
500 0.1 0.0
4000 1.0
1000 0.1 0.0
5000 1.6
2000 0.6 0.2
6300 2.4
4000 1.7 1.2
8000 3.6
8000 4.2 3.9
10000 4.8
12500 7.3 6.7
12500 6.5
16000 9.2 9.0
16000 9.3
20000 11.7

294
 Specifications

Diffuse-field Sensitivity Level Correction Nominal

Frequency
1/2” Microphone
M2230, M2340,
1/4” Microphone
M4261
M2211, M2215
[Hz]
[dB] [dB]
A diffuse sound field is characterized by the sound arriving at
the receiver from all directions with more or less equal prob- <63 0.0 0.0
63 0.0 0.0
ability. The M2230, M2340, M2211, M2215 and M4261 are 80 0.0 0.0
free-field equalized measurement microphones. The default 100 0.0 0.0
frequency response refers to a 0° sound incidence. The diffuse- 125 0.0 0.0
160 0.0 0.0
field sensitivity level correction is calculated by averaging the
200 0.0 0.0
directional characteristics in accordance with IEC 61183. The
250 0.0 0.0
corrections ​​for diffuse-field conditions are documented in the 315 0.0 0.0
following table and may be activated directly on the XL2; see 400 0.0 0.0
Spectral Corrections. The directional response of the M2230 is 500 0.0 0.0
630 0.0 0.0
described in the appendix.
800 0.0 0.0
1000 0.0 0.0
Example: 1250 0.1 0.1
• The sound pressure level in a diffuse sound field shall be 1600 0.2 0.1
determined. The display of the XL2 with the M2230 reads 2000 0.2 0.1
2500 0.4 0.2
80.0 dBA for the 20 kHz third-octave band.
3150 0.6 0.3
• The diffuse sound level is now calculated from the sum 4000 0.8 0.3
of the XL2 measurement value and the correction value 5000 1.3 0.5
(80.0 dB + 5.9 dB = 85.9 dB). 6300 1.8 0.8
8000 2.5 1.1
10000 3.4 1.6
12500 4.4 2.2
The diffuse-field sensitivity level correction is 16000 5.3 2.8
not necessary using a diffuse field equalized 20000 5.9 3.4
measurement microphone.

295
 Specifications

Free-field and Diffuse-Field Sensitivity for M2230 and M2340

11

00

-1
-1
idealized
free-field
-2
-2
sensitivity relative [dB]

-3
-3

-4
-4

-5
-5 diffuse
field
-6
-6

-7
-7

-8
-8
10
10 20 100
100 1000
1000 10000
10000 20000

log frequency [Hz]

296
 Specifications

Spectral Correction for horizontal Sound Incidents using the Outdoor Microphone
The outdoor measurement microphone fulfills the require- Spectral Correction for horizontal sound incidents:
ments of IEC 61672 and ANSI S1.4 for vertical sound incidence.
For compliance with horizontal sound incidence a spectral cor- Nominal WP30 WP61
rection is employed in the associated XL2 Sound Level Meter. Frequency Weather Protection Weather Protection
[Hz] [dB] [dB]
1/3 Octave 1/1 Octave 1/3 Octave 1/1 Octave

<800 0.0 0.0 0.0 0.0

800 0.0 0.0
1000 0.0 0.0 0.0 0.0
1250 0.1 0.0
1600 0.2 0.2
2000 0.3 0.4 0.3 0.4
2500 0.7 0.8
3150 1.3 1.4
4000 2.0 2.0 2.1 2.0
5000 2.7 2.5
6300 2.9 2.3
8000 3.3 3.4 2.4 2.5
10000 3.9 2.8
12500 4.6 3.0
16000 6.4 5.9 3.1 3.0
20000 6.8 3.1

Select Calibrate Menu: Show Spec Correction in the Sys-

tem Settings. This will enable the spectral correction field in
the Calibration menu.

297
 Specifications

25. Technical Data PreAmplifier

MA220 PreAmplifier MA230 PreAmplifier
with self-test (CIC)
Microphone PreAmplifier Compatible with 1/2” microphone capsules type WS2F in accordance with IEC61094-4
Frequency Range (-3dB) 4 Hz - 100 kHz 1.3 Hz - 50 kHz
Residual Noise Floor typical 1.9 mV(A) at C_in 15 pF ≙ 5.6 dBA @ 42 mV/Pa 2.4 mV(A) at C_in 15 pF ≙ 9.1 dBA @ 42 mV/Pa
Frequency Response Flatness ±0.2 dB ±0.1 dB, 10 Hz - 20 kHz
Phase Linearity < 1° @ 20 Hz - 20 kHz
Maximum Output Voltage 21 Vpp ≙ 7,4 Vrms ≙ 138,9 dBSPL @ 42 mV/Pa 22 Vpp ≙ 7,8 Vrms ≙ 139,3 dBSPL @ 42 mV/Pa
@ THD 3%, 1 kHz
Electronic Data Sheet Containing user calibration data; default factory sensitivity = 4.9 V/Pa
Read/write by XL2 Audio and Acoustic Analyzer
NTi Audio ASD in accordance with IEEE P1451.4 V1.0, Class 2, Template 27
Impedance Input: 20 GOhm // 0.26 pF, Output: 100 Ohm balanced
Power Supply 48 VDC phantom power, 2.3 mA typical 48 VDC phantom power, 0.8 mA typical
Attenuation < 0.17 dB (Rphantom 2x 6.8 kOhm) < 0.07 dB (Rphantom 2x 6.8 kOhm)
Connector Balanced 3-pole XLR
Thread for Capsule 60 UNS2
Weight 90 g, 3.17 oz
Dimensions Length 142.5 mm (5.6”), diameter 20.5 mm (0.8”)
Temperature Range -10°C to +50°C (14°F to 122°F)
Humidity 5% to 90% RH, non-condensing
NTi Audio # 600 040 040 600 040 200

The product specifications may vary based on the mounted microphone capsule type.
298
 Specifications

Appendix
Appendix 1: Standard - Optional Features

Standard Features Optional

Sound Level Meter -

Frequency Weighting

Sound Level Meter • Extended Acoustic Pack:

Time weighting
Impulse

Sound Exposure Level

Percentile Sound Pressure Levels for wide band, 1/1 and

1/3 octave spectrum with flexible setting from 0.1% to
99.9%.

Sound Level Meter -

Correction

299
 Appendix

Standard Features Optional

Sound Level Meter • Extended Acoustic Pack:

Parameter Clock-Impulse Maximum Level (Taktmaximalpegel) in ac-
cordance with DIN 45645-1:

Calculated levels in accordance with DIN 45645-1:

Impulsiveness in accordance with BS4142:2014 and

NordTest ACOU 112

Sound Level Meter supported • Extended Acoustic Pack or Spectral Limits Option:
RTA Spectrum Analyzer
True peak level

300
 Appendix

Standard Features Optional

Sound Level Meter • Recording of wav-files • Extended Acoustic Pack:

Audio Recording (ADPCM compression) Recording of wav-files (24 bit, 48 kHz)
• Voice note recording

Sound Level Meter -

Triggered Event Recording • Extended Acoustic Pack:

Sound Level Meter supported • 100 ms logging

Logging • RTA logging of Lmin and Lmax

FFT Analysis • Extended Acoustic Pack or Spectral Limits Option:

Measurement Range
with zoom function

FFT + Tol - • Spectral Limits:

Capture and Tolerance Capture and Tolerance functionality

RT60 Octave band resolution • Extended Acoustic Pack:

1/3 octave band results

1/12 Oct + Tol - • Spectral Limits:

1/12 Oct + Tol
Capture and Tolerance functionality

301
 Appendix

Standard Features Optional

Noise Curves - • Spectral Limits Option

STIPA - • STIPA Option with STIPA functionality

Cinema Meter - • Cinema Meter Option

Querying measurement - Remote Measurement Option supporting

data online via the USB • Sound level meter and spectrum analyzer SLMeter/RTA
interface • FFT analyzer
• RT60 reverberation time
• Audio analyzer RMS/THD+N
• High-resolution spectral analyzer 1/12 Oct + Tol

302
 Appendix

Appendix 2: Factory Default Profiles

You may start up the XL2 with individual preset application pro-
files.

The profile Full mode is the default configuration with all avail-
able measurement functions enabled.

303
 Appendix

DIN15905-5 / DIN15905-5 & Audio These levels are shown in the numeric result page:
(Sound Level Monitoring in accordance with DIN15905-5) LAeq5”+k1 Time-averaged sound pressure level LAeq
with correction value k1 and a moving time
The following limits apply at all areas accessible by the visitors window of 5 seconds.
during the measurement period of 30 minutes:
LAeq+k1 Time-averaged sound pressure level LAeq
• Maximum averaged level = 99 dB
with correction value k1.
The XL2 displays this maximum level with the measure-
ment result LAeq+k1. LCpeak+k2 C-weighted peak level LCpeak with correc-
• Maximum peak level LCpeak = 135 dB tion value k2.

The following sound levels are displayed in the real-time ana-

lyzer page:
LZFhold3 For tracing of feedback frequencies. The
peak hold time is set to 3 seconds.
LZFlive Actual real-time spectra.

304
 Appendix

How to Measure Limits

• Select the page KSET with the rotary wheel . This profile is configured with the following limits, which trigger
• Measure the correction values k1 and k2 as described in the the lights on the limit button and external Digital I/O Adapter.
chapter Sound Level Meter: Correction Value KSET. This facilitates a quick response to sound levels that exceed
• Press the start button . these limits.
• The icon LOG flashes during the ongoing measurement. In
the case where the profile #DIN15905-5 & Audio has been
selected the icon AUD flashes, indicating the additional au-
dio wav-file logging.
• During the measurement you can monitor the actual sound
level LAeq5”+k1 in order to remain below the permitted lim-
its; alternatively you may monitor the spectrum analyzer for
tracing possible feedback frequencies.
• Press stop to finish the measurement.

In accordance with DIN15905-5, all sound lev-

els are measured, displayed and logged to the
SD Card automatically. The settings are locked,
which ensures that the correct parameters are Measurement Results
measured. You may import the log files into a report generator soft-
The profile #DIN15905-5 & Audio includes the ware based on MS Excel, providing automatically-completed
recording of Compressed+AGC wav-files. live event reports with noise level charts. The report genera-
tor software is a free download on the support website at
https://my.nti-audio.com for all registered XL2 customers.

