MOTM

a) Such tools are used all the time at IRCAM, dating back to 1985. If you poke around enough, I
bet you will find them. Jean-Claude Risset and Barry Truaxe (I think....) were the two people
doing this. I have old issues of Computer Music Journal with 'waterfall' diagrams (what they are
called) for trumpets and clarinets. There may be a waterfall plug-in for SpectraFoo.

b) in hardware, what you need as a modified version of the Cloud Generator (cough cough). I don't
want to give away too much, but such a Fourier series thing is best done in (gasp) DSP.

Paul S.