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implementation of polyphony in korg ps-3100

2010-02-19 by Monroe Eskew

This is probably old news to some of you, but I was just reading about
the Korg PS-3100 analog synth and it is interesting how they did the
polyphony.  They just had twelve fixed oscillators, one for each note
on the scale, and then frequency dividers to go down in octaves.  Then
each of the 48 keys controlled a separate gate with its own envelope,
VCA, and VCF.  The oscillators just hummed along with no voltage
control besides uniform pitch bend via a wheel.

That is quite different from how analog synthesis is usually done
these days, and seems to use a lot of machinery to get it done-- i.e.
48 independent VCAs.  However this same kind of idea might be useful
in a big modular rack with sequencers and all.  Imagine a module
consisting in twelve oscillators, each with only a pot for its
frequency, no voltage control.  There may be switches for waveform.
Then with a bunch of frequency dividers, VCAs, VCFs etc, one could
replicate the Korg architecture.  It's a different way of doing
things, and it is probably less efficient and less flexible, but it
may be useful once in a while.  If we scaled it down to say 4
oscillators and used some of Doepfer's current and forthcoming quad
modules, this may actually save space and money-- given a simple
non-VC quad osc module.  Something to think about at least, to expand
the patch-possibilities in your mind.

Monroe

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