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FLUTE
VIOLIN
TRUMPET
HARPSICHORD
XYLOHPONE
ENVELOPE
WAVEFORM
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ADSR
SETTING
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VCA CONTROL
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VCF CONTROL
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SYNTHESIS
The
synthesis of
sound
is
an
art
in itself.
The
most
important
ingredients
to
its
mastery
are
practice
and
patience.
In
this
case,
we mean
practice
in
the sense of familiarity
with
the con-
trols
and
their effects
on
the
sound,
as
well
as
keyboard
playing technique.
When
setting
the
synthesizer so
as
to create
sounds, always
try
to
be aware
of
why
the controls
affect
the
sound
the
way
they do.
Perhaps the
best
approach
to synthesis
in
general
is
the imitation of
sounds
you
know.
Even
if
you
feel
that
you
may
never
want
to use these
types
of
sounds
in
the
music you
play,
the
practice
involved
in
imitating
sounds forms
an
excellent
foundation
on which
to
build.
If
you
can imitate
known
sounds, then
you
are well
on
the
road
to
being
able
to imitate
any sound you
might imagine
in
your
head.
An
imitative
sound
can
also
form
the
starting
point
for non-imitative
or
purely
electronic
sounds.
The
ability
to
imitate
sounds
also gives
you
a
strong
insight into
the
analysis
of
acoustics.
These
insights are
essen-
tial
to
producing sounds of imaginary
instruments;
sounds
which do
not
exist
in
the
real
world
but
seem
as
if
they should
exist
somewhere.
The
following
gives
some
hints
on
how
to
approach
the actual synthesis of specific
sounds.
HOW
TO
SYNTHESIZE
SOUNDS
The
three
qualities
of
sound
are:
pitch,
tone
color,
and
loudness. Pitch
and
loudness
usually
present
little
problem
in
synthesis.
If
we
want
to
synthesize a piccolo or a pizzicato
string bass,
it
is
extremely
simple to decide
and
set
the correct
pitch range,
and by
repeatedly depressing
a
key
on
the
keyboard
while adjusting the envelope
generator
controls,
we
can
easily arrive at
the
cor-
rect
envelope
for these
sounds.
Tone
color
is
a
different
matter,
however, and
often
requires
much
trial
and
error to get
the
desired
sound.
This
is
where
practice
and
patience
will
pay
off.
PITCH
First
set
the
sound
source.
The SH-7
has
two
basic
sound
sources: the
VCO's
and
the Noise
Genera-
tor.
The
Noise Generator
is
used
for
synthesizing
sounds
of
indefinite pitch
such
as
wind, thunder,
cymbals,
etc.,
or
for
adding
this
quality
to
pitched sounds, such
as
drums.
The VCO's
are
used
for
pitched sounds. Set the
RANGE
and,
for
the
time
being,
use
any
waveform
output.
LOUDNESS
Next,
set
the
Envelope
Generator. For
this,
the
Basic
Patch
shown on
the opposite page can
be
used.
While
repeatedly depressing a key,
set
the
Envelope Generator
controls so that the
output
sound
takes
on
the
approximate
loudness
pattern
of the desired
sound.
The
drawing above shows
some
sample envelopes and Envelope Generator
settings.
TONE
COLOR
Tone
color
should be considered
after pitch
and
loudness because
it is
often very strongly affected
by
pitch
and
loudness.
The
SH-7
provides
five
methods
for controlling
tone
color of synthesized
sound
(excluding the use of an external
sound
source):
VCO's,
Noise Generator,
Ring Modulator,
High
Pass
Filter
(HPF),
and
Voltage Controlled
Filter
(VCF).
The
VCO
represents the
prime
source of
tone
color
for
pitched
sounds
since
the
output
waveform
which
is
selected
will
determine
the
tone
colors available for synthesizing
sound.
The
Noise Generator
represents the
prime
source
of
tone
color for
sounds
of
indefinite pitch.
The
two
filters
are
used
to
remove unwanted harmon-
ics
from
the
sound
source.
The
Ring Modulator
is
normally
the only portion of the synthesizer
which
is
used to
add harmonics which
are
not
present
in
the
original
waveform.
Using
two
VCO
inputs,
the
Ring
Modulator
produces
metallic clanging
sounds.
To
set
tone
color,
start
by
deciding the
sound
source
waveform;
the
drawing on
the
bottom
of
the
opposite
page
gives
some
suggestions
for
various
types of
sound.
If
in
doubt,
try
a
sawtooth
wave
to begin
with
since the
sawtooth
wave
is
usually a
little
more
common
than the
others.
Next,
set
the
filters.
For
sustaining
type sounds
(or
sounds
in
which
the
Envelope Generator
SUSTAIN
control
is
at
any
position
other than
"0"), depress
a
key and
adjust the
filter
controls
so
as
to
produce
a
tone
color near the desired
tone
color.
Many
instruments
produce
a
tone
color
which
is
dynamic
in
quality,
or
in
other
words, the tone color changes during the produc-
tion
of each
note.
This
is
particularly
so
with
brass
instruments
and plucked
string
sounds. This
can be imitated
by
controlling the
VCF
cutoff
point with the
Envelope Generator. While
repeat-
edly depressing
a
key on
the
keyboard,
little
by
little
raise
the
VCF
ENV-1
control.
Each time
you
raise this
control,
lower
the
VCF CUTOFF
FREQ
control
slightly
to
compensate.
The
tone
color of
an instrument
will
also
often
be
slightly
different for different pitch ranges.
This
effect
can
be produced
by
using the
keyboard
control
voltage to control
the
VCF
cutoff point.
First,
readjust
your sound
so that
lower keys
on
the
keyboard produce
the
tone
coloring of the
lower
pitches.
Normally,
this
tone
coloring
is
darker
than the higher
pitches.
Next,
try
playing pitches
higher
on
the keyboard. Raise the
VCF KYBD/
PEDAL
control (switch
at
KYBD)
to brighten
these
upper
pitches.
Now,
try
pitches at various
places
on
the
keyboard and touch
up
the
VCF
controls so that
you
get
the desired
effect.
Don't
forget that using
the
VCO
Pulse
Width
Modulation
is
also
another
source of
tone
color
which
changes.
OTHER
DETAILS
OF SOUND
Once
the basic
sound
is
set,
you
are
ready to
add
the extra
details
to
the
sound, such
as
portamento,
vibrato,
etc.
During
this
process,
you
will
also
probably
want
to
touch
up
the previously
set
controls to
make
your sound
perfect.
22
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