[sdiy] dual VCFs

[harrybissell]

Hiya Crystal

I have done this. I used the EFM version of the MS-20 filter (Sallen-Key)
which all told I'm not thrilled with. That is a filter problem...

I'd probably choose the state variable as a basis

I can set each filter to low or high pass, run them in series, or parallel.

I have individual frequency controls... and a common control. One CV will
drive both filters in the same direction (cutoff) and the other will drive
them
in opposite directions (bandwidth ?)

It would be a nice filter but the filter elements themselves are not so nice
imho.
The MS-20 has a lot of interaction with input level and resonance which makes
the
series / parallel connection REALLY squirrely !

H^) harry

crystal wrote:

> as y'all can probably tell by this, my third post tonight, i am about to
> start to DIY again (finally).
>
> for my first real project in a few years i am considering building a dual
> VCF module with the capabilities for VC Band Width, VCcenter freq tracking
> maybe with INVERT option on one VC, and maybe some built in overdrive too.
> HP/BP on one, BP/LP on the other.
>
> any comments from those who have done this (or something similar)?
>
> any neat ideas?