SYNTH Tab¶

The SYNTH tab in the standalone macOS app

The SYNTH tab gathers the traditional-synthesis elements that sit on top of the granular core: the two Spectral Array Oscillator (SAO) columns — per-layer phase-vocoder synths — a Voice Interaction panel between them for cross-layer routing, a Sub Oscillator, and the VCA and Filter envelopes that shape each played note. The Resonator lives on the SYNTH tab in compact layouts and elsewhere in the desktop layout; see the section below.

Unlike the GRAIN tab — where every knob edits one layer at a time — most of the SYNTH panels drive a single shared engine. The Sub Oscillator, VCA envelope, Filter envelope, and Glide are global: they are mounted in the UI via Layer 1's parameters and any change applies to both layers. The two Spectral columns are genuinely per-layer — Layer 1 and Layer 2 each have an independent Spectral Array Oscillator. Only Root 1 and Root 2 under MIDI are genuinely independent per layer.

Spectral panel (Spectral Array Oscillator)¶

Each layer has its own Spectral Array Oscillator (SAO) column that sits at the head of the SYNTH tab — Layer 1's panel on the left, Layer 2's on the right, with the Voice Interaction panel between them. The SAO is a phase-vocoder-based synth that captures or generates a spectral frame and then re-tunes, re-shapes, and re-pitches it. It is MIDI-responsive and polyphonic — held notes drive multiple voices through a single SAO instance.

Top toggles¶

A row of three toggles runs along the panel header:

Toggle	Behaviour
`ENABLE`	Master power for the Spectral panel. Off bypasses the SAO entirely and consumes no CPU.
`SAO`	Switches between Spectral Array Oscillator mode (synth-style polyphonic re-pitch driven by MIDI) and the simpler frame-pass mode. SAO mode is the default for melodic playing.
`FREEZE`	Captures the current spectral frame and holds it. Useful for sustaining a moment of the source under polyphonic re-pitch.

8-step pitch grid¶

Beneath the toggles, an 8-step pad row displays the SAO's pitch sequence — each cell shows where in the spectral frame the next voice will read. The grid scrolls under polyphonic activity; the active cell is highlighted in the layer's accent color (orange for Layer 1, green for Layer 2). The current center pitch (e.g. A2, G#4) and its frequency are displayed alongside the grid.

Knobs (top row)¶

Three knobs above the FMT toggle shape the spectral frame's pitch and balance:

Control	Range	Description
`Focus`	−1 to +1	Sharpens or softens which partials are emphasised in the spectral frame. Negative values broaden the spectrum; positive values concentrate energy on the strongest partials.
`Transpose`	−24 to +24 st	Pitch offset applied to the entire spectral frame in semitones. Independent of MIDI note tracking.
`Tilt`	−1 to +1	Tilts the spectrum: negative darkens (rolls off highs), positive brightens (rolls off lows).

FMT toggle¶

A FMT — PITCH BOTH segmented toggle sits between the two knob rows. It controls how MIDI notes interact with the spectral frame:

State	Behaviour
`FMT`	Formant-only — incoming notes shift formants without changing fundamental pitch.
`PITCH`	Pitch-only — notes re-pitch the frame without preserving formants.
`BOTH`	Both formant and pitch track the played note. The default — the most "synth-like" behaviour.

Knobs (bottom row)¶

Control	Range	Description
`Clarity`	0–1	Removes noise and softens artifacts in the spectral frame. Higher values produce a cleaner, more pitched tone at the cost of texture.
`Partials`	0–1	Number of harmonic partials retained, as a fraction of the available bins. Lower values produce thinner, more focused tones; higher values include more harmonic detail.
`Scan`	0–1	Position scan through the spectral frame buffer. At 0 the SAO reads the captured frame; turning Scan up sweeps through earlier frames in the buffer for textural movement.

