Subharmonicon II
I’ve made a re-imagined clone of the Moog Subharmonicon. A lot of credit goes to @Achro as I did use his excellent patch as a starting point. I wouldn’t have even embarked on this build if not for that patch, so big thanks are due.
Where @Achro’s patch was based on the Moogfest2018 version, this one is based on the production version which had a significantly different feature set, and also contains a bunch of other features that I wanted because, why not in the digital realm? 
I’ve called it a Subharmonicon II for lack of a better way of differentiating them.
Significant differences to the hardware
- Expanded Quantizer with ability to change root note of the scale and optionally tune the sub oscillators.
- Independent filter and amp sections for oscillator 1 and 2 (with ability to link controls).
- Stereo width for oscillator 1 and 2 (width knob acts as a crossfade if using a mono out from the patch bay).
- Ability to decouple the gates from sequencer 1 and 2.
- Spring reverb.
- PWM setting replaced with a different oscillator shape (I wasn’t enjoying the PWM setting).
- PWM input in the patch be replaced with oscillator sync (as I haven’t figured out how to PWM my splined square wave yet).
- Patch bay inputs cut down based on the philosophy that if you can cable directly to a knob, it doesn’t need to be in the patch bay.
I/O
Self-Contained
Control Section
| Control | Function | Notes |
|---|---|---|
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Tempo |
20 to 3,000 BPM. You will be dividing this down which is why it goes so high. |
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Volume |
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Start/Stop Sequencers | |
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Reset Sequencers | |
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Trigger Gates | With current sequence values. |
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Progress Sequencers | |
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Overlapping Gate Logic | XOR - exclusive or. Only a single gate will progress the sequencer. OR - Any number of overlapping gates will progress the sequencer. |
Polyrhythm Section
Each of the four knobs represent individual tempo dividers. These knobs divide the master tempo by an integer value between 1 (full left - fast) and 16 (full right - slow). Each of the resulting gates can be assigned to Sequence 1 and 2 using the SEQ assigned buttons.
Turning this on causes the progression of either sequencer to trigger the envelopes for both Oscillator 1 and 2. On is the default behaviour of the hardware.
Sequence Section
The two sequence sections represent individual four step sequencers. Sequence 1 drives Oscillator 1 and Sequence 2 drives Oscillator 2. The knob values at each of the four steps are combined with the static knobs from the Oscillator section. Values to the right Add CV to the oscillator section knobs, while values to the left Subtract CV from the oscillator section knobs. In the center position the sequence value will have no effect.
Oscillator Section
Osc 1 and 2 sections are identical.
| Control | Function | Notes |
|---|---|---|
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Main Osc Frequency | 2 octave range from middle C |
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Sub Dividers 1/2 | Divide the main osc frequency by an integer value between 1 (full left - high pitch) and 16 (full right - low pitch). |
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Octave Range Selector | Selects the octave range of the sequencer knobs. |
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Osc Wave Shape Selector | Selects wave shape for all 3 (main and sub) oscillators. See below for notes on wave shapes. |
Oscillator Shapes
Square - roughly based on an image of the square wave from a Sub Phatty (I think…) using a spline node.
Batman - based on ducking a sine wave and using that as the carrier for the above square wave.
Saw - based on discrete-time modelling of the saw wave from a Minimoog Voyager from this article.
Mixer Section
Mixer 1 and 2 sections are identical.
| Control | Function | Notes |
|---|---|---|
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Sequencer Assignment | Determines which knobs from the oscillator section will be affected by the sequencer. If no buttons are lit, the sequencer has no effect. Seq 1 drives Osc 1; Seq 2 drives Osc 2. |
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Oscillator Volumes | |
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Oscillator Stereo Spread | Oscillators can be spread to either side. Centre position is mono. If using a single audio out from the patch bay, this knob functions as a cross fade. |
Filter Section
Filter 1 and 2 sections are identical.
| Control | Function | Notes |
|---|---|---|
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Cutoff | |
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Resonance | |
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EG Amount | Positive and negative amounts. Centre position has no effect. |
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Attack | |
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Release | |
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Link | Filter & Amp 1 knobs also control Filter & Amp 2. |
Amplifier Section
Amp 1 and 2 sections are identical. Note that the link button above also affects the amp section.
Filter 1 and 2 sections are identical.
| Control | Function | Notes |
|---|---|---|
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Attack, Release. Drone |
Bypasses the amp envelope. Envelope is still available at the patch bay. |
Reverb Section
Standard spring reverb module applied separately to Oscillator 1 and 2.
Patch Bay
| Control | Signal Range | Notes |
|---|---|---|
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Gate 0-1 | Run the sequencers from here when the internal clock is stopped. |
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Gate 0-1 | Reset the sequencers and clocks (same as Reset button). |
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Gate 0-1 | Trigger both envelopes (same as Trigger button). |
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Gate 0-1 | Trigger Filter and Amp for Oscillator 1. Same for Gate 2. |
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Modulation 0-1 | Oscillator Sync for primary Oscillator 1 (not the subs). Same for Sync 2. |
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Gate 0-1 | Master clock out. |
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Gate 0-1 | Individual clock out for Rhythm generator 1. Same for Rhythm 2-4. |
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Modulation 0-1 | Envelope out. Same for VCA and VCF EG 1 and 2. |
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Gate 0-1 | Gate out for Sequencer 1. Same for Gate 2. |
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Modulation 0-1 | Sequence 1 values. Same for Seq 2. |
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Audio -1 to 1 | Audio out L/R. If only using one, the Width knob acts as a crossfade. |
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Audio -1 to 1 | Intermediate audio outs from the oscillators. Note these are not DC Blocked, mainly because the sub outs make good glitchy Modulation sources, especially on the square wave setting when the pitch is really low. The sub outs are capable of generating pitches below 20hz. This can damage your speakers so if you are using these outs for audio, just make sure you include a DC Blocker node somewhere in your audio path. The main outs (L/R) and internal speaker are both DC Blocked. |
Version History
| Revision | File | Date | Notes |
|---|---|---|---|
| 1.0 | Subharmonicon II.audulus (1.2 MB) | 11/28/2020 |
Demos
Patch come set up for a demo. Just open the patch and press Play 
Such a good layout.
another one knocked straight out of the park!!! WELL DONE 
