ZOImonicon — a polyrhythmic synthesizer based on the Subharmonicon

ZOImonicon is based on the Moog Subharmonicon.

There are two oscillators (although only one has subharmonic oscillators; CPU victim), controlled by two sequencers (-/+ 2 octaves, quantized). The rhythm of these sequencers is determined by any or all of 4 rhythmic subdivisions.

Oscillator 1 has two sub-oscillators, whose frequency is based on the harmonic series. These allow you to create chords; additionally, one or both of the sub-oscillators can be controlled by the sequencer. (Oscillator 2 has no suboscillators, again, a CPU issue.)

Audio exits from the left output.

The controls mirror the Subharmonicon as closely as possible, except:

The subharmonic frequencies and the rhythmic dividers go from left (highest frequency /1, fast divider /1) to right (lowest frequency /16, slowest divider /16) which is the opposite of how the Subharmonicon’s function.


Step sequencer 1 (magenta) corresponds to controls for oscillator 1 and its suboscillators (purple).

Step sequencer 2 (blue) corresponds to controls for oscillator 2, which has no suboscillators (aqua).

The sequencers can be assigned to oscillator 1 and its two sub-oscillators independently, and to oscillator 2, using the pushbutton switches below the frequency control.

The dividers 1-4 can be assigned to either sequencer with the pushbutton switches below them (again, color corresponds).

The filter has an attack/decay envelope, which can be positively or negatively applied.

The VCA has an attack/decay envelope.

** Note about the envelopes: The Subharmonicon’s envelopes won’t retrigger during the attack phase. This is, in my opinion, one of the less-heralded awesomeness of the synthesizer; it allows you to introduce a third layer of rhythm, using the envelopes to further subdivide the sequencers. That behavior has been preserved here.

The tempo/clock is on the front page; this is the LFO which drives the dividers. The patch is not MIDI controlled, but if you wanted to clock it to MIDI, that would be where you would make your connection.

The left stompswitch will stop/start (pause) the sequencers. The middle stompswitch will reset the sequences.

On the second page is the mixer for the oscillators (only so much room on the front page). You can also watch the sequencers move through their steps on this page, whcih is a lot of fun and kind of entrancing with the polyrhythmic nature of the patch.

I have a Subharmonicon (now), and this doesn’t sound like a Subharmonicon. There is a Moog “sound” which it lacks, and the envelopes don’t open and close in quite the same way (although I tried my darnedest there). But it is a lot of fun, and the “workflow” is very like the Subharmonicon.

I want to thank Loopop for some valuable insight on an early draft of this patch, before the Subharmonicon was re-released (and I snatched one up).

No demo at the moment (very busy); I will update later when I get a chance to shoot one.

1.1 revision notes:

Minor “under the hood” changes; some adjustments to envelopes (still not quite where I want them, but better).

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  • Category: Sequencer Synthesizer
  • Revision: 1.1 -- See revision note at bottom of patch notes
  • License: Creative Commons Attribution Share Alike 4.0
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  • Modified: 3 months ago
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4 comments on “ZOImonicon — a polyrhythmic synthesizer based on the Subharmonicon
  • UncleGroOVe on said:

    Very badass (as usual, I might add)….! Can’t wait to take it for a spin!

  • Jcautobot on said:

    This is so amazing. Ive been playing around with it, I feel like it has a ton of depth. Kudos.

  • Christopher H. M. Jacques on said:

    I received a question about sending the sequencer to a MIDI output. Buckle up:

    On page #9, titled “Seq switches” there are a number of multipliers.

    The output of the top multiplier on the left side is used to control the primary oscillator of the first voice. This is really where the sequencer’s note “output” is.

    This sequencer output is combined with the parameter on the first page (titled “Controls”) that is identified as “Osc 1 freq.” To access its output, you will need to move the module (it is a renamed value module) to another page.

    Connecting both of these — the multiplier on page 9 and the Osc 1 freq value module on page 0 — to the note input of a MIDI note out module will produce note output of the primary oscillator’s sequencer.

    The gate output is much simpler.

    On the bottom of page 14 (“Div switches”) in the lefthand corner is a multiplier. Its output provides the gate for the first voice’s sequencer. To achieve the polyrhythmic effect of the envelopes, for a single voice, you could also connect the multiplier to its right, which is the gate output for the second voice’s sequencer (since both gates control the envelopes within the patch). These are the modules you would connect to the gate output of a MIDI note out module.

    After this… things become more complicated.

    The output for the second voice’s note sequence is much like the first voice’s. On page 9 again (“Seq switches”) the output of the second voice is the multiplier at the top on the right. Once again, it is combined with the parameter on page 0 (“Controls”) named “Osc 2 freq” (and once again, you will need to move the module to another page to access its output). The gate output for this voice I have already identified above.

    It may be possible (although I make no guarantees) to translate the subharmonic oscillators’ frequencies into MIDI CCs for use with a MIDI parameter like “Oscillator 2 frequency” on some synths with multiple oscillators per voice. Most of these parameters do not have the range necessary to achieve a meaningful result (most synthesizers restrict oscillator detuning to, at most, an octave). If the synthesizer did allow for such a range, it would likely take some attenuating to tune correctly.

    The subharmonic oscillator’s frequencies are found at the outputs of the CV invert modules on pages 3 & 4 (“Osc 1”).

    These could also be combined with the sequencer output for the first voice, and the Osc 1 parameter, to be sent to a separate MIDI note output.

    You may also be able to use the second voice to control a parameter like “Oscillator 2 frequency” on an outboard synth, with the same caveats as above for the subharmonic oscillators. To do this, you would take the sum output of the first voice (from the multiplier on page 9 and the Osc 1 parameter) and combine this with the inverted sum output of the second voice (this will produce the difference between the two voices at any given point).

    One of my original plans for the patch was to make a patch devoted to the sequencer, omitting the synth voice entirely. I may still attempt to do that at some point in the future, with some expanded features (perhaps adding more steps or more tracks). But for now, this is the best I have to offer.

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