305
 Appendix

V-NISSG 100dB / V-NISSG 100dB&Audio

(Sound Level Monitoring in accordance with V-NISSG)

The following limits apply at all areas accessible by the visitors

during the moving measurement period window of 60 minutes
during the live event:

• Maximum averaged level

The XL2 displays this maximum level with the measurement
result LAeq60‘+k1.
Type of Max. level Requirements
live event
3 100 dB - Sound level recording
- Results to store for 30 days
- Level warning to visitors
- Hearing protection distributed
These levels are shown in the numeric result page:
- Chill out zone < 85 dB(A)
LAeq5”+k1 Time-averaged sound pressure level LAeq
2 96 dB - Sound level monitoring
with correction value k1 and a moving time
- Level warning to visitors
window of 5 seconds.
- Hearing protection distributed
LAeq60’+k1 Time-averaged sound pressure level LAeq
1 93 dB - Sound level monitoring
with correction value k1 and a moving time
window of 60 minutes.

• Maximum peak level LAFmax = 125 dB LAFmax+k1 Maximum sound pressure level LAFmax
with correction value k1.

306
 Appendix

The following sound levels are displayed in the real-time ana- In accordance with V-NISSG, all sound levels
lyzer page: are measured, displayed and logged to SD Card
LZFhold3 For tracing of feedback frequencies. The automatically. The settings are locked, which
peak hold time is set to 3 seconds. ensures that the correct parameters are mea-
sured.
LZFlive Actual real-time spectra.
The profile #V-NISSG 100dB&Audio includes
the recording of Compressed+AGC wav-files.

How to Measure
• Select the page KSET with the rotary wheel .
• Measure the correction value k1 as described in the chapter
Sound Level Meter: Correction Value KSET. (k2 is not required
for V-NISSG)
• Press the start button .
• The icon LOG flashes during the ongoing measurement. In
the case where the profile #V-NISSG 100dB&Audio has
been selected the icon AUD flashes, indicating the additional
audio wav-file logging.
• During the measurement you can monitor the actual sound
level LAeq5”+k1 in order to remain below the permitted lim-
its; alternatively you may monitor the spectrum analyzer for
tracing possible feedback frequencies.
• Press stop to finish the measurement.

307
 Appendix

Limits Appendix 3: Description Sound Levels

This profile is configured with the following limits, which trig-
ger the lights on the limit button and external Digital I/O Adapt-
er. This facilitates a quick response to sound levels that exceed
these limits. A-Frequency Weighting Filter in accordance with
IEC 61672
Applicable for most common sound pressure level
measurements, compensating for human hearing
perception at lower sound pressure levels.

C-Frequency Weighting Filter in accordance with

IEC 61672
Applicable for very high sound pressure levels,
compensating for human hearing perception at
high sound pressure levels; typically used for mea-
surement of peak values, e.g. LCpeak

Capture
This selection offers the reference curve, which has
been previously stored with Capture in the spec-
Measurement Results trum analyzer of the SLMeter function.
You may import the log files into a report generator soft- Application example:
ware based on MS Excel, providing automatically-completed • Comparing the performance of the left and right
live event reports with noise level charts. The report genera- speakers in a live event sound setup.
tor software is a free download on the support website at
https://my.nti-audio.com for all registered XL2 customers.

308
 Appendix

Sound Exposure Level Moving Time-Average Sound Level or

The sound exposure level LAE characterizes the Moving Equivalent Continuous Sound Level
total energy content of a signal and corresponds With selectable time window from one second
to the LAeq normalized to one second. The sound up to one hour, four individual levels can be con-
exposure level is measured for example to compare figured. The moving time-average sound level is a
noise events with different time durations. The LAE Leq based on a moving time window. This level is
reports the amount of noise from an event such as also called “running Leq,T”, “gliding Leq,T” or “slid-
an individual aircraft fly-over. An earlier used level ing Leq,T”.
name is SEL.
LAE = LAeq + 10 x log (time in seconds) The measurement result is updated every second
for the first 60 seconds. Afterwards the update rate
Time-Average Sound Level or is every five seconds. This is an example:
Equivalent Continuous Sound Level in accor-
dance with IEC 61672
10h 00min 00sec Start of XL2 measurement
Octave-band Time-Average Sound Level or
Equivalent Continuous Sound Level in accor- 10h 00min 05sec Leq5” = Leq of the 5 seconds
dance with IEC 61672
with selectable 63 Hz or 125 Hz octave-band level 10h 00min 06sec Leq5” = Leq of the time win-
for low frequency noise monitoring; in case of a dow from 10h 00min 01sec to
selected 1/3 octave resolution in the RTA window, 10h 00min 06sec
these levels are calculated by summing the corre-
sponding one-third-octave levels. 10h 00min 07sec Leq5” = Leq of the time win-
dow from 10h 00min 02sec to
10h 00min 07sec

309
 Appendix

Application example: Impulse Time Weighting

• Display the moving Leq over 5 seconds in accor- Time constant attack t = 35 ms; time constant de-
dance with DIN15905 cay t = 1500 ms; the time weighting is an exponen-
• Measure the moving Leq over 60 minutes in ac- tial function of time, which defines how changes
cordance with V-NISSG of the instantaneous sound pressure level are av-
eraged for useful sound pressure level results. The
Fast Time Weighting measurement results are shown accurately for
Time constant t = 125 ms; the time weighting is sound sources with a minimum length of 0.1 sec-
an exponential function of time, which defines onds. Impulse time weighting is used for impulsive
how changes of the instantaneous sound pressure sound sources.
level are averaged for useful sound pressure level
results. The measurement results are shown accu- Impulse Penalty ImpPenalty
rately for sound sources with a minimum length of Impulsive penalty in accordance with BS4142:2014
0.5 seconds. The decay rate is 34.7 dB/s. Fast time and NordTest ACOU 112. The LAF is sampled with
weighting is typically used for common sound level a time interval of 12 ms. The penalty is calculated
measurements. as follows:
Penalty KI= 1.8 * (Prominence P - 5) for P > 5
Holding Maximum Level P=3*lg(onset rate[dB/s]) + 2*lg(level difference[dB])
For tracing of feedback frequencies in the RTA page.
The hold time can be set to 3, 5 or 10 seconds. The Prominence P is designed to give a maximum
around 15; concluding the maximum impulse pen-
alty is 18 dB.

310
 Appendix

Correction Value k1 Peak Level

The correction value k1 is based on an LAeq mea- Application example:
surement. It is measured or manually set in the Measure LCpeak in accordance with DIN15905
page KSET of the sound level meter function.
The RTA spectrum analyzer measures the true peak
Correction Value k2 level with the optional Extended Acoustic Pack. The
The correction value k2 is based on either LCeq or peak hold time can be set to 0, 1 or 5 seconds.
LCpeak measurement. It is measured or manually
set in the page KSET of the sound level meter func- Percentile Sound Level - Level Statistics
tion. The statistical distribution of sound pressure levels
is commonly used for environmental noise analy-
Parameter live sis, such as road traffic or community noise assess-
Actual current sound pressure level. ments. For example, LAFxx% is the noise level
exceeded during xx% of the measurement period;
Parameter max e.g., LAF90% is the noise level exceeded during
Maximum sound level of the measurement cycle. 90% of the measurement period.

Parameter min Please see the specifications at chapter Technical

Minimum sound level of the measurement cycle. Data XL2: Functions of Extended Acoustic Pack
(optional) in this manual.
Correction Value off
No correction value, default setting. Previous Level
Applicable for timer mode Repeat or Repeat Syn-
chronized; displays the selected sound pressure
level of the last measurement cycle.

311
 Appendix

Slow Time Weighting Parameter T5eq

Time constant t = 1 second; the time-weighting is Time-average Clock-Impulse Maximum Level
an exponential function of time, which defines how (Taktmaximalpegel) LAFT5eq in accordance with
changes of the instantaneous sound pressure level DIN 45645-1 and DIN 45657.
are averaged for useful sound level results. The de-
cay rate is 4.3 dB/s. Inverted X-Curve
In the film and recording industry an X curve is also
Parameter T3 known as a wide-range curve, e.g., used for cinema
Clock-Impulse Maximum Level (Taktmaximalpegel) installations conforming to SMPTE ST 202:2010 or
LAFT3 in accordance with DIN 45645-1; maximum ISO 2969:2015 @ 500 seats.
sound pressure level measured with frequency
weighting A and time weighting F within a time in- Z-frequency weighting in accordance with
terval of 3 seconds. IEC 61672 (= flat frequency response, no filter)
Overall sound pressure level, all sound signal com-
Parameter T3eq ponents are included; required for special applica-
Time-average Clock-Impulse Maximum Level tions.
(Taktmaximalpegel) LAFT3eq in accordance with
DIN 45645-1 and DIN 45657. Sound Pressure Level Lp
Lp is a commonly used abbreviation for sound pres-
Parameter T5 sure level (p for pressure); for example, Lw is used
Clock-Impulse Maximum Level (Taktmaximalpegel) for Sound Power Level
LAFT5 in accordance with DIN 45645-1; maximum
sound pressure level measured with frequency
weighting A and time weighting F within a time in-
terval of 5 seconds.

312
 Appendix

Appendix 4: Common Sound Levels

Display Application Setting

LAE Sound Exposure Level

->
The sound exposure level LAE characterizes the total energy
content of a signal and corresponds to the LAeq normalized to
one second. The sound exposure level is measured for example
to compare noise events with different time durations. The LAE
reports the amount of noise from an event such as an individual
aircraft fly-over. An earlier used level name is SEL.
LAE = LAeq + 10 x log (time in seconds)

LAeq Time-Average Sound Pressure Level or

-> ->
Equivalent Continuous Sound Pressure Level
Averaged sound level over time with A frequency weighting.

LAeq_dt Level LAeq_dt “delta t” in report

Level of the preset logging interval in the LOG-menu; e.g. Log-
ging interval = 1 second, then LAeq_dt is the time averaged level
of the past 1 second.

313
 Appendix

LAeq+k1 Time-Average Sound Pressure Level with Correction Value

-> ->
The actual measurement position often differs to the loudest posi-
tion of the live event. Thus, the correction value k1 is the correc-
tion value of LAeq between the loudest position and the actual
measurement position, measured using pink noise. The correc-
tion value k1 is measured or manually set in the page KSET of the
sound level meter function.

LAeqxx Moving Time-Average Sound Pressure Level

-> -> ->
Measurement of the moving sound level over time Leq with A-
weighting frequency and F-weighting time responses; the param-
eter xx is user-defined from one second up to one hour. This level
is also called “running Leq,T”, “gliding Leq,T” or “sliding Leq,T”.

Four individual levels can be configured, e.g.

• 5 seconds for live sound monitoring
• 10 minutes (in accordance with the French standard)
• 15 minutes (in accordance with the British standard)
• 60 minutes (in accordance with V-NISSG)

LAeq20-200 Time-Average Sound Pressure Level 20 - 200 Hz

->
Summed time-averaged sound pressure level over time with
A frequency weighting of the third-octave frequency bands
20 - 200 Hz.

