Calculus not being my fote - can the FFT be broken/summed up into 4 frequency blocks?
I have a few of http://diylightanimation.com/wiki/index.php?title=Manual_SSR4- that are four channel SSR type mains light controllers - and would like break down into 4 channels to drive each switch.
I built scads of Color organs back in the late 60's, so i understand how to turn on a triac, but doing it digitally seems to be lots more fun...