Roland SH-201 Manual page 4

The Basic Structure of a Synthesizer
Chapter
2
A typical synthesizer will have a signal flow-chart
similar to the one pictured below.
To start, let's understand the fundamentals.
OSC 1
PITCH
ENV
OSC 2
OSC
( ➝ P. 9 )
Oscillator
This is the basis of the sound, where the waveform and pitch are selected. It is indeed
the heart and soul of a synthesizer. On analog synthesizers, it is called the VCO
a sound generator capable of changing frequency through changes in voltage. The SH-201
has two oscillators (OSC1 and OSC2). It's like having two synthesizers in one.
FILTER
( ➝ P. 11 )
This is where the sound signal generated from the OSC is processed through the emphasis
and rejection of a selected frequency range. On analog synthesizers, it is called the VCF
A VCF is used to continuously change the characteristics of a filter (cutoff frequency)
through changes in voltage. The SH-201 houses three separate filters, each designed
for a specific purpose.
LPF
Low Pass Filter
level
partials which are cut
frequency
5
LFO 1
MIX/
FILTER AMP
MOD
FILTER AMP
LFO 2
ENV ENV
HPF BPF
High Pass Filter Band Pass Filter
level
level
partials which are cut
partials which are cut
frequency
AMP
( ➝ P. 13 )
Sound generated in OSC and processed through the FILTER is amplified here.
On analog synthesizers, it is called the VCA
the volume (level) of sound signal through changes in voltage.
LFO
Audio signals
Low Frequency Oscillator
Control signals
This is a sound generator capable of producing low frequencies. On analog
synthesizers, it is also called the LFO
AMP individually as it adds modulation. LFO is a "must have" for producing
synthesizer-like effects.
Examples of LFO
applied to OSC
LFO
applied to FILTER
applied to AMP
ENV
Envelope Generator
An envelope generator controls the initiation and termination of sounds.
On analog synthesizers, it is also called ENV
the keyboard, ENV affects the volume and timbre on OSC, FILTER, and AMP
individually as it processes its time-varied elements.
Examples of ENV
applied to OSC
ENV
applied to FILTER
applied to AMP
(*1) . A VCO is
PITCH ENV
pitch
A
Key-on
(*2)
.
Analog Synthesizer
Once considered relics, analog synthesizers are attracting attention once again.
The simple and easy-to-understand OSC ➝ FILTER ➝ AMP structure enables real-time control
to achieve dynamic sound variation. Moving knobs and faders to create your own unique sound can
be a very exciting experience indeed. The SH-201 is recommended not only for keyboardists,
but for any artist or producer who desires a new outlet for creativity expression.
frequency
(*3)
. The VCA is used to change
( ➝ P. 15 )
(*4) . The LFO affects the OSC, FILTER, and
Vibrato
WahWah (Growl)
Tremolo
( ➝ P. 10, 12, 13 )
(*5)
. Every time you play
Pitch becomes higher or lower
Sound becomes brighter or darker
Sound becomes louder or softer
FILTER ENV
cutoff frequency
Key-off
DEPTH
S
DEPTH
time
time
D A D R
Key-on
(*1) Voltage Controlled Oscillator (*2) Voltage Controlled Flter (*3) Voltage Controlled Amplifier
Chapter
2
AMP ENV
volume
Key-off
S
time
A D R
Key-on
(*4) Low Frequency Oscillator (*5) Envelope Generator
6