FX

Each FX function wraps a Machine and returns a new Machine with the effect in the signal path.

Usage

Direct form

Pass the machine as the first argument:

const synth = reverb(comp(vasynth({ wave: 'sawtooth' }), { threshold: -20 }), { mix: 0.3 })

chain() helper

Use chain() to apply multiple FX without deep nesting. Call each FX with options only (curried form) to get a (Machine) => Machine transformer:

const synth = chain(
  vasynth({ wave: 'sawtooth' }),
  comp({ threshold: -20, ratio: 4 }),
  reverb({ mix: 0.3 }),
)

chain(machine, ...fxChain) → Machine

Argument	Type	Description
`machine`	`Machine`	Source machine
`...fxChain`	`((m: Machine) => Machine)[]`	FX functions in curried form

Both forms are interchangeable and fully backward-compatible.

Available effects

eq — Parametric EQ

Filters and shapes individual frequency bands.

chain(vasynth(), eq({ type: 'highpass', freq: 80 }))

Parameter	Default	Description
`type`	`'peaking'`	`lowpass` / `highpass` / `bandpass` / `notch` / `peaking` / `lowshelf` / `highshelf`
`freq`	1000	Center / cutoff frequency (Hz)
`gain`	0	Band gain in dB (peaking / shelf only)
`q`	1	Bandwidth / resonance
`mix`	1.0	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

comp — Compressor

Reduces dynamic range for punch and consistency.

chain(vasynth(), comp({ threshold: -24, ratio: 4, makeup: 6 }))

Parameter	Default	Description
`threshold`	-24	Compression threshold (dB)
`ratio`	4	Compression ratio
`attack`	0.003	Attack time (s)
`release`	0.25	Release time (s)
`knee`	6	Knee width (dB)
`makeup`	0	Makeup gain (dB)
`mix`	1.0	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

limit — Hard Limiter

Prevents output from exceeding a ceiling.

chain(vasynth(), limit({ threshold: -3 }))

Parameter	Default	Description
`threshold`	-3	Limiter ceiling (dB)
`release`	0.05	Release time (s)

saturate — Tape Saturation

Adds warmth and harmonic density via tanh soft-clipping.

chain(vasynth(), saturate({ drive: 3, mix: 0.8 }))

Parameter	Default	Description
`drive`	2	Saturation amount (1 = linear, 10 = heavy)
`output`	0.8	Output makeup gain
`mix`	1.0	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

distort — Waveshaper Distortion

Hard-clip waveshaper with tone control.

chain(vasynth(), distort({ drive: 10, tone: 3000 }))

Parameter	Default	Description
`drive`	10	Pre-clip gain
`tone`	5000	Post-clip low-pass cutoff (Hz)
`output`	0.5	Output makeup gain
`mix`	1.0	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

reverb — Reverb

Convolution reverb using a synthetically generated impulse response.

chain(vasynth(), reverb({ size: 0.7, mix: 0.3 }))

Parameter	Default	Description
`size`	0.7	IR length scale (0.1–2)
`decay`	2.0	Decay speed — higher = shorter tail (0.5–10)
`damping`	0.5	High-frequency damping (0 = dark, 1 = bright)
`mix`	0.3	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

pingpong — Ping-Pong Delay

Stereo ping-pong delay that alternates L → R → L.

chain(vasynth(), pingpong({ time: 0.375, feedback: 0.4, mix: 0.4 }))

Parameter	Default	Description
`time`	0.375	Delay time per tap (s)
`feedback`	0.4	Feedback amount (0–0.9)
`mix`	0.4	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

chorus — Chorus

LFO-modulated short delay that thickens the sound.

chain(vasynth(), chorus({ rate: 0.5, depth: 0.5, mix: 0.5 }))

Parameter	Default	Description
`rate`	0.5	LFO rate (Hz)
`depth`	0.5	Modulation depth (0–1)
`delay`	25	Center delay time (ms)
`feedback`	0.2	Feedback amount (0–0.5)
`mix`	0.5	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

flanger — Flanger

Jet-sweep effect using a very short LFO-modulated delay (1–5 ms).

chain(vasynth(), flanger({ rate: 0.3, depth: 0.7, feedback: 0.5 }))

Parameter	Default	Description
`rate`	0.3	LFO rate (Hz)
`depth`	0.7	Modulation depth (0–1)
`delay`	3	Center delay time (ms)
`feedback`	0.5	Feedback amount (0–0.95)
`mix`	0.5	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

phaser — Phaser

Cascaded allpass filters swept by an LFO, creating phase-interference notches.

chain(vasynth(), phaser({ stages: 4, rate: 0.5, centerFreq: 800 }))

Parameter	Default	Description
`rate`	0.5	LFO rate (Hz)
`depth`	0.7	Modulation depth (0–1)
`stages`	4	Number of allpass stages (2 / 4 / 6 / 8)
`feedback`	0.4	Feedback amount (0–0.9)
`centerFreq`	800	Allpass center frequency (Hz)
`mix`	0.5	Wet/dry mix
`env`	—	Envelope sequencer for `mix` modulation

stutter — Rhythmic Gate

Rapidly gates the wet signal to create stuttering repetitions. The gate pattern is scheduled once per cycle via scheduleAutomation.

chain(vasynth(), stutter({ rate: 8, duty: 0.5, mix: 0.8 }))

Parameter	Default	Description
`rate`	8	Gate subdivisions per beat (e.g. 8 = 1/8-beat gate)
`duty`	0.5	Gate open fraction 0–1 (0.5 = 50% on, 50% off)
`mix`	0.8	Wet/dry mix — dry signal passes through unaffected

// 1/16-note stutter with tight gate
chain(lead, stutter({ rate: 16, duty: 0.3, mix: 0.9 }))

// Slow gate on a pad, every half-beat
chain(pad, stutter({ rate: 2, duty: 0.6, mix: 0.7 }))

freeze — Feedback Freeze

High-feedback delay loop that sustains the signal, approximating a freeze/hold effect. Useful for ambient drones and glitchy sustain tails.

chain(pad, freeze({ feedback: 0.92, loopTime: 0.4, mix: 0.7 }))

Parameter	Default	Description
`feedback`	0.92	Feedback amount 0–0.999 (higher = longer sustain)
`loopTime`	0.4	Feedback loop length in seconds
`mix`	0.7	Wet/dry mix

// Long ambient drone tail
chain(strings({ attack: 1.2, gain: 0.3 }), freeze({ feedback: 0.97, loopTime: 0.6 }))

// Short glitchy freeze burst
chain(vasynth(), freeze({ feedback: 0.85, loopTime: 0.1, mix: 0.5 }))