314
 Appendix

LAeq60’+k1 Moving Time-Average Sound Pressure Level with

-> -> ->
Correction Value k1
The actual measurement position often differs to the loudest po-
sition of the live event. Thus, the correction value k1 is the cor-
rection value of LAeq60’M between the loudest position and the
actual measurement position, measured using pink noise. The
correction value k1 is measured or manually set in the page KSET
of the sound level meter function.
Application: Measurements in accordance with V-NISSG

LAF Actual Sound Pressure Level

-> -> ->
Sound pressure level with A frequency weighting and F time
weighting, compensating for human hearing perception at lower
sound pressure levels; applicable at levels lower than 100 dB.

LAFmax Maximum Sound Pressure Level

-> ->
Measures the maximum environmental noise level during the
measurement period.

LAFmax_dt Maximum Sound Pressure Level “delta t” in report

Maximum level of the preset logging interval in the LOG-menu,
e.g. 1 second.

LAFmin Minimum Sound Pressure Level

-> ->
Measures the minimum environmental noise level during the
measurement period.
315
 Appendix

LAFmin_dt Minimum Sound Pressure Level “delta t” in report

Minimum level of the preset logging interval in the LOG-menu,
e.g. 1 second.

LAFxx% Percentile Sound Pressure Level

-> ->
The statistical distribution of sound pressure levels is commonly
used for environmental noise analysis, such as road traffic or com-
munity noise assessments. For example LAFxx% is the noise
level exceeded during xx% of the measurement period; e.g.,
LAF90% is the noise level exceeded during 90% of the measure-
ment period.

Please see the specifications at chapter Technical Data XL2: Func-

tions of Extended Acoustic Pack (optional) in this manual.

Sound Level [dB] vs Time

90 LAF10% = 88.8dB
LAeq= 84.2dB

80
LAF50%= 76.4dB

70
LAF90%= 66.6dB

60
Time [seconds]

316
 Appendix

LCeq Time-Average Sound Pressure Level or

-> ->
Equivalent Continuous Sound Pressure Level
Averaged sound level over time with C frequency weighting.

LCPK Peak Sound Level

-> ->
Peak sound level with C frequency weighting. Measures the peak
level. High peak levels can damage the human hearing.

LCPKmax Maximum Peak Sound Level

-> -> ->
Maximum peak sound level with C frequency weighting. Mea-
sures the peak level. High peak levels can damage the human
hearing.

LCPK_dt Maximum Peak Sound Level „delta t” in report

Maximum peak sound level with C frequency weighting of the
preset logging interval in the LOG-menu, e.g. 1 second.

LCPK+k2 Peak Sound Level with Correction Value

-> ->
The actual measurement position often differs to the loudest posi-
tion of the live event. Thus, the correction value k2 is the correc-
tion value of LCPK between the loudest position and the actual
measurement position, measured using pink noise. The correc-
tion value k2 is measured or manually set in the page KSET of the
sound level meter function.

317
 Appendix

LEX Noise Exposure Level LEX

-> ->
The Noise at Work Directive 2003/10/EC lays down minimum re-
quirements for the protection of workers from risks to their health
and safety arising or likely to arise from exposure to noise and in
particular the risk to hearing.
• Steady noise LEX,8h = LAeq: (applies to LAS, deviation < 5 dB)
LAeq measured over a short time equals LEX,8h; the following
formula applies for a measurement period < 8 hours:
LEX,8h = LAeq + 10 x log ( T / 8 hours )
• Steady noise with stepped level variations:
Measure LAeq at the different levels and enter the data with
the corresponding exposure time in the NTi Audio noise expo-
sure level post-processing form; the LEX,8h will be calculated
and displayed.
• Varying noise levels:
LEX,8h = LAeq measured for 8 hours

The exposure limit values and respective actions are:

LEX, 8h LCpeak Action
Lower limit value 80 dB(A) 135 dB The employer shall make individual hearing protectors available
to workers
Upper limit value 85 dB(A) 137 dB Hearing protectors shall be used
Exposure limit 87 dB(A) 140 dB The attenuation characteristics of the hearing protectors worn
must adequately reduce the levels below this limit

318
 Appendix

Appendix 5: Vibration Meter Functions Peak-peak Level

Measurement result is based on peak-peak level
Acceleration a • Peak-peak level a(PP) = a(Pk) * 2
in units m/s2, g, in/s2, dB • Peak-peak level v(PP) = v(Pk) * 2
La [dB] = 20*log (a / 10-6) • Peak-peak level d(PP) = d(Pk) * 2

Velocity v Moving Time-Average Level or

in units m/s, in/s and dB; Moving Equivalent Continuous Level
Velocity is calculated based on the acceleration a with selectable time window 1, 2, 4 or 8 seconds.
and the frequency f: v = a / (2 * π * f)
Lv [dB] = 20*log (v / 10-9)
Clock-Impulse Maximum Level
Displacement (Taktmaximalpegel)
in units m, in, dB; Maximum velocity during a periodic 30 seconds
Displacement is calculated based on the accelera- interval with time weighting F in accordance with
tion a and the frequency f: d = a / (2 * π * f)2 DIN 4150-2.
Ld [dB] = 20*log (d / 10-12)
Peak Particle Velocity PPV
RMS level Ground or blast vibration amplitude is often mea-
Measurement result is based on RMS sured as particle velocity or the speed at which a
particle vibrates. This is quantified as peak particle
Peak level velocity PPV in the units [mm/s] or [in/s]. PPV
Measurement result is based on peak level equals the level type vel Pk on the XL2.
• Peak level a(Pk) = √2 * a
• Peak level v(Pk) = √2 * v
• Peak level d(Pk) = √2 * d

319
 Appendix

Details IEC 61672 & IEC 61260 Configuration “Microphone Detached”

• XL2-TA Sound Level Meter
- Hardware version: D2, E0, E1
The XL2-TA Analyzer, with the M2230 measurement micro- - Firmware version 4.71
phone, fully complies with the standards IEC 61672:2013, • M2230 Measurement Microphone, consisting of
IEC 61672:2003, IEC 61260:2014 and IEC 61260:2003 as an - Microphone Preamplifier MA220
integrating class 1 Sound Level Meter with A, C, Z frequency - Microphone Capsule MC230 or MC230A
weighting and fast/slow time weighting. The impulse time • M2340 Measurement Microphone, consisting of
weighting is optionally available with the Extended Acoustic - Microphone Preamplifier MA230
Package. - Microphone Capsule MC230A
• ASD Cable, 5 meter or 10 meter or 20 meter
The type approval applies to the sound level meter in accor- • Class 1 Sound Calibrator CAL200
dance with IEC 61672 and the Octave/Third-Octave measure- • Optional
ment in accordance with IEC 61260. Attention should be given - Optional: Extended Acoustic Pack
to the following recommendations on the environment and the - NTi Audio Mains Power Adapter Exel Line
configuration. - NTi Audio Microphone Clamp MH01
- NTi Audio Windscreen, 50 mm
Environment - NTi Audio Windscreen, 90 mm
Persons and objects that are located in the sound field during - XL2 Input Keypad
the measurement have an absorbing, reflecting or shielding
impact on the sound field and may therefore compromise the With the microphone connected by the ASD Cable, the ana-
measurement result. Consequently, such objects should be re- lyzer can be held in your hand during the measurement. This
moved from the sound field where appropriate. The measure- offers the convenience of watching the measurement values
ment microphone should be mounted on a tripod. The operator as they occur.
should remain as far away as possible behind the microphone
during the measurement.

320
 Appendix

Configuration “Microphone Attached” Configuration “Outdoor Microphone Detached”

• XL2-TA Sound Level Meter • XL2-TA Sound Level Meter
- Hardware version: D2, E0, E1 - Hardware version: D2, E0, E1
- Firmware version 4.71 - Firmware version 4.71
- Shroud MXA01 • M2230 Measurement Microphone, consisting of
• M2230 Measurement Microphone, consisting of - Microphone Preamplifier MA220
- Microphone Preamplifier MA220 - Microphone Capsule MC230 or MC230A
- Microphone Capsule MC230 or MC230A • M2340 Measurement Microphone, consisting of
• M2340 Measurement Microphone, consisting of - Microphone Preamplifier MA230
- Microphone Preamplifier MA230 - Microphone Capsule MC230A
- Microphone Capsule MC230A • Weather Protection WP30 with bird spike BS01
• Class 1 Sound Calibrator CAL200 • ASD Cable, 5 meter or 10 meter or 20 meter
• Optional • Class 1 Sound Calibrator CAL200
- Optional: Extended Acoustic Pack • Optional
- NTi Audio Mains Power Adapter Exel Line - Optional: Extended Acoustic Pack
- NTi Audio Windscreen, 50 mm - NTi Audio Mains Power Adapter Exel Line
- NTi Audio Windscreen, 90 mm - XL2 Input Keypad
- XL2 Input Keypad - Dehumidifier for Weather Protection WP30

• There are no correction values required for

the configuration “Outdoor Microphone De-
tached” at vertical noise incidents.
There are no correction values required for • Activate the corresponding correction in the
these configurations. Calibration menu for “Outdoor Microphone
Detached” at horizontal noise incidents.

321
 Appendix

General Information switching on the power. This assumes that the devices have
been allowed to reach equilibrium with the prevailing ambient
Reference Sound Pressure Level environment before switching on the power.
The reference sound pressure level is 114 dBSPL relative to
20 mPa. Insertion of Electrical Signals
(Refer IEC61672-1 paragraphs 5.1.15, 9.3g)
Reference Level Range The capsule replacement NTI-K65-15 can be used to insert
The reference level range is MID, 20 - 120 dBSPL electrical signals to the preamplifier MA220. The device pro-
vides at one side a contact that corresponds to the center con-
Reference Orientation tact of the replaced microphone capsule, at the other side a
The microphone reference point is located in the middle of the BNC-plug for the electrical signals. The impedance at the out-
microphone membrane. The 0° reference orientation and the put of the device is 15 pF with a maximum deviation of ±1 pF.
orientation of the membrane’s surface normal is identical. The electrical noise floor is measured by shorting the con-
tacts of the BNC plug. Before the NTI-K65-15 can be mount-
Verified Frequency Range ed to the preamplifier MA220, the microphone capsule must
20 Hz to 20 kHz first be detached. The nominal sensitivity S of the capsule is
S = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
Greatest Peak-To-Peak Voltage at the Electric Input require that the sensitivity in the calibration menu is manually
(Refer IEC61672-1 paragraphs 5.1.16, 9.3.i) adjusted to S = 42 mV/Pa.
The highest sound pressure level at the M2230 microphone
with a sensitivity of S = 42 mV/Pa is 143.5 dB. The maximum electrical input voltage is 36 Vpp. The attenu-
ation between the device and the XLR input of the XL2-TA is
Initial Time Interval after Power On (IEC61672-1, 5.1.18) 0.78 dB at a reference frequency of 1 kHz. A 1 kHz signal with
The XL2-TA Sound Level Meter and M2230 microphone meet 459 mVrms level is required at the input of the device, to sub-
the given specifications for the electro-acoustical response af- stitute the signal of a microphone capsule with the sensitivity
ter an initial time interval of no more than one minute following 42 mV/Pa at a reference level of 114 dBSPL.

