[sdiy] Formant filters, yay!

[Richie Burnett]

> I've done similar stuff with sine or triangles oscs (although you can try 
> squares and ramps for fun, obviously). The key part is the "windowing"...

Tom, I remember you making a demo video of this running on a dsPIC a long 
time ago.  Weren't you trying to implement the "resonant low-pass" waveform 
from a casio CZ synth at the time?

>From what I recall it's possible to mimic other filter types like high-pass 
and band-pass too using this technique, by messing about with the phase 
where the sinusoidal oscillation starts from when it is sync'ed by the lower 
frequency windowing function.

-Richie,