Capture / Clear¶

Two buttons at the bottom of the panel control the spectral frame:

Capture — grabs a snapshot of the live grain output as the new spectral frame. Press while audio is playing through the layer to load fresh material into the SAO.
Clear — wipes the captured frame and returns to silence until the next capture.

The captured frame is per-layer and is saved with the preset.

Voice Interaction panel¶

Sits between the two Spectral columns. Replaces the former MASTER · XMOD panel in v20+. Three knobs drive categorically different cross-voice effects — Follow (time-domain source coupling), Vocode (spectral envelope transfer), and Duck (amplitude sidechain) — governed by a shared direction switch and a power toggle that bypasses the whole section.

An animated bus indicator above the direction switch visualises current effect amount (line thickness) and routing (flow direction of the travelling dots). In Both mode the dots follow whichever layer is louder at the moment.

Direction¶

One 3-state segmented control governs all three knobs:

State	Behaviour
`V1 → V2`	Layer 1 is driver; Layer 2 is follower. All three knobs affect Layer 2 only.
`V1 ↔ V2` (Both)	Mutual / symmetric. Each layer acts on the other with the same knob amounts.
`V2 → V1`	Layer 2 is driver; Layer 1 is follower.

Knobs¶

Control	Range	Description
`Follow`	0–1	The follower layer's granular engine reads the driver's live post-grain audio instead of its own loaded buffer. At 1 the follower is fully tracking the driver's output; at 0 it plays its own buffer (default). The follower's `Position` knob is reinterpreted as ring-buffer age — 0 = newest, 1 = oldest (~2 s back). Grain size, pitch, and speed still work inside the live source. In Both mode, a one-block latency prevents feedback.
`Vocode`	0–1	True spectral vocoding. The driver's mean-normalised spectral envelope multiplies the follower's bin magnitudes. At 1 the follower adopts the driver's timbral/formant contour while keeping its own harmonic content. Loudness-preserving — the mean normalisation stops the follower from getting quiet when the driver is sparse. This replaces the old X-Mod enhancer, which was a subtle per-bin boost; Vocode is categorically different.
`Duck`	−1 to +1	The driver's amplitude envelope modulates the follower's output gain. Negative = classic sidechain duck (follower dips when driver is loud). Positive = "swell" / shadow (follower amplifies with the driver). 0 is bypass. Attack ≈ 3 ms, release ≈ 150 ms, hard-coded in v20. Read from pre-duck envelopes so mutual ducking in Both mode is feedback-safe.

Power toggle¶

The power icon in the panel title stripe hard-bypasses the entire section. Use it to A/B the contribution of Voice Interaction without resetting all three knobs.

Mod routing¶

All three knobs are available as mod destinations under a new Voice FX category on the MOD tab. The direction switch and power toggle are not modulatable (they're discrete state), but their param values round-trip cleanly through preset save/load and DAW automation.

Preset upgrade from v19 and earlier¶

Presets saved in v19 with a non-zero X-Mod value are automatically upgraded on load: Vocode is seeded to max(V1 X-Mod, V2 X-Mod), direction is set to Both, and the section is enabled. The legacy per-layer X-Mod params are retained in the enum as no-ops so old mod-lane routings do not produce errors — their destination menu entry now reads (legacy).

Resonator¶

A global resonant body based on the Mutable Instruments Rings DSP. When Enable is off the resonator is bypassed and consumes no CPU. A small live preview next to the panel visualises the current harmonic structure.

Control	Range	Description
`Enable`	on / off	Bypass the resonator entirely. Default off.
`Polyphony`	1 / 2 / 3 / 4	Number of simultaneous resonator voices. Higher values give richer chords at higher CPU cost.
`Chord`	0–1	Harmonic structure. Sweeps through chord qualities and inharmonicities (internal name: Structure).
`Bright`	0–1	Brightness — the balance of upper partials. Higher values add treble and shimmer.
`Damp`	0–1	Damping / decay time of the resonance. Low = short ping, high = long ring.
`Scatter`	0–1	Modal position / excitation point. Shifts the harmonic balance (internal name: Position).
`Note`	0–127 (MIDI)	Center pitch of the resonator. Displayed as a note name.
`Mix`	0–1	Dry/wet blend between the pre-resonator signal and the resonator output.
`Distort`	0–1	Drive / saturation inside the resonator feedback path.
`Polarity`	Saw / Square	Feedback polarity of the resonator. Saw is positive feedback (softer, vowel-like); Square is negative feedback (hollow, square-wave character).