322
 Appendix

Output (Refer IEC61672-1 paragraphs 5.16.1, 9.2.5p) No Limit on Operational Environment

The instrument provides no electrical analog or digital outputs (Refer IEC61672-1 paragraphs 6.3.2, 9.2.7a)
for measurements. There are no restrictions in place for parts or components,
which would limit the operational environment.
Typical Time Interval Needed to Stabilize after Changes in
Environmental Conditions (IEC61672-1, 6.1.2, 9.3l) Exposure to Electrostatic Discharges
Recommended time interval for stabilizing the sound level me- (Refer IEC61672-1 paragraphs 6.5.2, 9.2.7b)
ter after changes in environmental conditions, prior to perform- Heavy electrostatic discharges directly to the instrument’s
ing any measurements: connector or keyboard may interrupt the operation. The XL2-TA
either switches off or freezes at the last valid measurement
value. In such a case re-start the instrument. If the data logging
Change in the environmental condition Time Interval had been active prior the interrupt, the log file may contain a
gap. However, the acquired results can be identified correct-
ly as each one is saved together with its own individual time
Temperature ±5 °C 15 minutes stamp.

Temperature ±20 °C 30 minutes Exposure to AC Power and Radio Frequency Fields

(Refer IEC61672-1 paragraphs 6.6.1, 9.2.7c)
Air pressure ±5 kPa 15 seconds The sound level meter complies with the requirements of the
standards IEC61672-1:2013 and IEC61260-1:2014 regarding
Humidity ±30% 15 minutes immunity against high frequency fields or mains power fields
from 50 to 60 Hz.

The time intervals apply, for instance, after moving from a cold
into a warm room, and assume that combinations of air tem-
perature and relative humidity do not yield a dew point greater
than +39 °C or less than –15 °C.

323
 Appendix

Impact of Electromagnetic Fields Influence of the ASD Cable

If the device is exposed to electromagnetic fields of 10 V/m, (Refer IEC61672-1 paragraphs 7.1, 9.2.6b)
the measurement of sound levels below 74 dB is not speci- The ASD Cable serves as connection cable between the
fied. If the electromagnetic fields exceed 10 V/m, the exposed XL2-TA sound level meter and the microphone in the detached
instrument is not specified in any level range. configuration. There are no correction values required for this
configuration.
Susceptibility to AC Power and Radio Frequency Fields
(Refer IEC61672-1 paragraphs 6.6.3, 9.3o) Influence of Mechanical Vibrations
The device has the greatest susceptibility to AC power fre- Mechanical vibrations with 1 m/s2 acceleration perpendicular
quency fields, if the direction of the magnetic field is the same to the membrane of the microphone, will raise the lower limit
as the orientation of the microphone axis. of the linear operating range to 71 dB (A-weighted) for the fre-
The device has the greatest susceptibility to radio frequency quencies 31,5 Hz, 63 Hz, 126 Hz, 250 Hz, 500 Hz, 630 Hz,
fields in the lowest measurement range, if the surface normal 800 Hz and 1000 Hz. Mechanical vibrations with 1 m/s2 accel-
of the display and the direction of the incoming radio frequency eration parallel to the membrane of the microphone, will raise
field are parallel to each other and the power supply is con- the lower limit of the linear operating range to 68 dB (A-weight-
nected. In this case, the sound level meter should be operated ed) for the frequencies 31,5 Hz, 63 Hz, 126 Hz, 250 Hz, 500 Hz,
without a power supply. The configuration with the greatest 630 Hz, 800 Hz and 1000 Hz.
radio-frequency emissions levels is provided by connecting the
mains power adapter to the sound level meter. Modes of Operation and Accessories
The greatest susceptibility to radio frequency fields is indepen-
Measuring Low-Level Sound Fields det of operation mode or connected accessories.
(Refer IEC61672-1 paragraphs 5.6.5, 9.2.5d)
If the sound level is very low, the measurement result is af- Volume of Measurement Microphone M2230
fected by the noise floor of the sound level meter. The speci- • Equivalent Diaphragm Volume = 50 mm3
fied configuration complies with class 1 within the given linear • Volume between grid and membran/housing = 92.5 mm3
measuring range. • Calibrator Load Volume = 142.5 mm3

324
 Appendix

Class 1 Sound Calibrator Accessory

(Refer IEC61672-1 paragraphs 5.2.1, 5.2.7, 9.3d) Input Keypad
The Input Keypad has no effect on measured sound pressure
If an obligatory calibration is required for the sound level meter, levels of the instrument.
in accordance with the type approval, then the Class 1 Sound
Calibrator CAL200 should be used.

Technical Details
• Type: Larson Davis CAL200
• Level correction: -0.1 dB
• Calibration frequency: 1 kHz (= reference frequency)
• Calibration level: 114 dB (= reference sound pressure level)

Details for Calibration

The calibration has to be executed according to the instructions
given in chapter “Calibration”. Ensure that the calibrator is set
to 114 dB.

Add the free-field correction values to the reference sound

pressure level, and enter the result into the XL2-TA under “Cali-
bration Level“.

325
 Appendix

Level Linearity
(Refer IEC61672-1 paragraphs 5.5.3, 5.5.9, 9.2.2e, 9.3e, 9.3f).
All values refer to Sref = 42 mV/Pa*. The starting levels for the
level linearity tests are listed in the following tables:

Level range: Low Level range: Mid

Frequency Frequency
[dB] LAt* LCt* LZt* LAeqT* LAE* LCpeak* [dB] LAt* LCt* LZt* LAeqT* LAE* LCpeak*
(tint = 10s) (tint = 10s)

31,5 from 24 from 27 from 30 from 24 from 34

31,5 from 31 from 32 from 35 from 31 from 41
to 68 to 105 to 108 to 68 to 78 to 86 to 123 to 126 to 86 to 96
Hz starting 54 starting 94 starting 94 starting 54 starting 54 Hz starting 54 starting 114 starting 114 starting 54 starting 54

from 24 from 27 from 30 from 24 from 34 from 41 from 31 from 32 from 35 from 31 from 41 from 38
1 kHz to 108 to 108 to 108 to 108 to 118 to 111 1 kHz to 126 to 126 to 126 to 126 to 136 to 129
starting 94 starting 94 starting 94 starting 94 starting 104 starting 114 starting 114 starting 114 starting 114 starting 124

from 24 from 27 from 30 from 24 from 34 from 31 from 32 from 35 from 31 from 41
4 kHz to 109 to 107 to 108 to 109 to 119 4 kHz to 127 to 126 to 126 to 127 to 137
starting 94 starting 94 starting 94 starting 94 starting 104 starting 114 starting 114 starting 114 starting 114 starting 124

from 24 from 27 from 30 from 24 from 34 from 31 from 32 from 35 from 31 from 41
8 kHz to 107 to 105 to 108 to 107 to 117 8 kHz to 126 to 123 to 126 to 126 to 135
starting 94 starting 94 starting 94 starting 94 starting 104 starting 114 starting 114 starting 114 starting 114 starting 124

12,5 from 24 from 27 from 30 from 24 from 34

12,5 from 31 from 32 from 35 from 31 from 41
to 104 to 102 to 108 to 104 to 114 to 122 to 120 to 126 to 122 to 132
kHz starting 94 starting 94 starting 94 starting 94 starting 104 kHz starting 114 starting 114 starting 114 starting 114 starting 124

* If the sensitivity Sx deviates from the given data, a correction value of 20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB

326
 Appendix

Level range: High

Frequency Sound pressure levels, which continiously exceed the specified

[dB] LAt* LCt* LZt* LAeqT* LAE* LCpeak* linear measurement range and overload the microphone pream-
(tint = 10s) plifier, may cause in extreme cases a displayed level below the
31,5 from 53 from 51 from 56 from 53 from 63 actual sound pressure level.
to 98 to 137 to 137 to 98 to 108
Hz starting 94 starting 114 starting 114 starting 94 starting 94

from 53 from 51 from 56 from 53 from 63 from 65

1 kHz to 137 to 137 to 137 to 137 to 147 to 140
starting 114 starting 114 starting 114 starting 114 starting 124

from 53 from 51 from 56 from 53 from 63

4 kHz to 138 to 137 to 137 to 138 to 148
starting 114 starting 114 starting 114 starting 114 starting 124

from 53 from 51 from 56 from 53 from 63

8 kHz to 136 to 137 to 137 to 136 to 146
starting 114 starting 114 starting 114 starting 114 starting 124

12,5 from 53 from 51 from 56 from 53 from 63

to 133 to 131 to 137 to 133 to 143
kHz starting 114 starting 114 starting 114 starting 114 starting 124

327
 Appendix

Level Linearity of Octaveband-Spectrum

in accordance with IEC 61260.
All values refer to Sref = 42 mV/Pa*.

Nominal Level Range

Frequency
LOW MID HIGH
Hz
20 45-108 dB 20-126 dB 32-137 dB
31.5 25-108 dB 20-126 dB 32-137 dB
63 23-108 dB 20-126 dB 32-137 dB
125 14-108 dB 17-126 dB 33-137 dB
250 13-108 dB 15-126 dB 34-137 dB
500 13-108 dB 15-126 dB 36-137 dB
1000 15-108 dB 16-126 dB 39-137 dB
2000 17-108 dB 18-126 dB 41-137 dB
4000 19-108 dB 20-126 dB 44-137 dB
8000 19-108 dB 23-126 dB 47-137 dB
16000 18-108 dB 28-126 dB 51-137 dB

The sampling rate of the filters is 48 kHz.

* If the sensitivity Sx deviates from the given data, a correction value of

20*log(Sref/Sx) has to be added.
Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB

328
 Appendix

Level Linearity of Third-Octaveband-Spectrum

in accordance with IEC 61260.
All values refer to Sref = 42 mV/Pa*.

