Do filters add up??

[Wim Verheyen]

At 15:44 21/07/97 -0500, you wrote:
>I have a state-variable filter which has a 12db/oct low pass response,
>among others.  If I put two of these in series, with the same cutoff
>frequency and resonance, would that yield 24db/oct overall?

Yes, but if you do filter sweeps, you have to apply the same control
voltage to both filters, and they have to track fairly good.
I use this trick in my Aemit synth. It has two independent 12dB filters,
but with a switch I can let filter 1 control filter 2. If I tune both
filters and I patch out 1 to in 2, I have a 24dB on out 2.
The nice thing is that the controls on filter 2 stay active, so I can offset
it to filter 1 and apply separate modulation, not 24dB strictly anymore but
the 
sounds are worth it. 

-------------------------------------------------
 Wim Verheyen, Hasselt, Belgium, catwim at innet.be
 The Aemit modular analog home :
 http://www.club.innet.be/~year0828/wim.html
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