[sdiy] State Var Filter with Nonlinear Feedback

[Steve Ridley]

> This is why it is called an "attractor" the function is attracted to
stable
> points which are numeric multiples.

I noticed the VCF on the old ETI/Maplin 4600 behaves in a similar
way.  I always assumed the filter clock was just soft-syncing to the
audio at multiples of the audio frequency, but maybe it's worth
another look....


Steve Ridley