Nominal Level Range Nominal Level Range

Frequency Frequency
LOW MID HIGH LOW MID HIGH
Hz Hz
12.5 48-108 dB 17-126 dB 29-137 dB 1600 11-108 dB 12-126 dB 35-137 dB
16 46-108 dB 17-126 dB 29-137 dB 2000 13-108 dB 13-126 dB 36-137 dB
20 43-108 dB 17-126 dB 29-137 dB 2500 13-108 dB 14-126 dB 37-137 dB
25 41-108 dB 16-126 dB 29-137 dB 3150 14-108 dB 14-126 dB 38-137 dB
31.5 37-108 dB 15-126 dB 29-137 dB 4000 14-108 dB 15-126 dB 39-137 dB
40 28-108 dB 14-126 dB 29-137 dB 5000 15-108 dB 16-126 dB 40-137 dB
50 23-108 dB 13-126 dB 29-137 dB 6300 15-108 dB 17-126 dB 41-137 dB
63 19-108 dB 12-126 dB 29-137 dB 8000 15-108 dB 18-126 dB 42-137 dB
80 11-108 dB 11-126 dB 29-137 dB 10000 15-108 dB 19-126 dB 43-137 dB

100 9-108 dB 11-126 dB 29-137 dB 12500 14-108 dB 21-126 dB 44-137 dB

125 8-108 dB 10-126 dB 29-137 dB 16000 13-108 dB 23-126 dB 48-137 dB
160 8-108 dB 10-126 dB 29-137 dB 20000 13-108 dB 26-126 dB 50-137 dB

200 8-108 dB 10-126 dB 29-137 dB

250 7-108 dB 10-126 dB 29-137 dB
315 8-108 dB 10-126 dB 30-137 dB The sampling rate of the filters is 48 kHz.
400 8-108 dB 11-126 dB 30-137 dB
500 8-108 dB 11-126 dB 31-137 dB
630 9-108 dB 11-126 dB 31-137 dB * If the sensitivity Sx deviates from the given data, a correction value of
800 9-108 dB 11-126 dB 32-137 dB 20*log(Sref/Sx) has to be added.
1000 10-108 dB 11-126 dB 34-137 dB Example: Sx = 45 mV/Pa -> correction value = 20*log(42/45) = -0.6 dB
1250 11-108 dB 12-126 dB 35-137 dB

329
 Appendix

Self-generated Noise with Microphone

(Refer IEC61672-1 paragraphs 5.6.1 to 5.6.4, 9.2.5o)

Self-generated noise with electrical input device @ S = 42 mV/Pa

Frequency- Level range [dB]
weighting low mid high

Z 22 23 46

A 11 19 43

C 14 18 42

Self-generated noise with M2230 microphone @ S = 42 mV/Pa

Frequency- Level range [dB]
weighting low mid high

Z 23 25 46

A 17 21 43

C 20 22 42

The averaging time is 30 seconds for all measurements.

330
Appendix

331
 Appendix

Frequency Response Corrections

(Refer IEC61672-1 paragraphs 5.2.4, 5.2.5, 5.2.6 und 9.2.4d)
The below listed wind screen corrections may be selected in the XL2 Sound Level Meter.
The listed uncertainty applies for all here listed measurements and corrections. Its calculated for a level of confidence of 95% with
a coverage factor k=2. It represents the maximum permitted expanded uncertainty in accordance with IEC 62585.

Nominal Actual 0° Free-field 0° Free-field Housing Reflection Impact of 0° Free-field Impact of 0° Free-field Measure-
Frequency Frequency Frequency Correction and Microphone 50 mm Correction with 90 mm Correction with ment
Response Diffraction Wind 50 mm Wind 90 mm Uncertainty
Correction Screen Wind Screen Screen Wind Screen
Hz Hz dB dB dB dB dB dB dB dB
63 63.10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
125 125.89 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
250 251.19 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
315 316.23 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20
400 398.11 0.0 0.0 0.0 0.0 0.0 0.1 -0.1 0.20
500 501.19 0.0 0.0 0.0 0.0 0.0 0.1 -0.1 0.20
630 630.96 0.0 0.0 0.0 0.0 0.0 0.1 -0.1 0.20
800 794.33 0.0 0.0 0.0 0.0 0.0 0.2 -0.2 0.20
1000 1000.00 0.0 0.0 0.0 0.0 0.0 0.2 -0.2 0.20
1060 1059.25 0.0 0.0 0.0 0.0 0.0 0.2 -0.2 0.20
1120 1122.02 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1180 1188.50 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1250 1258.93 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20

332
 Appendix

Nominal Actual 0° Free-field 0° Free-field Housing Reflection Impact of 0° Free-field Impact of 0° Free-field Measure-
Frequency Frequency Frequency Correction and Microphone 50 mm Correction with 90 mm Correction with ment
Response Diffraction Wind 50 mm Wind 90 mm Uncertainty
Correction Screen Wind Screen Screen Wind Screen
1320 1333.52 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1400 1412.54 0.0 0.0 0.0 0.1 -0.1 0.2 -0.2 0.20
1500 1496.24 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1600 1584.89 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1700 1678.80 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1800 1778.28 0.0 0.0 0.0 0.1 -0.1 0.3 -0.3 0.20
1900 1883.65 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2000 1995.26 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2120 2113.49 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2240 2238.72 0.0 0.0 0.0 0.2 -0.2 0.3 -0.3 0.20
2360 2371.37 0.0 0.0 0.0 0.3 -0.3 0.3 -0.3 0.20
2500 2511.89 0.0 0.0 0.0 0.3 -0.3 0.2 -0.2 0.20
2650 2660.73 0.0 0.0 0.0 0.3 -0.3 0.1 -0.1 0.20
2800 2818.38 0.0 0.0 0.0 0.3 -0.3 0.1 -0.1 0.20
3000 2985.38 0.0 0.0 0.0 0.4 -0.4 0.0 0.0 0.20
3150 3162.28 0.0 0.0 0.0 0.4 -0.4 -0.1 0.1 0.20
3350 3349.65 0.0 0.0 0.0 0.4 -0.4 -0.2 0.2 0.20
3550 3548.13 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.20
3750 3758.37 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.20
4000 3981.07 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.20
4250 4216.97 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30

333
 Appendix

Nominal Actual 0° Free-field 0° Free-field Housing Reflection Impact of 0° Free-field Impact of 0° Free-field Measure-
Frequency Frequency Frequency Correction and Microphone 50 mm Correction with 90 mm Correction with ment
Response Diffraction Wind 50 mm Wind 90 mm Uncertainty
Correction Screen Wind Screen Screen Wind Screen
4500 4466.84 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
4750 4731.51 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
5000 5011.87 0.0 0.0 0.0 0.6 -0.6 -0.1 0.1 0.30
5300 5308.84 0.0 0.0 0.0 0.5 -0.5 -0.2 0.2 0.30
5600 5623.41 0.0 0.0 0.0 0.5 -0.5 -0.3 0.3 0.30
6000 5956.62 0.0 0.0 0.0 0.4 -0.4 -0.4 0.4 0.30
6300 6309.57 0.0 0.0 0.0 0.3 -0.3 -0.4 0.4 0.30
6700 6683.44 0.0 0.0 0.0 0.3 -0.3 -0.4 0.4 0.30
7100 7079.46 0.0 0.0 0.0 0.2 -0.2 -0.3 0.3 0.30
7500 7498.94 0.0 0.0 0.0 0.1 -0.1 -0.3 0.3 0.30
8000 7943.28 0.0 0.0 0.0 0.1 -0.1 -0.3 0.3 0.30
8500 8413.95 0.0 0.0 0.0 0.1 -0.1 -0.4 0.4 0.45
9000 8912.51 0.0 0.0 0.0 0.1 -0.1 -0.5 0.5 0.45
9500 9440.61 0.0 0.0 0.0 0.1 -0.1 -0.6 0.6 0.45
10000 10000.00 0.0 0.0 0.0 0.1 -0.1 -0.5 0.5 0.45
10600 10592.54 0.0 0.0 0.0 0.1 -0.1 -0.6 0.6 0.45
11200 11220.18 0.0 0.0 0.0 0.1 -0.1 -0.7 0.7 0.45
11800 11885.02 0.0 0.0 0.0 0.0 0.0 -0.8 0.8 0.45
12500 12589.25 0.0 0.0 0.0 -0.2 0.2 -0.8 0.8 0.45
13200 13335.21 0.0 0.0 0.0 -0.3 0.3 -0.9 0.9 0.45
14000 14125.38 0.0 0.0 0.0 -0.5 0.5 -0.9 0.9 0.45

334
 Appendix

Nominal Actual 0° Free-field 0° Free-field Housing Reflection Impact of 0° Free-field Impact of 0° Free-field Measure-
Frequency Frequency Frequency Correction and Microphone 50 mm Correction with 90 mm Correction with ment
Response Diffraction Wind 50 mm Wind 90 mm Uncertainty
Correction Screen Wind Screen Screen Wind Screen
15000 14962.36 0.0 0.0 0.0 -0.6 0.6 -1.1 1.1 0.45
16000 15848.93 0.0 0.0 0.0 -0.6 0.6 -1.1 1.1 0.45
17000 16788.04 0.0 0.0 0.0 -0.6 0.6 -1.2 1.2 0.45
18000 17782.79 0.0 0.0 0.0 -0.6 0.6 -1.5 1.5 0.45
19000 18836.49 0.0 0.0 0.0 -0.7 0.7 -1.7 1.7 0.45
20000 19952.62 0.0 0.0 0.0 -0.9 0.9 -1.5 1.5 0.45

335
 Appendix

Frequency Weighting
Nominal Frequency Weighting Nominal Frequency Weighting
Frequency dB Frequency dB
Hz A C Z Hz A C Z
10 –70.4 –14.3 0.0 3150 +1.2 –0.5 0.0
4000 +1.0 –0.8 0.0
12.5 –63.4 –11.2 0.0
5000 +0.5 –1.3 0.0
16 –56.7 –8.5 0.0
20 –50.5 –6.2 0.0 6300 –0.1 –2.0 0.0
8000 –1.1 –3.0 0.0
25 –44.7 –4.4 0.0
10000 –2.5 –4.4 0.0
31.5 –39.4 –3.0 0.0
40 –34.6 –2.0 0.0 12500 –4.3 –6.2 0.0
16000 –6.6 –8.5 0.0
50 –30.2 –1.3 0.0
20000 –9.3 –11.2 0.0
63 –26.2 –0.8 0.0
80 –22.5 –0.5 0.0
100 –19.1 –0.3 0.0
125 –16.1 –0.2 0.0
160 –13.4 –0.1 0.0
200 –10.9 0.0 0.0
250 –8.6 0.0 0.0
315 –6.6 0.0 0.0
400 –4.8 0.0 0.0
500 –3.2 0.0 0.0
630 –1.9 0.0 0.0
800 –0.8 0.0 0.0
1000 0 0 0
1250 +0.6 0.0 0.0
1600 +1.0 –0.1 0.0
2000 +1.2 –0.2 0.0
2500 +1.3 –0.3 0.0

336
 Appendix

Directional Response (dB)

