VA oscillator shape morphs the modeled instruments have: Korg's saw and triangle toward an octave up, Roland's triangle mod and thin saw #157

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opened 2026-10-06 16:24:13 +00:00 by bcox · 0 comments

bcox commented

2026-10-06 16:24:13 +00:00

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bcox asked on 2026-10-06 for a ticket for each gap docs/feature-survey.md names without one, whether or not it is ever done. Engine claims are from reading the tree at 6a3fede9 on main. Instrument claims are from that document's research, read from the manuals by research agents and not re-checked; the sources are listed there. Nothing here is built, measured or listened to.

Summary

The VA oscillator's shaping controls are the variable shape (the Voyager's morph), the saw's chop and edge time, the pulse width, and the mix of six waves. The MS2000's saw control morphs it toward "a sawtooth wave one octave higher" and its triangle toward "a pitch that is one octave and a fifth higher"; the JP-8000's TRIANGLE MOD is "similar to applying an HPF to a square wave" and its saw SHAPE thins the saw "as though an HPF were applied"; the Virus's Classic shape sweeps a spectral wave through saw to pulse. The thin saw is two saws a phase apart with opposite levels here, the triangle mod approximately the shaper's fold on a triangle, and the Korg morphs have no route.

What the tree has

VaShape::kVariable with VaMorphOrder, VaChop, chop_width, edge_time, VaMixWave, and start phase per oscillator.

The work, as a sketch

A shape-control lane on the saw and triangle that folds or offsets the phase toward the upper octave, which is the phase-shaping family #142 names; this ticket is the instrument-named cases.

Open

What the Korg controls are internally, which the manual does not say.

bcox asked on 2026-10-06 for a ticket for each gap `docs/feature-survey.md` names without one, whether or not it is ever done. Engine claims are from reading the tree at `6a3fede9` on `main`. Instrument claims are from that document's research, read from the manuals by research agents and not re-checked; the sources are listed there. **Nothing here is built, measured or listened to.** ## Summary The VA oscillator's shaping controls are the variable shape (the Voyager's morph), the saw's chop and edge time, the pulse width, and the mix of six waves. The MS2000's saw control morphs it toward "a sawtooth wave one octave higher" and its triangle toward "a pitch that is one octave and a fifth higher"; the JP-8000's TRIANGLE MOD is "similar to applying an HPF to a square wave" and its saw SHAPE thins the saw "as though an HPF were applied"; the Virus's Classic shape sweeps a spectral wave through saw to pulse. The thin saw is two saws a phase apart with opposite levels here, the triangle mod approximately the shaper's fold on a triangle, and the Korg morphs have no route. ## What the tree has - `VaShape::kVariable` with `VaMorphOrder`, `VaChop`, `chop_width`, `edge_time`, `VaMixWave`, and start phase per oscillator. ## The work, as a sketch - A shape-control lane on the saw and triangle that folds or offsets the phase toward the upper octave, which is the phase-shaping family #142 names; this ticket is the instrument-named cases. ## Open What the Korg controls are internally, which the manual does not say.