[sdiy] From a commercial standpoint -- has Eurorack "won"?

Neil Johnson neil.johnson71 at gmail.com
Tue May 3 12:23:16 CEST 2016

> It's mainly because resonance is not a voltage-controlled parameter in most
> filter designs. It's just a potentiometer in the resonance feedback loop.
> For one or more of several reasons, few designers choose to construct a VC
> replacement for it.
> Unless it's a modern digitally controlled analog synths, then we do it all
> the time as Paul M pointed out.

Pretty much every analogue polysynth has CV-controlled filter Q.  In
most cases this is just another input to a SSM/CEM/IRxxx chip on ht
evoice module/board.  Of the ones I've looked at:
- Oberheim OBX
- Siel Opera 6
- Roland MKS-70

As to whether you can modulate it with anything other than the setting
knob is a separate matter.  It tends to be a voice-common parameter
(one CV for all voices) which somewhat limits what makes suitable
modulators -- I guess mod wheel, foot pedal, global LFO are about it.

Larger polysynths (e.g., Oberheim Matrix 12) with per-voice resonance
CVs, and more recent polysnths that off-load the voice control to
per-voice microntrollers, make it easier to apply EGs or other
note-specific modulation to individual note's filter Q.


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