Aeolian Harmonic Patching in Stereo, with Wavefolding and TZFM

Core Techniques:

  • Harmonic chord progression using Harmonàig
  • Audio rate XOR voice combination
  • Rhythmic modulation
  • Wavefolding
  • Through-zero frequency modulation

I explore quite a few techniques in this patch. The foundation is a minor chord progression built around a diad patched in stereo (root left and 3rd right). I wanted to use similar timbres for the voices producing root and 3rd. The root comes from the wavefolder output of a Neóni which is modulated by a rhythmic LFO. The 3rd is a TZFM pair pitched from the Tš-L modulating a second Neóni. The index ratio is modulated by a second rhythmic LFO.

Self patching an øchd produces the rhythmic LFO signals that become the natual tempo and feel of the patch. I play the progression manually from the Harmonàig as the rhythms are not rigidly locked.

The 5th output of the Harmonàig controls a Tòna from which the square wave output is combined with the root Neóni’s squarewave via the XOR comparator on the eãs. XOR processing of square waves is mathematically the same as ring-modulation/4-quadrant multiplication of the two square wave signals. Sidebands are produced resulting in a richer more complex tone. As the chord voicings mostly form a perfect 5th interval between root and 5th, the resulting signal remains tonally stable. Slight detuning of the 5th allowing for beating to broaden the timbre.

I low-pass filter this new voice and share it equally between left and right to form a common mono signal for the patch.

The gate from the Harmonàig triggers an ADSR from the Cèis. TRIG mode is engaged to force completion of the attack phase.
This envelope modulates two aspects of the same signal.
The top voice of a Cš-L acts as an LFO. This LFO frequency is controlled by the envelope while the signal’s depth is simultaniously controlled by the same envelope.

The processed LFO controls the cutoff frequency of the I-ō47 which is low-pass filtering the XOR signal.
When a note is played on the Harmonàig the filter cutoff will “wobble” with a dynamic rate and depth.