[sdiy] Fun things to do with a half SSM2164?

Olivier Gillet ol.gillet at gmail.com
Sun Jun 13 14:52:46 CEST 2010


Hi all,

Thanks for the suggestions... I've just breadboarded a 1-pole HPF
before the SSM2044 and it's working great (It only cost me an extra
dual op-amp. Most of the other suggestions (modulating modulation
amounts, ring-modulation are already done in software). The remaining
cell will probably be used to modulate the cutoff frequency with a
variable amount of the input audio.

Pole-mixing would have been possible if the SSM2044 exposed a bit more
of its internal signals - but it's an idea I will keep in mind for a
future filter.

Regarding the envelopes, there are bunch of reasons why I decided to
go with the linearization:
- the envelopes already have a non-linear response (piecewise linear
decay and release ; linear attack). Since they can be routed either to
internal parameters (oscillator frequency, PWM) or external CV, I
found it more consistent if they behaved similarly for all modulation
destinations.
- I gave a shot at the non-linear version too, and the main obstacle
was that for a large range of the sustain parameter value, the
attenuation was too strong.
- The other filter/VCA boards I have so far have linear VCAs.

Olivier



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