[sdiy] Interesting Through-Zero VCO

[Don Tillman]

   > From: "Theo" <t.hogers at home.nl>
   > Date: Wed, 31 Dec 2003 03:41:49 +0100
   > 
   > Maybe Jurgen Michaelis (JoMoX) Resonator Nuronium fits the bill?

This guy?

http://www.jayemsonic.de/

Um, not really.  JH and I are talking about a 2-pole VCF that can be
tuned to negative frequencies in a manner similar to the digital
oscillators in the Yamaha DX7.  

Synth players have used audio modulation of a VCF for a long time.
(There's the classic 'chih-chih chu-chu chuh-chuh' solo in Edgar
Winter's 'Frankenstein'.)   But this would be a little different.

JH suggested a high resonance thru-zero VCF.  That would be something
like a thru-zero VCO in FM synthesis but also something like a regular
filter.

I'm thinking of a low resonance thru-zero VCF typically tuned near 
0 Hz.  Of course a Low Pass VCF isn't very useful tuned near 0 Hz, so
this would be a High Pass, All Pass or Notch filter.  And you could
have an LFO modulate it through 0 Hz for a chorusey sound, or audio
modulate it for warping waveforms.

But I'm just thinking out loud with some inspiration from Henry
Walmsley's circuit.  I've never tried anything remotely like this.

  -- Don

-- 
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com