A new instrument: Korg's PS family (PS-3100, PS-3200, PS-3300) #24

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opened 2026-10-12 03:07:39 +00:00 by bcox · 0 comments

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2026-10-12 03:07:39 +00:00

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Korg's PS polyphonic synthesizers as a new instrument: the PS-3100, the PS-3200 and the PS-3300. Not started.

Everything below is from recollection, with nothing read. Find and read Korg's owner's and service manuals before designing anything, and put them in docs/references.md.

The instruments, as recalled

The idea. Every key sounds at once. Twelve tone generators, one for each note of the octave, are divided down for the octaves, as the Poly-800's oscillators are; and then each key has a filter, an envelope and an amplifier of its own, so it is fully polyphonic and not paraphonic. 48 keys. Those 48 are all set by the one panel: one cutoff, one resonance and one set of envelope times for every key, not a setting for each as the SEM family's voices have.
PS-3100 (1977). One such section: a waveform switch (triangle, sawtooth, pulses, with pulse width modulation) and a footage, a low-pass with resonance for each key, an envelope for each key, two modulation generators, noise, a sample and hold, a general envelope for the whole instrument, and a patch panel. Twelve small knobs tune each note of the octave, for other temperaments. After the keys are summed: three resonators, band-pass peaks that can be moved by a modulation generator, and an ensemble.
PS-3300 (1977). Three PS-3100 sections under one keyboard, each with its own tone generators, filters, envelopes and resonators, and a mixer for the three: 144 voices of everything.
PS-3200 (1978). Two tone generator banks into one filter and envelope for each key, sixteen memories, and a graphic equalizer where the others have resonators.

To settle with the owner first

One instrument, most likely: a section, and one to three of them, with the PS-3200's second bank and equalizer as settings. The SEM family's sounds are the same shape as the PS-3300's three sections.
The patch panel, which goes with #7 as the ARP 2600's (#22) and the MS-20's do.
Its name, and its programs' names.

What it needs that is not here yet

Cost. A filter and an envelope for each of 48 keys, three times over on the PS-3300, is far past the 32 voices any instrument here has, and thirty-two SEM voices already take half a core of the Pi 3B. Keys that are not down need not be rendered, but a release on every key is the instrument's sound. Measure early, and expect a limit on how many keys sound.
Twelve tone generators shared by every octave, so that octaves are locked in phase and a key has no oscillator to start. instruments/poly800/oscillator.h makes four octaves of squares from one counter; this wants other waveforms too.
The resonators: three band-pass filters after the sum, which engine/state_variable_filter.h could be.
Tuning for each note of the octave. engine/pitch.h knows equal temperament alone.
An ensemble, which is not engine/effects.h's chorus, and a graphic equalizer for the PS-3200.

What is already here to build on

instruments/poly800/ for the divide-down oscillator and engine/polyblep.h; engine/filter_channel.h, a filter with its envelope and the key it tracks.
The SEM family's sounds and each side's own effects, for the PS-3300's sections.
engine/noise.h, the SH-5's sample and hold, the shared arpeggiator and effects.
instruments/README.md says what an instrument must provide.

Provenance

Rule 3: no firmware disassembly and nothing extracted from a ROM. Timings and curves come from the manuals or from measuring a real instrument's audio, or are placeholders.
Rule 4: no factory patches. Reading a user's own dump at run time is allowed.
Rule 2: emulations exist. None's code may be read for more than how a problem is structured, and nothing lifted.
The names are trademarks, which matters for the programs' names and anything sold.

Korg's PS polyphonic synthesizers as a new instrument: the PS-3100, the PS-3200 and the PS-3300. Not started. Everything below is from recollection, with nothing read. **Find and read Korg's owner's and service manuals before designing anything**, and put them in `docs/references.md`. ## The instruments, as recalled - **The idea.** Every key sounds at once. Twelve tone generators, one for each note of the octave, are divided down for the octaves, as the Poly-800's oscillators are; and then **each key has a filter, an envelope and an amplifier of its own**, so it is fully polyphonic and not paraphonic. 48 keys. Those 48 are all set by the one panel: one cutoff, one resonance and one set of envelope times for every key, not a setting for each as the SEM family's voices have. - **PS-3100** (1977). One such section: a waveform switch (triangle, sawtooth, pulses, with pulse width modulation) and a footage, a low-pass with resonance for each key, an envelope for each key, two modulation generators, noise, a sample and hold, a general envelope for the whole instrument, and a patch panel. Twelve small knobs tune each note of the octave, for other temperaments. After the keys are summed: three **resonators**, band-pass peaks that can be moved by a modulation generator, and an ensemble. - **PS-3300** (1977). Three PS-3100 sections under one keyboard, each with its own tone generators, filters, envelopes and resonators, and a mixer for the three: 144 voices of everything. - **PS-3200** (1978). Two tone generator banks into one filter and envelope for each key, sixteen memories, and a graphic equalizer where the others have resonators. ## To settle with the owner first - **One instrument**, most likely: a section, and one to three of them, with the PS-3200's second bank and equalizer as settings. The SEM family's sounds are the same shape as the PS-3300's three sections. - **The patch panel**, which goes with #7 as the ARP 2600's (#22) and the MS-20's do. - **Its name**, and its programs' names. ## What it needs that is not here yet - **Cost.** A filter and an envelope for each of 48 keys, three times over on the PS-3300, is far past the 32 voices any instrument here has, and thirty-two SEM voices already take half a core of the Pi 3B. Keys that are not down need not be rendered, but a release on every key is the instrument's sound. Measure early, and expect a limit on how many keys sound. - **Twelve tone generators shared by every octave**, so that octaves are locked in phase and a key has no oscillator to start. `instruments/poly800/oscillator.h` makes four octaves of squares from one counter; this wants other waveforms too. - **The resonators**: three band-pass filters after the sum, which `engine/state_variable_filter.h` could be. - **Tuning for each note of the octave.** `engine/pitch.h` knows equal temperament alone. - **An ensemble**, which is not `engine/effects.h`'s chorus, and a graphic equalizer for the PS-3200. ## What is already here to build on - `instruments/poly800/` for the divide-down oscillator and `engine/polyblep.h`; `engine/filter_channel.h`, a filter with its envelope and the key it tracks. - The SEM family's sounds and each side's own effects, for the PS-3300's sections. - `engine/noise.h`, the SH-5's sample and hold, the shared arpeggiator and effects. - `instruments/README.md` says what an instrument must provide. ## Provenance - Rule 3: no firmware disassembly and nothing extracted from a ROM. Timings and curves come from the manuals or from measuring a real instrument's audio, or are placeholders. - Rule 4: no factory patches. Reading a user's own dump at run time is allowed. - Rule 2: emulations exist. None's code may be read for more than how a problem is structured, and nothing lifted. - The names are trademarks, which matters for the programs' names and anything sold.