A new instrument: Moog's Opus 3 #55

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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

Opus 3 (1980). 49 keys, every one at once, from a divide-down tone generator, in three sections that can be mixed and panned: strings, at two footages, through a chorus; organ, of several footages with a level each; and brass, through one ladder filter with one contour for all the keys. It has no memory and no presets.

One model, one instrument. It is a string machine with a synthesizer section, which is what the Omni is, and that is the reason it is not put with the Polymoog: the Polymoog articulates every key and the Opus 3 has one filter and one contour for all of them. If a string machine is ever made generic here, this is a candidate to become settings of it; see #36 and #44, which face the same question.

To find out

Low priority. Ben said on 2026-10-12 that he doubts it will be much of a challenge and that he does not care much about it. It stays on the list, last of the five.
Its sections exactly: the footages, what the strings' voicing filter is, whether the organ's footages are drawbars or switches, and what the brass section's filter and contour offer.
How the keys are gated: an envelope for each key, or one for all, in each section.
The chorus: how many lines and at what rates. One figure-true ensemble in engine/ is wanted by #44 and #45 as well.

What is already here to build on

engine/divide_down.h and the Omni's instrument, which is the same shape.
engine/four_pole_filter.h and engine/filter_channel.h for the brass section; the Poly-800's paraphonic routing is one filter under one envelope for every key already.
engine/effects.h's chorus until the ensemble is measured.

Provenance

No processor, no memory, no presets, so rules 3 and 4 have nothing to say.
Rule 2: nothing from an emulator's code.
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/opus3/ and programs named miniopus3.

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 - **Opus 3** (1980). 49 keys, every one at once, from a divide-down tone generator, in three sections that can be mixed and panned: **strings**, at two footages, through a chorus; **organ**, of several footages with a level each; and **brass**, through one ladder filter with one contour for all the keys. It has no memory and no presets. One model, one instrument. It is a string machine with a synthesizer section, which is what the Omni is, and that is the reason it is not put with the Polymoog: the Polymoog articulates every key and the Opus 3 has one filter and one contour for all of them. If a string machine is ever made generic here, this is a candidate to become settings of it; see #36 and #44, which face the same question. ## To find out - **Low priority.** Ben said on 2026-10-12 that he doubts it will be much of a challenge and that he does not care much about it. It stays on the list, last of the five. - **Its sections exactly**: the footages, what the strings' voicing filter is, whether the organ's footages are drawbars or switches, and what the brass section's filter and contour offer. - **How the keys are gated**: an envelope for each key, or one for all, in each section. - **The chorus**: how many lines and at what rates. One figure-true ensemble in `engine/` is wanted by #44 and #45 as well. ## What is already here to build on - `engine/divide_down.h` and the Omni's instrument, which is the same shape. - `engine/four_pole_filter.h` and `engine/filter_channel.h` for the brass section; the Poly-800's paraphonic routing is one filter under one envelope for every key already. - `engine/effects.h`'s chorus until the ensemble is measured. ## Provenance - No processor, no memory, no presets, so rules 3 and 4 have nothing to say. - Rule 2: nothing from an emulator's code. - **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/opus3/` and programs named `miniopus3`.