The Polymoog resonator was a complex “three-band EQ” found on the Polymoog. The signal was separated into three frequency bands — “Low” (60-300 Hz), “Med” (300-1500 Hz), and “High” (1500-7500 Hz), and the bands could be governed by low-, high-, or band-pass filters. In the Polymoog, that was controlled by a switch; here I’ve simply created three patches that each utilize a different filter.
I’ve kept that same concept, but added a few twists. The patch can be configured in either stereo (utilizing both inputs) or “dual mono” (where the left input is split to both sides of the patch). Since frequency offsets (+/- 1 octave) can be applied to the right side of the signal path, interesting stereo separation can be achieved.
When you start to throw in modulation, the patch becomes a way to add subtle or dramatic animation to a stereo or mono-to-stereo signal. Because the filters run in parallel, modulation introduces phasing elements, while the offsets produce sweeps that ping-pong from ear to ear.
Each band has a control for gain, frequency, resonance (labeled “Emphasis,” which comes from Moog and I rather like as an alternative name for the effect), and right side offset.
Increasing resonance will increase gain, so there is some back-and-forth that needs to be played between the input gain and the resonance control. I allowed for a lot of leeway in both; WARNING: this can get LOUD. So, be mindful.
The CV inputs are set to -5 to 5Vs. The first three inputs are directed to the three bands, respectively, and an attenuverter sits above the input, so you can dial in how much modulation you want to apply.
The fourth input can select between being directed at resonance or the right offset amount; there is a pushbutton beside the input to allow you to select between the two options, with off indicating the input is directed to resonance, while on means it is directed to the offset. If modulating resonance, I feel obliged to again warn you — the patch can get very loud, so a light touch can be beneficial.
The CV outputs were designed with self-patching in mind but can be applied to other situations as well. They are -5 to 5V sine waves, loosely based on the harmonic series (the looseness is intentional; they deviate slightly from the harmonic ratios to keep the modulation interesting while echoing those relationships).
Although the patch is written for Zebu, everything except the CV inputs and outputs should work fine for ZOIA; I included some tips in the video for how to go about routing the modulation internally.
There is enough CPU to place effects before the resonantor, which can be quite interesting; see the video for more information.