Q-Relative Patch

See this discussion thread on MW.  A user posted an idea called a Q-Relative cell, by which he meant relative to a Quantussy cell.  While it is not a Quantussy cell, it has in common with it the idea of a cell that can be multiplied and cross-patched.

The basic idea is to use a clocked sample and hold with a random noise input to generate a random CV to be applied to the pitch of a VCO and optionally to the clock rate and to the rise and fall rate of an envelope follower.  Key ideas:

  • The changes are random, based on sampling noise.
  • A square wave into a slew limiter become a trapezoidal envelope generator.

Here is my patch diagram.  (Sorry about the quality.)  It shows four similar structures, top to bottom.  Each is made up of the following:

  • A Tromsø module with LFO, Comparator, and Sample & Hold
  • A clock divider/multiplier from the 4ms QCD
  • A quantizer from the Disting
  • A VCO , either a Klavis Twin Waves, Sync Iter, or E950
  • A VC slew, either a Mini Slew or half of a Sport Modulator

How it works

Ultra Random Analog generates two noise sources.  These are tweaked for level and color and then routed into the sample and holds.  Each noise source drives two sample & holds.

Each clock of the LFO triggers a new sample of the noise, and also drives a clock divider.  The sample is quantized and routed to the 1V/octave input of a VCO.  The divider output (conveniently a +5V square wave) is sent to a slew limiter to generate an trapezoidal envelope for controlling the signal level of the oscillator output in the output mix.  It’s a basic note generator.

The fun experiment was to have the S&H output also routed to control the slew rate of the following section and the LFO rate of the previous section, in a cycle of four.

Manual settings include LFO initial rate, LFO CV depth, Oscillator initial frequency, initial slew rate.  Here’s an example of one result.  The oscillators were tuned by ear.




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