Sound Synthesis; Dc0 1 - Korg POLY-800 Owner's Manual

3. SOUND SYNTHESIS

A synthesiser is a set of modules or "building blocks" that
can be used together to create many different types of sounds.
In all synthesizers. there are three basic types of modules:
sound SOURCES, sound MODIFIERS, and sound
CONTROLLERS.
The basic sound SOURCES used in the Poiy-600 are eight
Digital Controlled Oscillators (DCOs). The DCOs produce the
actual pitches, and the selected DC0 WAVEFORM (and selec-
lion of 2'. 4' Harmonics etc.) has a large effect on the tonal
quality (timbre) of the sound. A NOISE source is also provided.
The sound MODIFIERS for the Poly-800 are the Voltage Con-
trolled Amplifiers (VCAs), the Voltage Controlled Filter (VCF).
and the Stereo Chorus. Sound modifiers take the basic sound
produced by the sound sources and shape or "line tune" the
sound into its final form - what you actually hear.
The VCF modifies the blend of overtones (and
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brightness) in the sound.
The VCAS control the changes in volume ievel which
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provide individual note articulation how each note
attacks, decays. etc.
The Stereo Chorus provides extra warmth and
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"thickness" for almost any sound.
The sound CONTROLLERS don't produce or modify any
sounds directly - they tell the sources and modifiers what
to do. Controllers in the Poly-800 include the Keyboard and
Key Assigner, advanced 6.stage Envelope Generators.
Modulation Generator, Programmer, Joystick and MIDI
interface
Without controllers, there would be no way of coordinating
the different modules in the synthesizer to produce useful
sounds.
MIDI (Musical Instrument Digital Interface) is actually an EX-
TERNAL Controller, which allows different instruments and
equipment to be coordinated for a wide range of new
possibilities.
Each of the sources, modifiers and controllers described
above have several PARAMETERS (variable settings such as
Waveform, Cutoff, Attack Time, etc.).
A "Prcgram".is the particular collection of Parameter set-
tings that results in a specific desired sound.
On many synthesizers. knobs must be turned to adjust the
Parameters. and it's hard to tell what the exact values are -
especially when you're editing an existing program. the most
common way of creating new programs.
On the Poly-800. each parameter and its value are express.
ed by a pair of numbers:
* The PARAMETER NUMBER (middle two digits of the
six digit DISPLAY) identifies a particular Parameter,
which is like a single control knob on other synthesizers
(Filter Cutoff, for example, is Parameter '-:
Poly-800).
The VALUE (righthand two digits) is like the current set-
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ting of that control knob, or Parameter (e.g.. Filter Cutoff
can have a Value between z and 32 ).
The eight Number Buttons (also used for Program Selec-
tion). UP and DOWN buttons and large LED Display make
it easy to adjust and DOWN button and LED Display make
it easy to adjust each program parameter precisely for the
exact desired result. T change any aspect of a programm-
O
ed sound, you simply:
select a Parameter Number
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* adjust its Value. using the UP and DOWN buttons
* repeat above to change other Parameters. as needed
Further information is given in the section on "Creating
Sounds':
of parameter
Name
Parameter number
SOUND SYNTHESIS
the