Mon Jan 10 11:43:47 EST 2011

Dithering and "FAT" saw stacks

The idea: a stack of sawtooth oscillators sounds "FAT" when it's from
an analog synth.  I don't have one on hand here, but is this due to
subtle frequency changes?

Using the parabolic/cubic sawtooth generator in Pd I get a rich sound,
but the very repetitive intermodulation is a bit disturbing.

( Problem however, I do not know if I'm just paying attention to
something I wouldn't normally notice.  Unfortunately I do not have an
analog sawtooth oscillator handy. )

However, the idea in general is quite interesting.

This is related to:
  - dithering in sigma-delta
  - peak limiting in spread-spectrum pulses and ADSL[1]
  - eliminating room resonance modes in acoustics (flattening)
  - same for artificial reverberators (i.e. FDN)

Ultimately this is about integers, i.e. "almost equal" numbers.

But maybe that's not what I'm looking for.  Could this be an issue of
coupling and chaos?  I.e. if multiple saws go thorugh a discontinuity
close together, could there be some secondary cause for them to spread
apart in frequency?  I.e. modulations in a string do just that: peaks
increase the tension and thus temporarily disturb the linear order.

[1] md5://9b2913693c005de2515e3efeb8548e47