Based on the sound-incidence angle. (Refer IEC61672-1 paragraphs 5.3.1, 5.3.2 and 9.2.2b).
The impact on the directional response of the Windscreen 50 mm, Windscreen 90 mm and the Weather Protection WP30 is cal-
culated by adding the frequency response correction at 0° to the below table.
Nomi- Actual Angle in Degrees
nal Fre- Frequen-
quency cy [Hz] 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
[Hz]
250 251.19 -0.00 0.00 0.00 -0.00 0.00 -0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
315 316.23 -0.00 0.01 0.01 -0.00 0.02 -0.01 0.01 0.01 0.01 0.01 -0.01 0.01 -0.01 0.00 0.01 -0.01 0.00 0.01
400 398.11 0.00 0.01 0.01 -0.00 0.02 -0.02 -0.01 0.00 0.00 0.00 -0.01 0.01 -0.02 -0.01 0.00 -0.02 0.00 0.00
500 501.19 -0.00 -0.02 -0.02 -0.01 -0.00 -0.02 -0.02 -0.01 -0.03 -0.04 -0.04 -0.04 -0.05 -0.05 -0.02 -0.04 -0.04 -0.04
630 630.96 -0.00 -0.09 -0.11 -0.06 -0.04 0.00 0.01 -0.05 -0.05 -0.06 -0.11 -0.11 -0.13 -0.08 -0.07 -0.10 -0.11 -0.13
800 794.33 -0.00 -0.00 -0.01 -0.02 0.00 -0.00 0.02 0.00 0.00 0.00 -0.03 0.00 -0.01 0.01 0.02 -0.01 -0.03 -0.04
1000 1000.00 -0.00 0.03 0.00 -0.02 0.03 -0.02 0.00 -0.01 0.00 -0.01 -0.01 0.03 0.00 -0.01 0.04 0.01 0.02 0.03
1060 1059.25 -0.00 0.03 0.01 -0.02 0.02 -0.03 -0.01 -0.03 -0.03 -0.03 -0.04 0.00 -0.02 -0.02 0.02 -0.01 0.00 0.02
1120 1122.02 -0.00 0.02 0.01 -0.02 0.00 -0.04 -0.02 -0.05 -0.06 -0.06 -0.06 -0.05 -0.06 -0.05 -0.01 -0.03 -0.02 -0.01
1180 1188.50 0.00 0.01 0.01 -0.03 -0.02 -0.05 -0.04 -0.08 -0.09 -0.08 -0.10 -0.10 -0.12 -0.11 -0.07 -0.07 -0.06 -0.06
1250 1258.93 0.00 -0.01 -0.02 -0.06 -0.05 -0.09 -0.07 -0.14 -0.14 -0.15 -0.16 -0.17 -0.21 -0.20 -0.16 -0.16 -0.13 -0.14
1320 1333.52 -0.00 -0.02 -0.05 -0.09 -0.07 -0.12 -0.10 -0.18 -0.17 -0.21 -0.23 -0.24 -0.29 -0.27 -0.26 -0.26 -0.24 -0.22
1400 1412.54 0.00 -0.01 -0.04 -0.07 -0.04 -0.09 -0.07 -0.13 -0.12 -0.18 -0.21 -0.24 -0.29 -0.27 -0.29 -0.28 -0.31 -0.26
1500 1496.24 -0.00 0.02 0.00 -0.01 0.00 -0.03 -0.02 -0.06 -0.06 -0.11 -0.14 -0.18 -0.23 -0.26 -0.27 -0.27 -0.32 -0.27
1600 1584.89 -0.00 0.03 0.02 0.00 0.02 -0.00 0.01 -0.01 -0.02 -0.06 -0.09 -0.12 -0.17 -0.23 -0.26 -0.28 -0.30 -0.29
1700 1678.80 -0.00 0.02 0.01 0.00 0.04 0.01 0.05 0.04 0.05 0.03 0.00 -0.03 -0.07 -0.12 -0.17 -0.26 -0.25 -0.26
1800 1778.28 -0.00 0.02 0.00 0.01 0.04 0.02 0.04 0.04 0.06 0.07 0.09 0.06 0.00 -0.05 -0.06 -0.18 -0.22 -0.22
1900 1883.65 -0.00 0.00 -0.02 -0.01 0.01 0.01 0.04 0.03 0.05 0.05 0.09 0.13 0.08 0.02 0.00 -0.08 -0.17 -0.23
2000 1995.26 -0.00 0.01 -0.02 -0.03 -0.03 -0.05 -0.05 -0.08 -0.04 0.00 -0.02 0.06 0.04 0.07 0.01 -0.08 -0.12 -0.25
2120 2113.49 -0.00 0.02 -0.01 -0.05 -0.05 -0.10 -0.13 -0.18 -0.22 -0.18 -0.19 -0.10 -0.14 -0.06 -0.01 -0.17 -0.19 -0.27
2240 2238.72 0.00 0.02 -0.01 -0.06 -0.08 -0.16 -0.21 -0.25 -0.31 -0.36 -0.44 -0.37 -0.34 -0.32 -0.26 -0.26 -0.33 -0.39
2360 2371.37 -0.00 0.02 0.00 -0.03 -0.03 -0.10 -0.13 -0.22 -0.30 -0.39 -0.46 -0.51 -0.56 -0.47 -0.42 -0.40 -0.33 -0.47
2500 2511.89 -0.00 0.01 -0.00 -0.03 -0.03 -0.08 -0.08 -0.11 -0.16 -0.29 -0.44 -0.48 -0.58 -0.64 -0.52 -0.50 -0.45 -0.41
2650 2660.73 0.00 0.00 -0.01 -0.05 -0.02 -0.03 -0.01 -0.01 -0.06 -0.09 -0.21 -0.34 -0.49 -0.55 -0.62 -0.54 -0.48 -0.42
2800 2818.38 0.00 0.01 -0.01 -0.03 -0.03 -0.09 -0.10 -0.08 -0.07 -0.09 -0.16 -0.18 -0.36 -0.51 -0.58 -0.70 -0.57 -0.55

337
 Appendix

Nomi- Actual Angle in Degrees

nal Fre- Frequen-
quency cy [Hz] 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85
[Hz]
3000 2985.38 -0.00 0.00 -0.03 -0.09 -0.12 -0.19 -0.20 -0.25 -0.31 -0.31 -0.30 -0.34 -0.43 -0.52 -0.70 -0.79 -0.84 -0.73
3150 3162.28 -0.00 0.01 -0.00 -0.06 -0.06 -0.13 -0.18 -0.30 -0.36 -0.42 -0.49 -0.47 -0.51 -0.62 -0.70 -0.92 -0.95 -0.97
3350 3349.65 -0.00 0.01 0.01 0.00 -0.01 -0.06 -0.09 -0.15 -0.23 -0.37 -0.46 -0.46 -0.55 -0.55 -0.67 -0.82 -1.05 -1.01
3550 3548.13 -0.00 0.02 0.02 0.01 0.00 -0.03 0.01 0.00 -0.07 -0.18 -0.29 -0.40 -0.47 -0.50 -0.48 -0.65 -0.84 -1.08
3750 3758.37 -0.00 0.01 -0.01 -0.07 -0.08 -0.12 -0.09 -0.09 -0.10 -0.11 -0.22 -0.35 -0.49 -0.62 -0.54 -0.60 -0.78 -0.98
4000 3981.07 -0.00 0.01 -0.02 -0.10 -0.16 -0.24 -0.30 -0.36 -0.39 -0.35 -0.38 -0.41 -0.62 -0.76 -0.86 -0.83 -0.87 -1.11
4250 4216.97 -0.00 -0.00 -0.02 -0.07 -0.09 -0.18 -0.25 -0.40 -0.50 -0.54 -0.60 -0.52 -0.64 -0.77 -0.93 -1.10 -1.01 -1.01
4500 4466.84 -0.00 0.02 -0.01 -0.03 -0.02 -0.06 -0.07 -0.18 -0.27 -0.42 -0.57 -0.58 -0.56 -0.66 -0.77 -1.00 -1.12 -1.05
4750 4731.51 -0.00 0.01 -0.02 -0.08 -0.10 -0.17 -0.14 -0.18 -0.19 -0.32 -0.47 -0.66 -0.70 -0.71 -0.73 -0.94 -1.16 -1.18
5000 5011.87 -0.00 0.00 -0.05 -0.14 -0.20 -0.35 -0.44 -0.54 -0.53 -0.60 -0.63 -0.82 -1.01 -1.12 -1.09 -1.15 -1.41 -1.62
5300 5308.84 0.00 0.02 -0.01 -0.07 -0.10 -0.26 -0.39 -0.58 -0.71 -0.85 -0.87 -0.90 -1.07 -1.30 -1.40 -1.36 -1.43 -1.76
5600 5623.41 -0.00 0.02 -0.01 -0.04 -0.04 -0.10 -0.15 -0.29 -0.45 -0.71 -0.88 -0.94 -1.01 -1.16 -1.39 -1.51 -1.44 -1.54
6000 5956.62 -0.00 0.00 -0.03 -0.12 -0.17 -0.24 -0.27 -0.32 -0.38 -0.57 -0.80 -1.03 -1.20 -1.26 -1.41 -1.71 -1.77 -1.69
6300 6309.57 0.00 0.00 -0.05 -0.13 -0.20 -0.36 -0.45 -0.52 -0.59 -0.67 -0.82 -1.11 -1.40 -1.52 -1.56 -1.83 -2.15 -2.05
6700 6683.44 -0.00 0.01 -0.03 -0.09 -0.14 -0.30 -0.46 -0.67 -0.84 -0.88 -0.94 -1.05 -1.41 -1.78 -1.85 -1.87 -2.17 -2.47
7100 7079.46 -0.00 0.00 -0.05 -0.12 -0.15 -0.22 -0.25 -0.37 -0.56 -0.90 -1.12 -1.09 -1.17 -1.52 -1.96 -2.03 -2.00 -2.38
7500 7498.94 -0.00 0.00 -0.09 -0.21 -0.33 -0.58 -0.71 -0.82 -0.84 -0.96 -1.31 -1.66 -1.82 -1.81 -2.11 -2.57 -2.58 -2.68
8000 7943.28 -0.00 0.00 -0.03 -0.09 -0.15 -0.30 -0.50 -0.77 -1.08 -1.26 -1.30 -1.46 -1.91 -2.16 -2.21 -2.55 -2.90 -3.00
8500 8413.95 0.00 -0.01 -0.08 -0.18 -0.25 -0.37 -0.44 -0.54 -0.71 -1.11 -1.52 -1.63 -1.75 -2.09 -2.41 -2.56 -2.89 -3.30
9000 8912.51 0.00 -0.00 -0.08 -0.20 -0.32 -0.61 -0.82 -1.10 -1.22 -1.31 -1.56 -2.04 -2.42 -2.47 -2.78 -3.18 -3.29 -3.76
9500 9440.61 -0.00 -0.01 -0.12 -0.23 -0.26 -0.41 -0.46 -0.68 -0.98 -1.38 -1.66 -1.71 -2.12 -2.67 -2.78 -3.08 -3.45 -3.66
10000 10000.00 -0.00 0.01 -0.01 -0.08 -0.16 -0.49 -0.80 -1.13 -1.32 -1.44 -1.72 -2.25 -2.57 -2.74 -3.30 -3.49 -3.95 -4.12
10600 10592.50 -0.00 -0.02 -0.18 -0.44 -0.68 -0.93 -0.95 -1.09 -1.43 -1.89 -2.22 -2.35 -2.88 -3.31 -3.50 -4.13 -4.36 -4.64
11200 11220.20 0.00 -0.02 -0.08 -0.13 -0.05 -0.15 -0.48 -1.00 -1.21 -1.38 -1.78 -2.32 -2.55 -3.01 -3.50 -3.73 -4.36 -4.54
11800 11885.00 -0.00 0.02 0.01 -0.05 -0.28 -0.82 -1.17 -1.21 -1.45 -2.04 -2.28 -2.65 -3.25 -3.53 -4.03 -4.56 -5.04 -5.54
12500 12589.30 -0.00 -0.03 -0.23 -0.54 -0.87 -1.05 -0.98 -1.31 -1.90 -2.08 -2.56 -3.15 -3.36 -3.98 -4.44 -4.86 -5.42 -5.75
13200 13335.20 0.00 -0.02 -0.13 -0.24 -0.27 -0.44 -0.77 -1.35 -1.48 -1.92 -2.49 -2.74 -3.46 -3.76 -4.40 -4.85 -5.54 -5.99
14000 14125.40 -0.00 0.00 -0.08 -0.20 -0.42 -0.85 -1.20 -1.47 -1.81 -2.35 -2.64 -3.39 -3.63 -4.44 -4.84 -5.51 -6.06 -6.53
15000 14962.40 -0.00 -0.01 -0.11 -0.29 -0.54 -0.92 -1.15 -1.59 -2.04 -2.32 -3.03 -3.42 -4.20 -4.53 -5.20 -5.80 -6.52 -6.78
16000 15848.90 0.00 -0.03 -0.13 -0.37 -0.71 -1.08 -1.25 -1.79 -2.16 -2.70 -3.27 -3.73 -4.49 -5.07 -5.65 -6.31 -7.11 -7.72
17000 16788.00 0.00 0.00 -0.14 -0.36 -0.63 -0.97 -1.30 -1.94 -2.24 -2.92 -3.39 -4.12 -4.75 -5.44 -6.07 -6.66 -7.59 -8.07
18000 17782.80 0.00 -0.05 -0.25 -0.48 -0.71 -1.06 -1.54 -2.14 -2.40 -3.27 -3.67 -4.52 -5.26 -5.88 -6.58 -7.38 -8.19 -8.93
19000 18836.50 -0.00 -0.03 -0.25 -0.54 -0.75 -1.13 -1.71 -2.25 -2.67 -3.51 -4.10 -4.84 -5.69 -6.48 -7.12 -7.94 -8.95 -9.48
20000 19952.60 -0.00 -0.04 -0.25 -0.55 -0.85 -1.28 -1.80 -2.42 -2.97 -3.70 -4.54 -5.21 -6.21 -7.04 -7.80 -8.59 -9.59 -10.28

