Speaker System Design Points
Achieving consistent sound pressure level at the listening plane (the average height of the listeners ears) is an important goal in speaker system design.
The following points should be kept in mind.
n Ceiling Speakers
Example
Ceiling
It is important to note that the nominal coverage angle listed in ceiling
speaker specifications is not the same as the speakers actual effective
coverage angle. SPL at the nominal coverage angle is 6dB lower than
the on-axis SPL, measured at a constant distance from the speaker. The
effective coverage angle is defined as the angle at which the SPL is 6dB
lower than the on-axis SPL at the listening plane. The effective coverage angle is usually about 70~80% of the nominal coverage angle.
CISSCA calculations are based on effective coverage angles.
- 6dB
SPL:
Point 1 < Point 2 (Point 1 is even further off axis)
Distance attenuation:
Point 1 < Point 2 (Point 1 is closer to the speaker)
The net result is that the SPL at Point 1 is similar to the SPL at Point 2,
and therefore also similar to the SPL at Point 3.
90
120: Nominal coverage angle
Commercial lnstallation Solutions Speaker Calculator
- 6dB
90: Effective coverage angle
-12dB
n Surface Mount Speakers
Uniform sound pressure level can easily be achieved throughout the
listening plane with speakers that include horns by aligning the speakers axis with the head of the most distant target (listener). This works
because of the relationship between distance and coverage angle.
When the perpendicular axis is aligned with the last row, the natural
distance attenuation at the last row and the off-axis attenuation at
closer rows tend to result in uniform SPL distribution. CISSCA allows
fine adjustment of surface mount speaker tilt angle for maximum
system design flexibility.
Speaker
120
Reference Point (0dB)
-6dB
- 6dB
-12dB
SPL:
Point 2 < Point 3 (Point 2 is off axis)
Distance attenuation:
Point 2 < Point 3 (Point 2 is closer to the speaker)
Distance attenuation and off-axis loss cancel out
so that similar SPL is achieved at all three points.
Speaker
Axis
Essentially uniform sound pressure level
Speaker Axis Angle
P.O.BOX1,HamamatsuJapan
www.yamahaproaudio.com
*All specifications are subject to change without notice.
*All trademarks and registered trademarks are property of
their respective owners.
LPA639 Printed in Japan
This document is printed
with Vegetable Oil Ink.
4 Steps to an Ideal Speaker
Estimate for Your Project
4 Steps to an Ideal Speaker Estimate for Your Project
Commercial Installation Solutions Speaker Calculator (CISSCA) is a software application that quickly calculates the number
of speakers required for optimum performance in a room specified by the user, plus the effective sound pressure level of
the system. The user specifies the room size, type of speakers to be used, and speaker layout.
CEILING SPEAKER SURFACE MOUNT
SPEAKER
SUBWOOFER
A fast, easy way to estimate the number of speakers required for any project.
Easy setup and operation.
n Report output function provides convenient documentation for system proposals.
n
n
Supported Speakers
*Not available in some regions.
VXC Series
VXS Series
VS Series
NS-AW Series*
NS-IC Series*
S Series*
STEP2
STEP3
Specify the target sound pressure level and the types of speakers to be
used. CISSCA V2 allows surface mount speakers and subwoofers to be
selected in addition to ceiling speakers.
Specify a speaker system layout. An estimate of the number of ceiling
speakers required for the project will be provided, plus surface mount
speakers and subwoofers that can be positioned as required.
PAGE1
PAGE2
PAGE3
HOME
STEP1
STEP4
REPORT
Display language (English or Japanese), units (meters or inches), and
SPL display (on or off) can be selected via the OPTIONS button in the
HOME screen.
Specify the dimensions of the room to be used for the project, and the
height of the listening plane.
Check the difference between the effective sound pressure level of the
estimated system and the target sound pressure level entered in STEP 2.
Click the REPORT button to output the results in report form.
The report output function included with this application (pdf format) is a
convenient way to generate support documentation for system proposals.
