FX Tab¶

The FX tab holds Grainulator's post-mix effects chain. Everything on this tab is global — both layers are already summed by the time the signal arrives, so there is no per-layer FX. Signal flows strictly left to right: Master Filter → Compressor → Delay → Reverb.

The master mixing controls — Layer 1 / Layer 2 faders, pans, and Wet/Dry — used to live on FX but were relocated to the GRAIN tab MASTER column in the 2026-04-07 layout update.

Master Filter¶

A single post-mix filter stage applied before the compressor. The filter bypasses itself automatically when Cutoff is wide open (20 kHz) and Drive is 0, so a fully-open setting costs nothing.

Control	Range	Description
`Model`	10 models	Filter topology: Stilson, Microtracker, Krajeski, MusicDSP, Oberheim, Improved, RKSimulation, Hyperion, DaisyLadder, CytomicSVF. Defaults to CytomicSVF. Same bank as the per-layer filter on the GRAIN tab.
`Cutoff`	20 Hz – 20 kHz	Global filter frequency (log-scaled).
`Reso`	0–1	Resonance at cutoff. High values add a singing, whistling character to the full mix.
`Drive`	0–1	Saturation applied alongside the filter. Adds warmth and gentle compression even with cutoff wide open.

Compressor¶

A feed-forward log-domain compressor (Giannoulis / Massberg / Reiss 2012) with stereo-linked peak detection, a fixed 6 dB soft knee, and an optional brickwall limiter. The character is clean and transparent — this is a glue/bus compressor, not a coloration effect. A live gain reduction meter next to the knob grid shows how hard the detector is working. All six continuous knobs read 0–1 on the UI; the ranges in the table are the mapped musical values.

Control	Range	Description
`ON`	on/off	Master bypass for the compressor stage. Click-free. Default on.
`Thresh`	−60 to 0 dB	Level above which gain reduction starts. Default ≈ −3 dB (very light touch).
`Ratio`	1:1 to 20:1	Amount of reduction above the threshold. Default ≈ 4:1.
`Atk`	0.1 – 100 ms (log)	How quickly the envelope follower reacts to peaks. Short attacks catch transients; long attacks let them through for punch.
`Rel`	10 – 1000 ms (log)	How quickly gain recovers after a peak.
`Makeup`	0 – +40 dB	Output gain added after compression to compensate for reduction.
`Mix`	0–1 (dry→wet)	Parallel-compression blend. At 1.0 the signal is fully compressed; lower values blend in the uncompressed signal for NY-style parallel compression. Default 1.0 (fully wet).
`LIM`	on/off	Post-compressor brickwall limiter that hard-clips at ±1.0 (0 dBFS). Default on as a safety net.

The compressor only sees the wet signal; the dry path on the GRAIN tab's Dry/Wet mix skips it, so the unprocessed input is never compressed.

Delay¶

A stereo tape-style delay with independent L/R times, four routing modes, and two time-change behaviors. Feedback can be pushed above unity for self-oscillating runaways, and the infinite-loop toggle turns the delay into a captured loop.

