[sdiy] VCO - sine output - why bother?

[Tom Wiltshire]

On 26 Aug 2016, at 10:38, Steve <sleepy_dog at gmx.de> wrote:

> Probably I'm thinking more in terms of voicecard, while the other reply I already got on this thread and yours are more in the realm of "modular and free" ;-)
> (or / and I just haven't seen enough architecture differences in typical fixed-topology synths, I've only seen a few, all rather similar, and assumed "this is how it's done")

There aren't that many that really break away from the usual VCO-VCF-VCA chain. The modulation options and possibilities tend to be what differentiates one from another. Moog got it right with the Minimoog, and everyone else recognised that. There isn't much you can do with the audio path anyway - the sound comes from the sources (VCOs) and then gets modified by the filter(s) and VCA(s). It makes sense to put the VCAs last to keep noise down. If the VCF was last, high resonance settings would tend to emphasise any background noise and you'd get a slight whistling when nothing was supposed to be playing. Another reason to have the VCA last is that it allows you to shape the sound of a oscillating filter, which is occasionally useful. 

>  Then again, when I think in the box of "subtractive synthesis", in a strict sense anyway, the suggestions of using a single sine wave to add a fundamental after a VCF feels kinda odd :-D
> I guess users of more complex (routing wise) synths have more tricks like that up their sleeves, which kinda forms this idea in my mind that next to my imagined designs to build there needs to be more room for MUX ICs on the PCB…

The only fixed-architecture synth I can think of that implements this trick is the Alesis Andromeda. There's probably one or two others, but it's certainly not a common feature.

Tom

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20160826/b0ab190a/attachment.htm>