[sdiy] Multi-Input filters

[Osamu (Sam) HOSHUYAMA]

Hello Tim,

I designed a multi-input multi-mode filter, but not tested yet, 
though it's in my "to build in Canada" list.

  http://www5b.biglobe.ne.jp/~houshu/synth/VcSvf01a.gif

I think we can't call it "state variable filter" because there 
is no explicit "state variables" in the structure for LPF and 
HPF inputs.  We can call it just "biquad (2-pole) filter".

A Japanese diyer said he developed a BPF modification based 
on the MS-20 filter, which results in almost the same function 
as the Synthacon filter.  I'll try to ask him to put the 
schematic available online.

Best,
Sam Hoshuyama

Tim Ressel wrote:
> 
> Yo,
> 
> I was fascinated by Ken Stone's description of his
> Synthacon filter.
> 
> http://www.cgs.synth.net/modules/cgs35_syntha_vcf.html
> 
> Especially the part about having different sources
> driving the various inputs. I was wondering if this
> trick could be applied to a state-variable filter? I'm
> thinking the inputs would be applied to the integrator
> summing node or buffer, depending on the filter
> design.
> 
> Thoughts?
> 
> --Tim
-- - ---  - -- ------ - -------- -- - ---- -
Osamu (Sam) HOSHUYAMA      houshu at rogers.com
                              Ottawa, CANADA
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