[sdiy] FM Synth Designs

Duane R Balvage dbalvage at ptdcs2.ra.intel.com
Tue Aug 13 18:00:24 CEST 2002


Hi Colin -
> My understanding was that the DX7 implemented 'multiplication' to vary the
> amplitude of it's operators by adding two sine waves together with a phase
> difference proportional to the required amplitude, instead of acutally
> multiplying the wave data by the amplitude value.
> This would mean changing the waveforms wasn't viable.
> Later units with a choice of waveforms used hardware multiplication.
> Could be wrong...

Actually, the waveform isn't an actual sine... it's the LOG of a sine.
That way, instead of computationally expensive multiplication, it used addition.

(that whole sum of LOGs = multiplication thing... :) )

			-Duane

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