Korg opsix, Owner'S Manual, Page: 7 / 105

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2. About the sound generator of the opsix
The principles of FM sound generation were discovered and established by Dr. John Chowning at
Stanford University in the 1970s, when he was experimenting with vibrato. FM sound generation was
later packaged into an LSI chip and put into practical use by Yamaha Corporation. From the
beginning of the 1980s, FM tone generation was used as an internal sound source on the DX series,
personal computers, game machines and cellphones.
Operator (modulator, carrier)
The FM (Frequency Modulation) sound generator is based on syn-
thesis elements called “Operators.” Operators are modulated using
simple input waveforms (WAVE) such as sine waves, outputting
sounds with complex harmonics. Operators can act as either a
modulator or a carrier. The output sound from a modulator feeds
into another Operator and modifies that Operator’s output.
Carriers receive the output sound from modulators and output the
modulated result as audio.
Algorithms
In the FM sound generator, the combination of the roles and
connections of the Operators is called an “algorithm.” Selecting an
algorithm is a good starting point for creating sound. The opsix
sound generator includes six Operators, and more than 40 preset
algorithms are provided. You can use the user algorithm function
to create new combinations as well.
Operator modes
Although the basis of the opsix is the FM sound generator, you
can change the Operator mode to perform different kinds of
modulation besides FM. The combination of ring modulator, filter,
and wavefolder makes it possible to create new kinds of sounds
that surpass the range of typical FM sounds.
An Operator includes an input, an output and an oscillator. The
carrier’s Operator mode determines how the oscillator is modulat-
ed by the input of the modulator. This modulation gives the sound
its character. To add to the FM, Ring Mod, Filter, Filter FM and Wave Folder Operator modes, the
opsix features Mute and Bypass modes that are useful when editing.
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Audio Ouptut
What happens when
modulators modulate
the carriers
Algorithm example
(preset algorithm 1)
Modulator output
Basic carrier waveform
Carrier output
Carriers
Modulators