[sdiy] Basic Synth Patch? VCO-VCF-VCA

[Ingo Debus]

Am Sonntag, 30.11.03 um 05:24 Uhr schrieb Michael Boracci:

> Harry> You could also sum the "AM" signal with the envelope and get 
> the AM
> mod you wanted from a single VCA.
>
> This is a really great solution Harry. I did not consider that, but it 
> makes
> a lot of sense and would probably be the way to go in order to 
> integrate
> several functions in to one circuit.
>

Summing the envelope cv and the AM cv might not give the expected 
result here. If the envelope is completely finished (at zero) and an AM 
cv (say, a LF sine) is applied you would still hear something. If the 
VCA is adjusted in such a way that zero cv from the envelope is a lower 
voltage than required to shut the VCA completely off, then the envelope 
gets "distorted": parts of the attack and release phase are cut off.

I think what we really want  here is multiplying both CVs. But to do 
this we'd need another VCA...

The (old) Formant VCA module had two VCAs in series: one for the 
envelope and one for AM.

Ingo