A new instrument: Moog's Minimoog and Memorymoog #51

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opened 2026-10-12 23:32:36 +00:00 by bcox · 0 comments

bcox commented

2026-10-12 23:32:36 +00:00

Owner

Everything below is from recollection and a quick look at encyclopedia and shop pages, with no manual read; issue #20's list was wrong in several places for the same reason. Find and read Moog's owner's and service manuals before designing anything, put them in docs/references.md, and correct this.

What it covers

One instrument, a voice and N of it, as a SEM and the OB-X are, and as the Prophet-5 and the Prophet-10 are:

Minimoog Model D (1970). One voice: three VCOs, each at one of six fixed waveforms and six ranges, the third able to leave the keyboard and run slow as the modulation source; white or pink noise; an external input; a mixer that can be overdriven; the four-pole transistor ladder low-pass with keyboard control in thirds by two switches; two contours of attack, decay and sustain, whose decay is also the release when a switch says so; a modulation mix of the third VCO and noise, sent to the oscillators and the filter by switches at a depth the wheel sets; glide.
Memorymoog (1982). Six voices, each three VCOs (sawtooth, triangle and a pulse of variable width, any together), the second able to be synchronized to the first, the third able to leave the keyboard and run slow; noise; the ladder filter; two ADSR contours; one LFO in several shapes to the oscillators, the pulse widths and the filter; and voice modulation, the third VCO and the filter's contour sent inside each voice to the other VCOs' pitch, their pulse widths and the filter. A mono mode that stacks the voices, with a choice of key priority; glide.
Memorymoog Plus (1984): the same with MIDI and a sequencer. Nothing of the voice changes, so it is covered by name only.

A Minimoog is then voice.count 1 and a Memorymoog voice with a few things at nothing; a Memorymoog is six.

To find out

Whether the Minimoog really is settings of the Memorymoog's voice. What the Minimoog has that the Memorymoog lacks, as recalled: the "sharktooth" waveform (which may be a mixture of the triangle and the sawtooth, and so a setting), the reverse sawtooth on the third VCO, two fixed narrow pulses (settings of a width), noise as a modulation source, pink noise, contours with no release of their own, and the filter's keyboard control in thirds. Each looks like a parameter. The manuals decide.
The mixer's overdrive and the feedback trick, the output patched back into the external input. These are most of what a Minimoog is known for after its filter, and both are tone. They wait on #4, and the second on #17.
Voice modulation is the Prophet's POLY-MOD in all but name, and should be done the way that was: worked out every sample for the oscillator's share, with the filter run a few samples at a time for the Pi's sake.
Cost on the Pi. Three VCOs a voice at six voices, with audio-rate modulation, is more per voice than anything here. Measure early.
Which Minimoog. The oscillator board changed during its run. One is modelled; the others are #4's switches.

What it does not cover

Patch memory, the Memorymoog's cassette interface and its auto-tune, by Ben's word that memory is irrelevant. The Memorymoog's arpeggiator is engine/arpeggiator.h. Its chord memory and hold are #11. The Memorymoog Plus's sequencer would be an issue of its own, as #2 and #5 are.

Later, perhaps, by Ben's word on #26: things from the Voyager, which he counts as a Minimoog reissued with additions and so allowed, as the OB-X8 is. They would be settings of this instrument, as the SEM family took a few of the OB-X8's. Not now.

What is already here to build on

engine/four_pole_filter.h: four stages with feedback, already the SH-5's ladder. What makes Moog's sound as it does is how it saturates, which is #4. A Moog built clean will sound close to what is here already, so this instrument leans on #4 more than any other.
engine/analog_vco.h: sawtooth, pulse and triangle at once from one ramp, with sync, which is the Memorymoog's VCO as recalled.
The Prophet's voice.h, for POLY-MOD and for an oscillator that leaves the keyboard and runs slow.
engine/key_assign.h, engine/portamento.h, engine/variance.h, engine/zones.h, the shared arpeggiator and effects.

Provenance

The Memorymoog has a processor and patch memory. Rule 3: no firmware disassembly. Rule 4: none of Moog's programs.
Rule 2: the Minimoog has more emulations than any instrument. None's code may be read for more than how a problem is structured, and nothing lifted. Fidelity is judged against the manuals and recordings.
The names. "Moog" and the model names are trademarks that are actively used and defended. Ben said on 2026-10-12 to use Moog's own names for now, so that he can tell what each is, the repository being private; nearly every instrument's name here will have to change before anything is sold, and these with them. So, say, instruments/minimoog/ and programs named minimoog.

