state var allpass output

[Don Tillman]

   Date: Fri, 26 Feb 1999 11:59:58 -0500
   From: "Michael B. Irwin" <mirwin1 at istar.ca>

   Regarding using a state-variable filter to obtain an allpass response,
   last year I designed a 3-notch phaser using a cascade of state-variable
   allpass ( not notch ) sections  with summation of the output with the
   input in standard phaser fashion. Voltage-controlled Q was included, as
   well as a resonance control. 

This sounds like a great approach!

Yet another sound animation circuit I'm going to have to build
someday.  (I need to take a season off from my day job.)

  -- Don