338
 Appendix

Nomi- Actual Angle in Degrees

nal Fre- Frequen-
quency cy [Hz] 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180
[Hz]
250 251.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
315 316.23 0.01 0.01 -0.01 0.00 0.01 -0.01 0.00 0.00 0.01 0.00 0.01 0.02 0.00 -0.02 0.00 0.00 -0.01 -0.03 -0.03
400 398.11 0.00 -0.01 -0.03 -0.02 0.00 -0.04 -0.01 -0.02 0.00 -0.01 0.01 0.03 0.00 -0.01 0.02 0.02 0.01 0.00 -0.01
500 501.19 -0.06 -0.05 -0.09 -0.08 -0.04 -0.09 -0.05 -0.07 -0.03 -0.05 -0.03 0.00 -0.03 -0.04 0.00 -0.01 -0.01 -0.01 -0.04
630 630.96 -0.13 -0.06 -0.17 -0.10 -0.08 -0.17 -0.14 -0.12 -0.08 -0.09 -0.05 -0.08 -0.10 -0.11 -0.09 -0.12 -0.13 -0.09 -0.22
800 794.33 -0.04 -0.04 -0.08 -0.08 -0.09 -0.09 -0.07 -0.09 -0.05 -0.05 -0.03 -0.04 -0.07 -0.06 -0.05 -0.03 -0.03 0.00 -0.06
1000 1000.00 0.03 -0.02 -0.06 -0.09 -0.06 -0.09 -0.06 -0.10 -0.09 -0.10 -0.07 -0.04 -0.04 -0.06 -0.01 0.00 0.02 0.04 0.00
1060 1059.25 0.03 0.00 -0.06 -0.09 -0.07 -0.10 -0.08 -0.12 -0.10 -0.12 -0.09 -0.06 -0.07 -0.10 -0.05 -0.06 -0.04 -0.02 -0.08
1120 1122.02 0.01 0.01 -0.06 -0.09 -0.10 -0.12 -0.10 -0.14 -0.12 -0.14 -0.11 -0.08 -0.09 -0.11 -0.06 -0.06 -0.04 -0.03 -0.06
1180 1188.50 -0.05 -0.02 -0.07 -0.11 -0.13 -0.15 -0.13 -0.17 -0.15 -0.17 -0.15 -0.11 -0.12 -0.13 -0.07 -0.06 -0.03 -0.02 -0.01
1250 1258.93 -0.14 -0.11 -0.14 -0.15 -0.19 -0.23 -0.20 -0.23 -0.21 -0.24 -0.23 -0.20 -0.21 -0.22 -0.19 -0.18 -0.13 -0.13 -0.11
1320 1333.52 -0.20 -0.21 -0.23 -0.20 -0.23 -0.31 -0.28 -0.31 -0.28 -0.32 -0.30 -0.28 -0.29 -0.29 -0.29 -0.27 -0.22 -0.22 -0.22
1400 1412.54 -0.21 -0.24 -0.27 -0.23 -0.23 -0.31 -0.29 -0.33 -0.30 -0.36 -0.32 -0.29 -0.28 -0.27 -0.26 -0.21 -0.15 -0.13 -0.16
1500 1496.24 -0.22 -0.22 -0.25 -0.23 -0.22 -0.27 -0.28 -0.33 -0.30 -0.35 -0.32 -0.27 -0.28 -0.29 -0.28 -0.23 -0.18 -0.15 -0.19
1600 1584.89 -0.26 -0.23 -0.23 -0.23 -0.23 -0.24 -0.27 -0.32 -0.29 -0.34 -0.31 -0.24 -0.26 -0.27 -0.25 -0.21 -0.18 -0.16 -0.19
1700 1678.80 -0.27 -0.22 -0.18 -0.20 -0.19 -0.19 -0.21 -0.27 -0.25 -0.31 -0.28 -0.22 -0.21 -0.22 -0.18 -0.11 -0.06 -0.03 -0.06
1800 1778.28 -0.23 -0.22 -0.16 -0.15 -0.16 -0.15 -0.15 -0.23 -0.21 -0.26 -0.26 -0.21 -0.17 -0.21 -0.21 -0.18 -0.11 -0.07 -0.09
1900 1883.65 -0.19 -0.22 -0.20 -0.12 -0.12 -0.15 -0.10 -0.19 -0.18 -0.21 -0.24 -0.19 -0.11 -0.12 -0.09 -0.04 0.05 0.07 0.10
2000 1995.26 -0.25 -0.23 -0.29 -0.17 -0.12 -0.23 -0.13 -0.18 -0.24 -0.21 -0.29 -0.24 -0.18 -0.19 -0.20 -0.18 -0.09 -0.04 0.01
2120 2113.49 -0.42 -0.38 -0.40 -0.37 -0.23 -0.33 -0.26 -0.25 -0.39 -0.35 -0.38 -0.36 -0.29 -0.26 -0.25 -0.18 -0.11 -0.04 -0.06
2240 2238.72 -0.48 -0.63 -0.54 -0.60 -0.48 -0.45 -0.47 -0.43 -0.53 -0.55 -0.55 -0.59 -0.48 -0.50 -0.52 -0.49 -0.42 -0.29 -0.33
2360 2371.37 -0.51 -0.65 -0.73 -0.67 -0.68 -0.53 -0.55 -0.56 -0.56 -0.67 -0.64 -0.67 -0.60 -0.55 -0.52 -0.50 -0.39 -0.29 -0.31
2500 2511.89 -0.55 -0.58 -0.77 -0.73 -0.74 -0.64 -0.57 -0.63 -0.59 -0.72 -0.69 -0.72 -0.65 -0.59 -0.58 -0.59 -0.50 -0.41 -0.42
2650 2660.73 -0.43 -0.55 -0.65 -0.76 -0.67 -0.65 -0.53 -0.59 -0.55 -0.72 -0.66 -0.71 -0.65 -0.60 -0.56 -0.56 -0.45 -0.29 -0.27
2800 2818.38 -0.46 -0.55 -0.65 -0.75 -0.71 -0.72 -0.55 -0.61 -0.59 -0.72 -0.72 -0.76 -0.74 -0.60 -0.53 -0.54 -0.43 -0.31 -0.32
3000 2985.38 -0.71 -0.70 -0.83 -0.90 -0.97 -0.88 -0.75 -0.72 -0.76 -0.81 -0.96 -0.92 -1.00 -0.83 -0.76 -0.82 -0.75 -0.60 -0.60
3150 3162.28 -0.84 -0.85 -0.88 -1.10 -1.15 -1.10 -1.01 -0.79 -0.88 -0.85 -1.12 -1.02 -1.20 -1.06 -0.95 -1.02 -0.93 -0.75 -0.69
3350 3349.65 -1.00 -0.80 -0.90 -1.05 -1.16 -1.29 -1.03 -0.91 -0.87 -0.87 -1.07 -1.04 -1.20 -1.11 -0.95 -0.99 -0.91 -0.71 -0.65
3550 3548.13 -0.97 -0.92 -0.78 -0.80 -1.12 -1.20 -1.09 -0.99 -0.78 -0.84 -0.91 -0.99 -1.10 -1.07 -0.81 -0.84 -0.81 -0.62 -0.57
3750 3758.37 -1.25 -1.10 -0.88 -0.94 -0.98 -1.24 -1.31 -1.10 -0.86 -0.93 -0.92 -1.11 -1.13 -1.16 -0.87 -0.85 -0.86 -0.68 -0.66
4000 3981.07 -1.33 -1.47 -1.39 -1.06 -1.10 -1.49 -1.52 -1.35 -1.19 -1.14 -1.11 -1.38 -1.33 -1.43 -1.12 -1.03 -1.09 -0.93 -0.90
4250 4216.97 -1.42 -1.71 -1.57 -1.34 -1.34 -1.48 -1.61 -1.69 -1.47 -1.25 -1.29 -1.49 -1.45 -1.60 -1.29 -1.18 -1.23 -1.07 -1.02
4500 4466.84 -1.09 -1.47 -1.81 -1.62 -1.20 -1.25 -1.63 -1.82 -1.47 -1.20 -1.31 -1.39 -1.45 -1.60 -1.35 -1.14 -1.19 -1.00 -0.94
4750 4731.51 -1.19 -1.42 -1.77 -1.77 -1.45 -1.43 -1.66 -1.76 -1.56 -1.43 -1.41 -1.30 -1.62 -1.66 -1.50 -1.19 -1.23 -1.03 -0.92