Ben decided on 2026-10-12, on #26, that the Moogs up to the Memorymoog are wanted, with variants combined where that fits, and asked for an issue for each instrument that makes. This is one of five; the others are linked from #26. Not started. **Everything below is from recollection and a quick look at encyclopedia and shop pages, with no manual read**; issue #20's list was wrong in several places for the same reason. Find and read Moog's owner's and service manuals before designing anything, put them in `docs/references.md`, and correct this. ## What it covers One instrument, a voice and N of it, as a SEM and the OB-X are, and as the Prophet-5 and the Prophet-10 are: - **Minimoog Model D** (1970). One voice: three VCOs, each at one of six fixed waveforms and six ranges, the third able to leave the keyboard and run slow as the modulation source; white or pink noise; an external input; a mixer that can be overdriven; the four-pole transistor ladder low-pass with keyboard control in thirds by two switches; two contours of attack, decay and sustain, whose decay is also the release when a switch says so; a modulation mix of the third VCO and noise, sent to the oscillators and the filter by switches at a depth the wheel sets; glide. - **Memorymoog** (1982). Six voices, each three VCOs (sawtooth, triangle and a pulse of variable width, any together), the second able to be synchronized to the first, the third able to leave the keyboard and run slow; noise; the ladder filter; two ADSR contours; one LFO in several shapes to the oscillators, the pulse widths and the filter; and voice modulation, the third VCO and the filter's contour sent inside each voice to the other VCOs' pitch, their pulse widths and the filter. A mono mode that stacks the voices, with a choice of key priority; glide. - **Memorymoog Plus** (1984): the same with MIDI and a sequencer. Nothing of the voice changes, so it is covered by name only. A Minimoog is then `voice.count` 1 and a Memorymoog voice with a few things at nothing; a Memorymoog is six. ## To find out - **Whether the Minimoog really is settings of the Memorymoog's voice.** What the Minimoog has that the Memorymoog lacks, as recalled: the "sharktooth" waveform (which may be a mixture of the triangle and the sawtooth, and so a setting), the reverse sawtooth on the third VCO, two fixed narrow pulses (settings of a width), noise as a modulation source, pink noise, contours with no release of their own, and the filter's keyboard control in thirds. Each looks like a parameter. The manuals decide. - **The mixer's overdrive and the feedback trick**, the output patched back into the external input. These are most of what a Minimoog is known for after its filter, and both are tone. They wait on #4, and the second on #17. - **Voice modulation** is the Prophet's POLY-MOD in all but name, and should be done the way that was: worked out every sample for the oscillator's share, with the filter run a few samples at a time for the Pi's sake. - **Cost on the Pi.** Three VCOs a voice at six voices, with audio-rate modulation, is more per voice than anything here. Measure early. - **Which Minimoog.** The oscillator board changed during its run. One is modelled; the others are #4's switches. ## What it does not cover Patch memory, the Memorymoog's cassette interface and its auto-tune, by Ben's word that memory is irrelevant. The Memorymoog's arpeggiator is `engine/arpeggiator.h`. Its chord memory and hold are #11. The Memorymoog Plus's sequencer would be an issue of its own, as #2 and #5 are. Later, perhaps, by Ben's word on #26: things from the Voyager, which he counts as a Minimoog reissued with additions and so allowed, as the OB-X8 is. They would be settings of this instrument, as the SEM family took a few of the OB-X8's. Not now. ## What is already here to build on - `engine/four_pole_filter.h`: four stages with feedback, already the SH-5's ladder. What makes Moog's sound as it does is how it saturates, which is #4. A Moog built clean will sound close to what is here already, so this instrument leans on #4 more than any other. - `engine/analog_vco.h`: sawtooth, pulse and triangle at once from one ramp, with sync, which is the Memorymoog's VCO as recalled. - The Prophet's `voice.h`, for POLY-MOD and for an oscillator that leaves the keyboard and runs slow. - `engine/key_assign.h`, `engine/portamento.h`, `engine/variance.h`, `engine/zones.h`, the shared arpeggiator and effects. ## Provenance - The Memorymoog has a processor and patch memory. Rule 3: no firmware disassembly. Rule 4: none of Moog's programs. - Rule 2: the Minimoog has more emulations than any instrument. None's code may be read for more than how a problem is structured, and nothing lifted. Fidelity is judged against the manuals and recordings. - **The names.** "Moog" and the model names are trademarks that are actively used and defended. Ben said on 2026-10-12 to use Moog's own names for now, so that he can tell what each is, the repository being private; nearly every instrument's name here will have to change before anything is sold, and these with them. So, say, `instruments/minimoog/` and programs named `minimoog`.