Control	Range	Description
`TimeL` / `TimeR`	5 – 2730 ms	Delay time per channel (log-scaled).
`Link`	on/off	When on, TimeR follows TimeL. Turn off to set stereo offsets manually. Default on.
`Feedback`	0 – 1.25	Amount fed back into the delay line. Values above 1.0 are self-oscillating — use with care.
`Mod Mode`	Tape, Fade	How the delay reacts when its time parameter is changed. Tape re-pitches the tail as the read head moves (classic tape warp). Fade crossfades between old and new positions without pitch shift.
`Mode`	Dual, PingPong, Single, Cascade	Routing of the two internal delay lines. Dual: independent L/R. PingPong: L→R→L bouncing. Single: mono delay duplicated to both channels. Cascade: the two lines are chained in series for longer or more rhythmic echoes.
`Tone`	−1 to +1	Bipolar tone control on the delayed signal. Negative darkens (low-pass), positive brightens (high-pass).
`Sat`	0–1	Saturation drive inside the feedback loop. Adds warmth and iterative grit as feedback regenerates.
`Sync`	on/off	When on, delay times snap to host tempo. Uses `Clock Div` and `Sync Offset`.
`Clock Div`	1/4 – 4/1	Tempo division when `Sync` is on. Available values: 1/4, 1/3, 1/2, 2/3, 3/4, 1/1, 3/2, 2/1, 3/1, 4/1. Default 1/1.
`Sync Offset`	−5 to +5	Integer offset from the selected clock division (steps in the divisor table) for swing and pushed/pulled feel.
`Loop`	on/off	Infinite-loop mode — the current delay buffer is captured and plays back indefinitely regardless of feedback.
`Mix`	0–1	Delay wet/dry blend for the delay stage itself (independent of the global Dry/Wet on GRAIN).

The two mode parameters are not duplicates. Mode is the routing between the two internal delay lines (Dual / PingPong / Single / Cascade). Mod Mode is the time-change behavior: Tape pitches the tail when you turn the time knob, Fade crossfades without pitch shift.

Reverb¶

The reverb panel has an algorithm selector that switches between three distinct reverb engines. The surrounding knobs (Size, Damp, Width, Shimmer, Tone, Mix, Freeze) are shared across all three algorithms — the UI layout never changes — but the underlying interpretation depends on which engine is active.

Algorithm selector¶

The three engines are named for their character, not their internal algorithm. Default is Stormy.

Algorithm	Engine	Character	Best for
`Misty`	Signalsmith Basics	Clean, modern, diffuse. No shimmer, no freeze behavior.	Transparent ambience, pads, realistic-sounding spaces where the reverb should get out of the way.
`Cloudy`	Mutable Rings (Griesinger)	Smooth, classic plate/hall tone with gentle modulation. No shimmer, no freeze behavior.	Warm vintage-style reverb on grain clouds and sustained textures.
`Stormy`	Oliverb (extended Griesinger/Dattorro)	Rich, heavily-modulated, with pitch-shift shimmer in the feedback loop and infinite freeze.	Shimmer pads, ambient tails, evolving textures, long drones. This is the default and the most Grainulator-like.

Common controls¶

Control	Range	Description
`Size`	0–1	Room size / decay length. All three engines scale decay time from this.
`Damp`	0–1	High-frequency damping in the feedback loop. Higher values make tails darker over time.
`Width`	0–1	Stereo width / diffusion. Maps to diffuser AP coefficients inside each engine.
`Shimmer`	0–1	Pitch-shift amount in the reverb feedback loop. Only audible on Stormy — mapped to approximately ±12 semitones around a center-off point. Ignored by Misty and Cloudy.
`Tone`	−100 to +100	Bipolar post-reverb tone shelf. Negative darkens, positive brightens. Common to all engines.
`Mix`	0–1	Reverb wet/dry blend for the reverb stage. Default 0 — reverb is off until you turn it up.
`Freeze`	on/off	Captures the current reverb state and sustains it indefinitely. Only has effect on Stormy: input gain, damping, and high-pass are disabled so the tail holds forever. Misty and Cloudy ignore this toggle.

Notes on per-algorithm behavior¶

Stormy is where the personality lives: nine random modulation LFOs scattered through the topology, a dual-tap pitch shifter per feedback branch, a HP filter to keep long tails clean, and an infinite freeze. Modulation rate and depth scale automatically with Size.
Cloudy is the previous default — the Mutable Rings Griesinger reverb. Smooth and musical, without shimmer or freeze.
Misty is the cleanest of the three; best when you want the reverb to feel like a natural space rather than an effect.
Switching algorithms briefly clears the newly-selected engine's buffers, so you will hear the tail cut on switch.
Shimmer and Freeze remain visible in all modes on purpose — they simply do nothing in Misty and Cloudy.