Moog Subharmonicon: What's New, What's Changed?

Moog's polyrhythmic playground gets some great improvements in its transition from workshop to retail

Published May 12, 2020 by John G.

Moog Subharmonicon is the latest addition to Moog's growing family of tabletop semi-modular analog synthesizer modules, arriving in the same size case as its siblings Mother-32 and DFAM and sharing the same friendliness toward eurorack setups. Subharmonicon combines two VCOs and two subharmonic oscillators per VCO with two four-step sequencers and four rhythm generators to make one of Moog's most unique synths.

Much was written about Subharmonicon when it was announced as the synthesizer that would be built by ±120 lucky holders of the 'Engineer Pass' in an exclusive VIP workshop at Moogfest 2018. Moog itself includes a useful appendix in the product copy for the new retail version and a 'brief history' introduction in the user's manual about Subharmonicon's origins in the Schillinger System and its dual inspirations Trautonium and Rhythmicon.

So rather than rehash all that here, let's take a look instead at some of what's changed on Subharmonicon in its transition from a hand-built limited edition to a shipping product assembled by employee-owners at the Moog Factory in Asheville, North Carolina, USA.

3/4 view of Moog DFAM, Moog Mother-32 and Moog Subharmonicon in 3-tier rack showing top, left side and front edge
None more black
The first thing you'll notice is that like DFAM before it, Subharmonicon has adopted Mother-32's white-on-black colorway instead of the black-on-unfinished-metal top panels both synths had for their original builds. The prototype style was cool for the workshop versions and will distinguish those limited editions at a glance, but the standard livery makes Subharmonicon aesthetically a better Moog semi-modular citizen alongside Mother-32 and DFAM.
collage image with name plate detail illustration from Moog Subharmonicon workshop edition above name plate detail image from Moog Subharmonicon retail edition

Subtitles on
Speaking of those top panels, on the workshop version alongside the name SUBHARMONICON it is further described as a 'semi-modular analog synthesizer,' the exact same phrase that adorns Mother-32. At least DFAM got its own identity as the expanded acronym 'drummer from another mother!'

Now in its final form, Subharmonicon has gained a word in its somewhat unwieldy but now distinct 'subtitle' that hints at its reliance on a unique 4-step sequencer + 'rhythm generator' combo for much of its mojo: it is now described as a 'semi-modular polyrhythmic analog synthesizer.'
collage image with name plate detail illustration from Moog Subharmonicon workshop edition above name plate detail image from Moog Subharmonicon retail edition
detail image of Moog Subharmonicon panel showing quantize controls

One of these days, I'm gonna get quantiz-izized
Probably the biggest improvement on the new Subharmonicon is the addition of a pitch quantizer for the sequencers and rhythm generators. While it was never really a complaint about the workshop edition per se, users of same have definitely commented on how tricky it can be to tune a Subharmonicon sequence, particularly given the scaled interplay among the main VCO tunings and those of the subharmonic oscillators, as well as how easy it can be to tip a sequence from harmonious to dissonant with an errant brush of a tuning knob.

Now, Subharmonicon can hew sequencer pitches to 12- or 8-step equal temperament, 8-step diatonic or 8-step just intonation scales. Purists can also leave the quantizer off for fussier authentic-to-the-original behavior.
detail image of Moog Subharmonicon panel showing VCO1 waveform selector switch

Determinant waves
The VCOs and subharmonic oscillators on the original Subharmonicon only output sawtooth waveforms, but the new model gains some new controls with new wave options. You can choose the original all-sawtooth lineup, switch either or both VCOs and their subharmonic oscillators to all squares, or use the middle position, which Moog describes as a 'special case' where the subharmonic oscillators both output sawtooth waves while the main VCO outputs a square wave.

