[sdiy] 40-band vocorder

[Tony Clark]

>>> Anyhoo, yeah, as said it's one of those cases where more isn't
>>> necessarily better. Someone a while back asked about a "more pole"
>>> filter (that is one having more than the standard 2-4), and thing
>>> is a 3 doesn't sound much different than a 4, and it's less and
>>> less after that.
>>>
>>> Another thing that filter stages do is phase shift the signal by 45
>>> degrees, and there's other EE stuffs that make this not neccicarily
>>> something you want.
>
> Uh - wait a minute - it depends on what those various poles are doing.
> If you're talking about a straight  lowpass, sure, you won't notice
> much of a difference beyond 4 poles. But if you're setting up specific
> resonances, bring on those poles!

   Exactly correct.  It's in the resonant mode that brings out the unique
characteristics of higher poled filters as cut-off becomes less
important to the overall sound that comes out.
   For a vocoder, the importance here is in band overlap, and with 40
bands, the roll off is going to have to be pretty steep.  I remember
looking into doing a vocoder at one point a long time ago, and figuring
out all the values for each filter.  All I've got to say is:
   Good luck!  I'm rooting for you!

   Tony

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