Comparison To The Organ; Theory Of The Synthesizer; Vco (Voltage Controlled B) Vcf - Roland SH-1000 Instruction Manual

1.
Comparison
to
the
Organ
2.
Theory
of
the
Synthesizer
A
synthesizer
is
not an
organ.
The
usual electronic
organ
is
not
able to freely
modify sound
envelopes characterized
by "Attack",
"Decay" and "Sustain"
etc. all
of
which
play
an important
role
in
the
quality of musical sounds. Here,
"Attack" means
the
rising
of
the
sound, "Decay", the diminishing of the sound and
"Sustain",
the maintaining of the sound, while
"Envelope"
is
defined by
the
curve
of
these characteristic
elements.
The
Synthesizer,
however, can modify
these
elements
to
change
envelope
characteristics
and
thus
modify volume and
tone
to-
synthesize
many
sounds which
are unlike
any which can be
produced by conventional instruments,
in
addition
to
sounds
which
are
exactly
like
those of conventional instruments.
Thus, the Synthesizer has the inherent capability of extending
the
range of musical conception through production of unique
new
sounds.
The
Voice Generator, which
generates electronic
signals
that play
an important
role
in all
electronic musical instruments,
is
composed
of the
VCO
"Voltage Controlled
Oscillator",
and
its
musical
interval
is
controlled by
the voltage
coming from
the
keyboard
switch.
As
the
wave form
of the
music sound produced
by
the
VCO
has
many
harmonics,
the desired
tone
is
produced
through
a
VCF
or "Voltage Controlled
Filter".
The
function of
the
Filter
is
also
dependent on
the voltage.
The
signal
through
the
VCF
is
modified with
regard to the
rising,
falling or the
maintaining of sound by
the function of
the
VCA
"Voltage Controlled
Amplifier".
Consequently,
the
VCO,
VCF
and
VCA
are
the crux of Syn-
thesizer operation.
There
are
included various kinds of voltage generators
to
modify
these three
circuits.
Firstly,
when
a
key
is
depressed, voltage
is
supplied
to the
ADSK
until
release
of key. This voltage
is
the basis
of
the various
envelopes.