The Resonator runs post-grain, so its pitch follows the grain material by default. Lower Mix values keep the grains in front; crank it toward 1 to turn the plugin into a pure physical-modelled voice.

Sub Oscillator¶

A global monophonic sub that tracks the played note and thickens the low end. Set Level to 0 to disable.

Control	Range	Description
`Level`	0–1	Output level of the sub. 0 silences it.
`Note`	0–127 (MIDI)	Base pitch of the sub when no MIDI note is playing (Free mode), or the reference pitch in Instrument mode. Displayed as a note name.
`Wave`	Sine / Tri / Saw / Sqr	Oscillator waveform. Sine is pure, Triangle is soft, Saw and Square (both band-limited) add harmonics.
`Octave`	−2 / −1 / 0	Octave offset relative to the played note.

VCA Envelope¶

A global ADSR that shapes the amplitude of every played note. In Instrument play mode the envelope retriggers on each note-on; in Free mode it effectively holds at sustain while the global transport is running.

Control	Range	Default	Description
`A` (Attack)	0.001–3 s	1 ms	Time from note-on to peak level.
`D` (Decay)	0.001–5 s	1 ms	Time from peak down to the sustain level.
`S` (Sustain)	0–1	1.0	Level held while the note is active.
`R` (Release)	0.001–5 s	300 ms	Time to fade to silence after note-off.

Filter Envelope¶

A second ADSR that modulates the per-layer filter cutoff. The filter itself — model, cutoff, resonance, drive — lives on the GRAIN tab FILTER column, along with the bipolar Depth knob that scales how much of this envelope reaches the cutoff.

Control	Range	Default	Description
`A` (Attack)	0.001–3 s	10 ms	Time from note-on to peak envelope level.
`D` (Decay)	0.001–5 s	100 ms	Time from peak to sustain.
`S` (Sustain)	0–1	1.0	Level held while the note is active.
`R` (Release)	0.001–5 s	100 ms	Time to fade after note-off.

With Depth at 0 the envelope has no effect. Push it positive to open the filter on note-on and let it close back toward the static cutoff; push it negative to invert the shape.

MIDI Control¶

Grainulator has two play modes, selected in the header settings popup:

Free — the global transport runs grains continuously; MIDI notes are ignored for pitch.
Instrument — note-on / note-off gate the VCA and filter envelopes, and incoming notes transpose the grain pitch relative to the layer's root note.

The MIDI panel in the SYNTH tab exposes three knobs:

Control	Range	Default	Description
`Root 1`	0–127 (MIDI)	60 (C3)	Root note for Layer 1. When you play this MIDI note in Instrument mode, Layer 1 plays its source at unshifted pitch.
`Root 2`	0–127 (MIDI)	60 (C3)	Root note for Layer 2, independently settable.
`Glide`	0–2 s	0 s	Portamento time between consecutive MIDI notes. Applied to both layers.

Both root-note knobs render their value as a note name (C3, F#4, …) rather than a raw number, matching the Note knobs on the Resonator and Sub panels.

On every MIDI note-on in Instrument mode the engine calculates note − root for each layer and applies that offset on top of the Pitch knob from the GRAIN tab — so Layer 1 and Layer 2 can transpose against the same incoming note by setting different root values. The Resonator tracks the note offset from Layer 1's root as a single global reference.

Glide smooths pitch transitions between notes at the per-layer level; 0 disables portamento, 2 s gives a long, slow slide. It applies equally to both layers.