Design your own waveform synths?

[Martin Czech]

> Actually, after I wrote my first post I realized my error.   What I'm now thinking
> about is a filter which would have extremely precision controlled timing.  Say we
> take a sawtooth wave and give it low-pass filtering below 2500 Hz for 150 ms, then
> increase the cut-off to 5500 Hz over the next 50 ms, then break out into two
> band-pass filters, 400 Hz wide, one at 5500 Hz, the other at 6500 for 75 ms, then
> have them smoothly merge back into one 400 Hz wide band at 6000 Hz over the next 500
> ms before gradually spreading the lower cutoff back down to zero Hz over the next 2
> seconds.  Customizable waveforms could do the same thing, but I see now that
> filtering really is the trick to do it logically and with control.  Do instruments
> exist with such precision timing over filter control?  All I've ever played with is
> analogs that just give ADSR filter control, but none of it approaches the degree of
> timing, control and filter variation that I'm thinking about.
> 
> Robert
> 
Modulating a filter that fast means you are out of LTI (linear time invariant)
systems. New partials will be generated, which were not there in the input.

Practical realisations will suffer from control voltage speakthrough,
and also accuracy is an issue (thinking about 1000:1 sweeps).

m.c.