339
 Appendix

Nomi- Actual Angle in Degrees

nal Fre- Frequen-
quency cy [Hz] 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180
[Hz]
5000 5011.87 -1.54 -1.54 -1.97 -2.36 -2.08 -1.67 -1.68 -2.07 -2.18 -1.95 -1.68 -1.64 -2.04 -2.00 -1.93 -1.63 -1.64 -1.37 -1.24
5300 5308.84 -1.97 -1.84 -1.95 -2.45 -2.54 -2.13 -1.97 -2.36 -2.54 -2.17 -1.83 -1.93 -2.27 -2.18 -2.22 -1.86 -1.93 -1.71 -1.57
5600 5623.41 -1.90 -1.97 -1.84 -2.19 -2.63 -2.35 -1.91 -2.14 -2.42 -2.20 -1.96 -2.06 -2.26 -2.20 -2.25 -1.83 -1.86 -1.63 -1.50
6000 5956.62 -1.98 -2.40 -2.27 -2.24 -2.80 -2.94 -2.34 -2.24 -2.58 -2.60 -2.33 -2.27 -2.25 -2.50 -2.48 -2.11 -2.03 -1.76 -1.57
6300 6309.57 -1.97 -2.41 -2.66 -2.33 -2.52 -3.10 -2.82 -2.54 -2.81 -2.94 -2.57 -2.33 -2.46 -2.86 -2.80 -2.41 -2.36 -2.16 -1.95
6700 6683.44 -2.28 -2.33 -2.93 -3.03 -2.93 -3.43 -3.27 -2.75 -2.94 -3.25 -2.84 -2.45 -2.69 -3.26 -3.09 -2.84 -2.68 -2.44 -2.21
7100 7079.46 -2.70 -2.53 -2.80 -3.16 -2.90 -3.24 -3.69 -3.21 -3.11 -3.53 -3.16 -2.69 -2.90 -3.27 -3.15 -2.90 -2.66 -2.49 -2.22
7500 7498.94 -3.25 -3.15 -3.03 -3.66 -3.59 -3.61 -4.21 -3.73 -3.25 -3.83 -3.91 -3.34 -3.41 -3.62 -3.67 -3.40 -3.14 -3.03 -2.78
8000 7943.28 -3.29 -3.52 -3.42 -3.57 -4.16 -3.83 -4.18 -4.54 -3.75 -3.90 -4.18 -3.68 -3.61 -3.79 -4.03 -3.74 -3.41 -3.38 -3.11
8500 8413.95 -3.34 -3.64 -3.82 -3.66 -4.19 -4.16 -4.40 -4.77 -4.11 -4.11 -4.63 -4.00 -3.65 -3.89 -4.28 -4.03 -3.57 -3.59 -3.25
9000 8912.51 -4.04 -4.17 -4.41 -4.47 -4.43 -5.18 -4.56 -5.53 -5.13 -4.45 -5.00 -4.78 -4.29 -4.50 -4.97 -4.73 -4.11 -4.21 -3.86
9500 9440.61 -4.08 -4.32 -4.57 -4.55 -4.70 -5.00 -5.17 -5.01 -5.59 -4.88 -5.00 -4.98 -4.43 -4.61 -5.29 -5.01 -4.21 -4.25 -3.94
10000 10000.00 -4.41 -4.95 -5.13 -5.26 -5.09 -5.64 -5.74 -5.67 -6.17 -5.59 -5.62 -5.57 -4.81 -5.16 -5.96 -5.78 -4.92 -4.99 -4.66
10600 10592.50 -4.84 -5.66 -5.73 -5.89 -5.99 -5.85 -6.61 -6.17 -6.86 -6.35 -6.05 -6.69 -5.69 -5.79 -6.38 -6.32 -5.56 -5.62 -5.33
11200 11220.20 -5.08 -5.29 -5.96 -5.82 -6.22 -5.98 -6.40 -6.63 -6.54 -6.77 -6.08 -6.38 -6.07 -5.74 -6.19 -6.46 -5.65 -5.71 -5.42
11800 11885.00 -5.81 -6.22 -6.60 -6.69 -6.84 -7.06 -7.08 -7.77 -7.39 -7.95 -6.88 -7.35 -6.86 -6.32 -6.89 -7.28 -6.63 -6.49 -6.22
12500 12589.30 -6.24 -6.68 -7.02 -7.57 -7.29 -7.66 -7.45 -8.08 -7.93 -8.49 -8.13 -7.96 -7.81 -6.96 -7.43 -8.07 -7.42 -7.11 -6.92
13200 13335.20 -6.47 -6.80 -7.26 -7.56 -7.63 -8.13 -8.10 -8.29 -8.45 -8.48 -8.34 -7.99 -8.30 -7.15 -7.48 -8.50 -7.89 -7.43 -7.36
14000 14125.40 -7.09 -7.62 -7.91 -8.27 -8.65 -8.89 -9.22 -8.90 -9.58 -9.60 -9.77 -8.84 -9.40 -7.94 -8.18 -9.45 -8.78 -8.17 -8.20
15000 14962.40 -7.77 -8.15 -8.31 -8.80 -9.13 -9.52 -9.70 -9.36 -9.89 -9.60 -9.91 -8.94 -9.53 -8.95 -8.85 -10.27 -9.43 -8.58 -8.69
16000 15848.90 -8.14 -8.57 -9.46 -9.82 -9.82 -10.40 -10.67 -10.30 -10.88 -11.05 -11.53 -10.63 -10.30 -9.99 -9.98 -11.23 -10.39 -9.57 -9.70
17000 16788.00 -9.03 -9.53 -9.85 -10.29 -10.41 -11.12 -11.48 -11.22 -11.33 -11.86 -11.73 -11.51 -11.22 -10.86 -10.22 -11.69 -11.46 -10.42 -10.51
18000 17782.80 -9.76 -10.24 -10.80 -10.99 -11.37 -11.93 -12.53 -12.49 -12.07 -12.86 -12.64 -12.84 -11.76 -11.89 -10.91 -12.08 -12.48 -11.15 -11.39
19000 18836.50 -10.50 -11.05 -11.74 -12.45 -12.44 -12.86 -13.22 -13.33 -12.90 -13.90 -13.76 -13.71 -13.09 -13.30 -12.01 -12.61 -13.63 -12.05 -12.01
20000 19952.60 -11.34 -11.75 -12.63 -13.00 -13.60 -13.92 -14.22 -14.21 -14.52 -14.27 -15.01 -14.99 -13.71 -14.36 -12.72 -13.38 -15.20 -13.07 -12.92

The maximum measurement uncertainty of the data is with 95 % probability (k=2).

• 250 Hz to 1 kHz 0.3 dB
• 1 kHz to 4 kHz 0.5 dB
• 4 kHz to 8 kHz 1.0 dB
• 8 kHz to 12.5 kHz 1.5 dB

340
Appendix

341
 Appendix

Information for Calibration Hints for Performing the Electrical Measurements

Electrical input facility
Type Description (Refer IEC61672-1 paragraphs 5.1.15, 9.3.g)
• Integrating sound level meter type NTi Audio XL2-TA The capsule replacement NTI-K65-15 is used to insert electri-
cal signals to the preamplifier MA220. The device provides at
Standards one side a contact that corresponds to the center contact of
The XL2-TA Sound Level Meter has been certified in accor- the replaced microphone capsule, at the other side a BNC-
dance with the class 1 requirements of plug for the electrical signals. The impedance at the output
• ISO 61672-1 (2014 und 2003) of the device is 15 pF with a maximum deviation of ±1 pF.
• ISO 61672-2 (2014 und 2003) The electrical noise floor is measured by shorting the con-
• ISO 61260 (2014 und 2003) tacts of the BNC plug. Before the NTI-K65-15 can be mount-
• DIN 45657 (2014) ed to the preamplifier MA220, the microphone capsule must
• Welmec 7.2 «Software Guide» (2011) first be detached. The nominal sensitivity S of the capsule is
S = 42 mV/Pa. Measurements with the NTI-K65-15 therefore
require that the sensitivity in the calibration menu is manually
Approval Identification adjusted to S = 42 mV/Pa. The linear operating ranges accord-
The XL2-TA Sound Level Meter requires the approved firm- ing to IEC 61672 have been verified during the type approval
ware as follows: procedure.
• Germany: V4.71
• France: V4.21 Certified Calibrator
• Austria: V4.21 The following sound level calibrators are certified with the
• Switzerland: V4.11 XL2-TA with a 114 dB, 1 kHz reference signal.
• Larson Davis CAL200
• B&K 4231
• Norsonic Nor-1251, Nor-1256
• Microtech Gefell 4010

342
 Appendix

Compulsory Calibrated Applications

The following acoustic measurements have been verified by
German PTB during the type approval process:

Instantaneous sound pressure levels:

Time averaged sound pressure levels:
• LAF
A-weighted sound pressure level with time weighting FAST • LCpeak
Peak value of the C-weighted sound level
• LAS
A-weighted sound pressure level with time weighting SLOW • LAeq
A-weighted average level
• LCF
C-weighted sound pressure level with time weighting FAST • LAE
A-weighted sound exposure level
• LCS
C-weighted sound pressure level with time weighting SLOW • LAFT3eq
A-weighted clock-impulse maximum level with time weight-
• LZF
ing FAST for a clock-impulse duration of 3 seconds
unweighted sound pressure level with time weighting FAST
• LAFT5eq
• LZS
A-weighted clock-impulse maximum level with time weight-
unweighted sound pressure level with time weighting SLOW
ing FAST for a clock-impulse duration of 5 seconds
• LAI
A-weighted sound pressure level with time weighting
IMPULSE

343
08.23