[sdiy] Shruthi 4PM (was re something else...)

[Olivier Gillet]

> Only thing so far I've seen that might be a problem is what Olivier
> mentioned about the first filter stage being bypassed.
>
> Ideas, comments?

This is something I was really interested in, and I designed two
modules in the process:
1/ A digitally controlled 4 channel mixer which allows gain
configurations to be stored and interpolated between - to which I fed
the inputs from a Dr Octature or:
2/ A 4-pole cascade in which each stage is continuously variable
between 1-pole VCF/VCA, coupled or independent control of each stage,
patch points between stages, and a spare VCA cell which could be
patched for resonance - the whole thing meant to be a "filter
construction set".

The result is that there are very few sweet spots yielding interesting
transfer functions. Between them there's a large mass of muddy, nasal,
band-passey things. I ended up using 1/ for plenty of things not
related to transfer function building; and I let 2/ rot in a drawer.

Olivier