SYNTHESIS
Synthesis
has
traditionally
been
something
of
a
geeky
area
of
music
technology
it
is
potentially
a
complex
area
of
the
subject
as
it
examines
in
a
detailed
manner
exactly
how
electronic
instruments
produce
particular
sounds.
To
synthesise
something
is
to
create
an
end
product
the
implication
is
that
the
end
product
is
in
some
way
artificial
and
not
organic.
The
sounds
that
synths
produce
are
usually
not
found
in
the
natural
world,
and
this
is
probably
their
most
interesting
feature.
To
understand
how
a
synth
generates
a
sound
it
is
useful
to
understand
what
elements
make
up
any
sound.
We
hear
sounds
because
the
ear
detects
vibrations
of
air
within
the
ear,
and
our
brain
detects
this
as
a
particular
quality
of
sound,
and
is
able
to
distinguish
accurately
between
a
huge
number
of
sounds.
Most
what
follows
refers
to
analogue
or
virtual-analogue
synths
(digital
hardware
and
software
synths,
which
allow
you
to
shape
sounds
like
an
analogue
synth).
Any
sound
always
has
three
main
elements:
Pitch
Tone
Volume
We
understand
and
recognise
different
sounds
by
the
proportion
of
these
three
qualities,
and
how
these
proportions
change
throughout
the
duration
of
the
sound.
Pitch
The
ear
detects
pitch
by
the
number
of
vibrations
of
air
per
second
within
the
ear.
A
high
note
has
many
vibrations,
and
a
low
note
has
fewer
vibrations
these
are
detected
in
Hertz
(Hz):
for
example
a
frequency
of
50
Hz
means
that
there
are
50
vibrations
per
second.
The
range
of
a
human
with
excellent
hearing
is
typically
within
the
range
20
Hz-20
kHz.
Pitch
is
sometimes
called
frequency
because
of
the
frequency
of
sound
vibrations
per
second
within
the
sound
wave.
A
higher
sound
wave
will
have
its
peaks
closer
together
than
a
lower
note
hence
they
occur
with
greater
FREQUENCY.
Tone
Musical
sounds
consist
of
a
number
of
different
related
pitches
sounding
simultaneously.
The
loudest
part
of
a
sound
(and
the
one
that
enables
us
to
perceive
the
pitch
of
the
note)
is
called
the
FUNDAMENTAL
pitch.
In
addition
to
the
fundamental
pitch,
there
are
other
related
pitches
called
HARMONICS
it
is
the
relative
loudness
of
these
harmonics
which
allows
us
to
distinguish
various
qualities
of
sound.
For
example,
when
we
hear
a
flute
and
a
trumpet
play
the
same
note
we
can
tell
which
instrument
is
which
it
is
the
harmonics
present
within
each
sound
that
allows
us
to
distinguish
between
the
two
instruments.
Page 1 of 3
SYNTHESIS
Volume
The
loudness
of
a
sound
is
sometimes
called
its
amplitude,
and
relates
to
how
large
the
sound
waves
are.
The
wave
forms
of
the
same
note
played
loud
and
soft
would
have
the
peaks
the
same
distance
apart,
but
the
louder
note
would
have
taller
peaks.
A
synthesiser
functions
by
taking
these
three
elements,
and
allowing
the
user
to
control
them
and
other
parameters
to
create
the
desired
sound.
Typically
a
sound
will
follow
a
path
similar
to
this:
Oscillators
Filter
Envelope
Generator
Oscillators
The
oscillator
is
the
main
sound
source
in
that
it
generates
the,
basic
waveform
that
will
make
up
your
patch
(sound).
Depending
on
the
quality
of
the
synth,
an
oscillator
can
produce
five
or
six
basic
waveforms
some
synths
have
a
number
of
oscillators
to
widen
your
sonic
arsenal.
Filters
These
shape
your
raw
sound.
They
are
used
to
filter
out
certain
frequencies
within
the
spectrum.
Filters
can
be
used
to
change
preset
sounds,
or
used
to
create
sweep
effects:
this
is
controlled
by
two
filter
controls
frequency
and
resolution.
Envelope
Generator
This
part
of
the
synth
controls
the
four
main
parameters
of
a
sound
envelope.
The
envelope
of
the
sound
is
the
last
stage
in
determining
the
character
of
the
sound,
and
is
usually
called
an
ADSR
envelope
this
refers
to
the
four
volume
stages
of
a
sound:
Attack
the
time
it
takes
for
a
sound
to
reach
its
loudest
point;
Decay
the
time
it
takes
for
the
sound
to
move
to
the
sustain
level,
and
begins
immediately
after
the
attack.
During
this
time
the
sound
is
usually
quieter
than
the
attack;
Sustain
this
is
the
level
at
which
the
sound
settles
down
to
for
most
of
the
duration
of
that
sound;
Release
the
time
taken
for
the
note
to
die
away
when
the
synth
key
is
released.
A
short
release
time
means
that
the
note
will
end
immediately
the
key
is
released.
A
long
release
would
mean
that
you
would
hear
the
note
die
away
to
nothing.
Page 2 of 3
SYNTHESIS
Waveforms
As
I
mentioned
earlier,
a
synth
can
produce
a
number
of
basic
waveforms,
which
have
varying
harmonic
make-up,
and
therefore
different
sound
qualities.
Sine
waves
are
the
simplest
types
of
sound,
because
they
have
no
harmonics
just
a
fundamental
pitch.
For
this
reason
their
sound
is
extremely
pure
and
they
are
often
used
as
test
tones
or
for
tuning
instruments.
Sawtooth
waves
also
called
saw
waves,
have
a
very
strong,
clear,
buzzing
sound.
A
sawtooth
wave
can
be
made
by
adding
a
series
of
sine
waves
at
different
frequencies
and
volume
levels.
The
frequency
of
the
first,
loudest
sine
wave
is
what
we
hear
as
the
frequency
of
the
resulting
sawtooth.
This
is
called
the
fundamental
frequency.
Each
of
the
other,
progressively
quieter,
sine
waves
that
make
up
a
sawtooth
have
frequencies
which
are
integer
multiples
of
the
fundamental
frequency.
These
frequencies
are
called
harmonics.
Square
waves
have
a
rich
sound
that's
not
quite
as
buzzy
as
a
sawtooth
wave,
but
not
as
pure
as
a
sine.
Old
Nintendo
game
soundtracks
were
made
almost
exclusively
from
square
waves.
Like
sawtooth
waves,
square
waves
can
be
generated
by
adding
a
series
of
sine
waves
with
decreasing
volume.
However,
the
square
wave
contains
only
the
odd
numbered
harmonics.
Triangle
waves
sound
like
something
between
a
sine
wave
and
a
square
wave.
Like
square
waves,
they
contain
only
the
odd
harmonics
of
the
fundamental
frequency.
They
differ
from
square
waves
because
the
volume
of
each
added
harmonic
drops
more
quickly.
Below
is
a
diagram
with
the
visual
descriptions
of
each
of
the
above
waveforms,
these
will
look
very
similar
when
you
are
working
with
Logic
synthsas
such
do
get
to
know
and
recognize
the
symbols..
Page 3 of 3
