[sdiy] FM Synth Designs

[Colin Fraser]

----- Original Message -----
From: "Batz Goodfortune" <batzman at all-electric.com>
To: "ben" <benj at iinet.net.au>; <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, August 13, 2002 12:48 PM
Subject: Re: [sdiy] FM Synth Designs


> There is no outboard ROM chip if that's what you were thinking. Had there
> have been I would probably have been the first to throw in a rotary switch
> and be able to select between a bank of different wave forms. The
> wavetable/ROM is in the OPs chip. This chip is responsible for the time
> slicing and assembling of the final output wave form and then spitting it
out.

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...

Colin f