Yamaha CS-5 Owner's Manual page 4

WHAT
IS
A SYNTHESIZER
Unlike other musical instruments,
the
synthesizer has
no
fixed
sound
of
its
own. Thus,
before playing
it, it is
necessary
to
shape the sounds.
But with
the synthesizer
you
will
be able to create,
with your
own
liands
and by
synthesizing sounds,
a
new
type of sound
that
can never
be
made
by any
other musical instrument.
•
THE THREE ELEMENTS
OF
SOUND
How
does
a
synthesizer
make
sounds? Before
explaining the principle of the synthesizer,
let
us
consider
what
kind of properties
sound
has.
Sound produced by
musical instruments such
as
the
piano or
the guitar
has
a
certain pitch,
according
to
the
key
or
string
used.
It is
possible to
change
the
pitch
by
changing the length of the vibrating portion
of
the
string.
In
this
case, the
string's
nuinber of
vibrations per
second
also
changes.
The
slower
the
string vibrates,
the
lower
the
pitcii
becomes.
In
this
way,
it is
possible to express the difference
in
pitch
by
the
number
of vibrations (frequency).
PITCHES
30rSS
$(?UJO(i
wwwv
However, between
the
sound of
a
piano and
that
of
a guitar there
is
a
difference
in
tone even
when
both sounds
are of the
same
pitch:
no one
will mis-
take the
sound of
the
piano
for that of the
guitar.
This
is
because
there
is
a difference
in
the
way
the
strings vibrate
(tlie
vibration
waveform
),
due
to the
difference
in
the
arrangement
by which
the
sounds
are generated,
and because of
the difference
in
the
shape
and
size
of the musical instruments.
TONES
jDifferetlca (n -tones
means
PIOMO
Furthermore, even
when
both
the pitch
and tone
quality
are
the
same
there
can be
a
difference
in
sound, such
as
when
the
same key of
the
piano
is
hit
in
a forcible or
a
gentle
manner.
It is
easy to discern
the
two sounds trom each
other because of the
magnitude (volume)
of the sound. This
is
because
a
difference
will
be produced
in
the
size
and amplitude
of
the string's vibrations,
due
to
the intensity with
which
it
has been
struck.
In this
way, sounds produced by
musical
instru-
ments
have such elements
as pitch,
tone and volume,
whose
differences
add
to the
sound's
characteristics.
These elements
are referred to as
"the
three elements
of sound", which
may
also be considered
as the
difference
in
frequency,
waveform and
amplitude.
•
TEMPORAL CHANGE
IN
SOUNDS
However,
the elements which
render sounds with
certain
ciiaractcristics are
not confined
to these
three.
Taking
the
piano
for
example,
the
volume
will
reach
maximum
the instant the
key
is
hit,
then
will
decrease graduahy.
When
the finger
is
released
from
the
keyboard,
the
sound
will
fade out. In the case of
the
organ, the action of
depressing the
key
will
cause
the
volume
to
rise
to a certain
level,
which
will
be
retanicd for the
duration the
keyboard
is
depressed.
The
sound
will
fade
away when
the finger
is
released
from
the key.
Ktr ON
In
such musical instruments
as
the trumpet,
for
example,
the
harmonic spectrum changes together
with
the
change
in
volume.
The
tone changes
too,
along with
the
passage of
time.
Thus,
the
sounds of musical instruments
undergo
delicate
changes from
the time the
sound
is
generated
to
the time
it
fades
away. These temporal changes
are
known
as an
"envelope."
HARMOMICS
What must we
do
in
order
to
produce
electrical
sounds
that
have
the
above
mentioned
three elements
of sound, these
are pitch,
tone
and volume, and which
vary
with time (have an envelope)? Before going
into
the matter,
let
us
view sound
again
from
a
different
angle
As
regards the vibration
waveforms by which
the
tone
is
determined,
it is
known
that
any
given
wave-
form
can be considered
as
consisting of
a
certain
number
of
sine
waves.
!n
other words,
all
waveforms
can be produced by combining
a large
number
of
sine
waves.
For example,
let
us overlap over
a single
sine
wave waveforms
having an
integral
multiple
o