Interesting Paper available on Moog VCF

Don Tillman don at
Wed Sep 18 22:53:04 CEST 1996

   Date: Tue, 17 Sep 1996 14:16:26 -0700 (PDT)
   From: Sean Costello <costello at>

   Judging from the source of the Moog VCF paper (Julius Smith at Stanford),
   the digital Moog money would be going to Yamaha.  Yamaha has subsidized work
   at Stanford for a long time; first the FM stuff with Chowning, and now the
   physical modelling work of Julius Smith and Perry Cook.  My bet is that
   there is a "Virtual Moog" in the works at both CCRMA and Yamaha; another one
   of Stilson's papers was how to simulate "classic" analog waveforms in the
   digital domain. 

I don't think that's the case.  My understanding is that this is just
regular research at CCRMA and they got moles of royalties from Yamaha
from the licensing of the DX-7 patent from before.

But Julius plays in my band so I can ask him at the next rehearsal.

(This won't surpise you; his main axe is the Yamaha VL-1.)

   The Moog VCF paper wasn't even concerned with simulating the particular
   quirks of the Moog filter; it was simply trying to come up with a digital
   simulation of a filter that used four identical one-pole filters that were
   cascaded, with feedback going around all four (you know what I mean - I
   can't explain it too well due to my lousy technical abilities).  This is as
   much a simulation of an ARP 4075, SSM 2040 or CEM 3320 as it is a simulation
   of the Moog filter.  

Yes indeed.  I find it completely amazing how complex the effects of
four little dirt-simple integrators in a row can be in the digital

  -- Don

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