[sdiy] 3 Pole state-variable filters

[Theo]

I think a 18dB statevariable would result in a filter with 4 outputs.
HP, LP and two BP outputs, one BP output with a slightly steeper HP side
and one with a slightly steeper LP side.
Combining the two BP outputs may give you the equally "distributed" BP
response.

Theo


From: jhaible <jhaible at debitel.net>

> > I'm currently working on an 18dB state-variable filter (LP/BP/HP at the
> > SAME time, unlike the Formant).  The maths gets a bit hairy,
>
> >Its not too bad if you're familiar with s-plane math.
>
> 3 poles for HP and LP make sense. I think 3 poles on BP would mean
> you spend one pair for the BP function, and then decide whether to
> steepen the upper or the lower slope (i.e. adding a real pole LPF or HPF).
> Or is there a way to "distribute" 3 poles equally on both slopes of a
> BPF function ?
>
> JH.
>
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