In the middle position, the sawtooth output of the first subharmonic oscillator is by default normalled to modulate the pulse width of the main VCO's square wave.
detail image of Moog Subharmonicon panel showing VCO1 waveform selector switch
detail illustration of Moog Subharmonicon patch panel showing MIDI input
Living for the MIDI
Replacing the TEMPO patch point from the original Subharmonicon is a welcome new 3.5mm MIDI input. Moog helpfully provides a 5-pin adapter dongle in the box, and showing great attention to detail they even specify that it's Type B, indicating that the patch socket's tip-, ring- and sleeve-to-pin assignments are wired up 'Korg style' as opposed to 'Arturia style.'
collage image with patch panel detail illustration from Moog Subharmonicon workshop edition to the left of patch panel detail image from Moog Subharmonicon retail edition
Nick Batt has entered the chat
Speaking of patch panel swap-outs, we've lost pitch CV inputs for both VCOs' SUB 2 subharmonic oscillators and gained PWM inputs to modulate the pulse widths of the VCOs when they're outputting square waves. Connections made to these new pulse width modulation inputs will override the aforementioned internally-wired connection between a SUB 1 sawtooth wave and the pulse width of its main VCO when that VCO's wave selector switch is in the middle position.
collage image with patch panel detail illustration from Moog Subharmonicon workshop edition to the left of patch panel detail image from Moog Subharmonicon retail edition
detail image of Moog Subharmonicon panel showing sequencer octave range controls
Driving range
At a glance, you might assume this new control just cycles through different octaves for your sequencer steps (I did), but it actually sets the range available for each of the STEP knobs in Subharmonicon's sequencers, with settings available for one octave above and below the current VCO frequency, two octaves above and below and five octaves above and below. There's also a special mode you can engage that locks the patch panel's sequencer CV outputs to ±5 while you use another range for the internal sequencer.
collage image with sequencer control detail illustration from Moog Subharmonicon workshop edition above sequencer control detail image from Moog Subharmonicon retail edition

It's lit, fellow kids
Many Subharmonicon functions previously consigned to toggle switches have been rearranged, and are now controlled by latching, internally-lit buttons. Some may consider this a matter of preference, but this change arguably enhances the 'performability' of these controls, allowing for easier on/off toggles individually or en masse, along with providing better visual feedback in dark stage or studio environments. Why red rather than Moog's typical amber lamps? A question for the ages!

Some of the most extensive rearrangement has happened around the controls used to assign sequencers to VCOs and subharmonic oscillators, and the controls used to assign rhythm generators to sequencers, providing new options and enhanced flexibility to both functions.
collage image with sequencer control detail illustration from Moog Subharmonicon workshop edition above sequencer control detail image from Moog Subharmonicon retail edition
detail image of Moog Subharmonicon panel showing sequencer control buttons with EG button lit

New buttons, e.g., EG
Pretty easy to guess that the initials on this new button stand for 'envelope generator,' but maybe not so obvious is what exactly it does in its three states: lit, unlit or blinking.

When lit, the internal sequencer behaves as you'd expect, with each step triggering both envelope generators in addition to sending pitch values. When the button is unlit, sequencer steps will not trigger the EGs, leaving that instead to signals received via the patch panel's TRIGGER CV input.

When the EG button is blinking, the both the filter and amp are held open so that you can carefully tune the VCO and subharmonic oscillator pitch values as well as those for each sequencer step.
collage image with sequencer control detail illustration from Moog Subharmonicon workshop edition above sequencer control detail image from Moog Subharmonicon retail edition
Attack knobs...acquired
Where the workshop edition had three-position toggle switches to control the attack segments of its amp and filter envelopes – and just three fixed attack times to go with them – the new Subharmonicon has full-range attack potentiometers with Moog's standard Bakelite knob caps. These luxurious controls can set attack times anywhere from 1 millisecond to 10 seconds.
collage image with sequencer control detail illustration from Moog Subharmonicon workshop edition above sequencer control detail image from Moog Subharmonicon retail edition
collage image with VCO mixer control detail illustration from Moog Subharmonicon workshop edition to the left of VCO mixer control detail image from Moog Subharmonicon retail edition
Shafts' big score
Along similar lines, rearranging the Subharmonicon top panel apparently opened up enough real estate for the VCO mixer controls that were mere pot shafts on the workshop edition to gain their own knob caps, albeit slightly smaller than the massive attack knobs.

On balance, it's a great update to an already fascinating instrument. Tiny removals like toggle switches and SUB 2 CV inputs pale in comparison to the wealth of thoughtful additions, particularly the pitch quantizer and MIDI input. Those already building a Mother-32/DFAM semi-modular rig will welcome this new addition, while for holdouts Subharmonicon may be what finally pushes them over the edge.

You can read more about Subharmonicon and its aforementioned backstory over on our product page, where you'll also find the full Moog Subharmonicon manual so that you can dig deeper and find changes we might've left out here. While you're there, make sure to introduce yourself to the rest of the Moog semi-modular family by checking out our bundles for Mother-32 and DFAM, any of which can be customized by a Kraft Music Sales Advisor to include Subharmonicon.

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