So I had a half cocked idea, looked around a bit and couldn't find an instance of someone doing it before, so I figured I'd ask if it's been done.
Could you make a sidechain-able LFO? Such that gain peaks from the side signal would cause an adjustment of one of the parameters (or several).
It wouldn't be terribly hard to do in max/MSP and I can imagine it might make for some interesting sounds. I suppose you could really do the same thing in live by going along with automation after recording but where's the fun in that?
So the question is has it been done, and if not, why not?
So I imagine this would probably equate to modulating the depth parameter, likely in time with the track. Some synths that would allow you to do this are massive and dcam synthsquad, and I'm pretty sure you could set this up with any of FabFilter plugins, synths and effects. Plus yea, whatever weird stuff you could do with max/msp.
I think what I'd probably do would be make a m4l patch or external VST that you could map midi parameters to (ie the knobs) and input your sidechain signal to. Use either the gain values or the frequency values of the signal to alter each midi parameter in a couple of different optioned ways. That way you could do it for pretty much any effect. Also maybe put a delay on the parameter change as well.