SYNTH.md

Synth

SwayCommand includes a wavetable synthesizer so a Sway is playable as an instrument without installing a plugin. Audima's downloads page recommends Vital to first-time users ("Vital Synth Pack Free · Best for Beginners") and ships a Sway project for it; this engine targets the same ground.

Implementation: src/renderer/audio/synth.js and the wavetable bank in src/renderer/audio/wavetables.js. The panel lives in the SYNTH drawer (STUDIO.md).

Capability against Vital

Vital feature	SwayCommand	Notes
3 wavetable oscillators	Yes	7 generated tables, continuous morph
Wavetable position morph	Yes	Crossfade between adjacent spectral frames
Unison with detune and stereo spread	Yes	1 to 8 voices per oscillator
Sub oscillator	Yes	sine/triangle/saw/square, −3 to 0 octaves
Noise oscillator	Yes	white or pink
2 filters	Yes	lowpass, highpass, bandpass, notch, with drive and key tracking
3 envelopes	Yes	ADSR; env1 is the amplifier
4 LFOs	Yes	sine, triangle, saw, square
Modulation matrix	Yes	9 sources, 15 destinations, bipolar amount
Effects	Yes	distortion, chorus, phaser, delay, reverb, compressor, 3-band EQ
Presets	7 factory	Init, Super Saw, Deep Bass, Wobble Bass, Glass Pad, Pluck Lead, Formant Vox
Spectral warp modes	No	Vital's warp operates on the table in the spectral domain; here the table generators fix the spectrum
Sample and text-to-wavetable import	No	Tables are generated, not loaded
Wavetable editor	No
MPE	Partial	Pitch bend and mod wheel are handled; per-note expression is not

The gaps are the parts of Vital that need a custom DSP path. createPeriodicWave supplies band-limited harmonic frames, which covers wavetable playback and morphing but not runtime spectral warping.

Wavetables

A Vital table is a series of frames the oscillator morphs between. Web Audio has no wavetable oscillator, but createPeriodicWave takes harmonic amplitudes, which is a frame expressed spectrally. Each table is therefore 8 PeriodicWave frames of up to 64 harmonics, and the morph is a crossfade between the two frames the position falls between, two oscillators per unison voice, gain-blended.

Frames are generated rather than sampled, so the bank costs kilobytes and every frame is band-limited by construction.

Table	Character
basic	Saw to square
harmonic	Sine to saw; harmonics enter one at a time
hollow	Odd harmonics opening to a reedy spectrum
formant	Two moving spectral peaks, vowel-like
bell	Inharmonic-leaning partial clusters
pulse	Pulse-width modulation expressed spectrally
noisy	Deterministic pseudo-random partials

Signal path

osc1 ┐
osc2 ┼─ mix ─ filter1 ─ filter2 ─ ampEnv ─ pan ─┐
osc3 ┤                                          ├─ distortion ─ chorus ─ phaser
sub  ┤                                          │   ─ delay ─ reverb ─ comp ─ EQ ─ master
noise┘                                          ┘

The master output connects to both the speakers and the analyser, so playing the synth drives the visuals exactly as any other audio source does.

Effects are built once and bypassed by mix level rather than rewiring, so changing a patch never clicks.

Modulation

Envelopes are per-voice, scheduled as AudioParam automation at note-on. LFOs are global nodes fanned into per-voice gain stages, which keeps polyphony cheap.

Source	Kind
env2, env3	Per-voice, scheduled at note-on
lfo1-lfo4	Global, live node connection
velocity, keytrack, modwheel	Static, evaluated at note-on

Destinations: oscillator position, level and tune; both filters' cutoff and resonance; amplitude; pan.

Playing it

Input	Behaviour
Sway notes	Note-on and note-off drive the synth, including notes outside the pad range that the Theory Engine sends
Pitch bend	Applies over the patch's bend range, default 2 semitones
CC 1	Mod wheel, available as a matrix source
On-screen keyboard	Seventeen keys from C3 in the SYNTH drawer
Computer keyboard	A W S E D F T G Y H U J K O L P ; while the SYNTH drawer is open; the keys are not captured elsewhere, so the cockpit shortcuts are unaffected

Whether a pad strike also plays the synth is decided by the project's note-routing mode: by default, pads that carry an assignment no longer double-fire the synth, while free pitches (Theory Engine notes outside the pad range) always reach it (STUDIO.md).

theDAW alignment

The module is shaped to lift into theDAW rather than to be rewritten for it.

theDAW interface	Here
VoiceTrigger, (ctx, dest, midi, velocity, when, duration, master)	synth.voiceTrigger() returns a function with that exact signature, so a patch drops into piano-roll preview, offline bounce, init render, and the timeline
VisualControl, { key, label, kind, group, min, max, step }	synth.controlManifest() returns that shape; theDAW's control-sync bus and MIDI mapper consume it without an adapter
Factory-function modules taking ctx and a destination list	createSynth(ctx, destinationNodes), matching sampler.js and audio.js
synthVoiceKit helpers (mtof, distCurve)	Reproduced locally with the same semantics

noteOff accepts a future timestamp and retires its bookkeeping when the release begins, not when it is scheduled, so offline rendering reports voice counts correctly.