`audioImpulse(...)` -- Stochastic Repeating Process

Uses the same pool and selection engine as audioPool, but runs as a continuous autonomous process that keeps firing hits at a configurable rate. Designed for textures, granular clouds, stochastic rhythms, and ambient layers.

Syntax

audioImpulse(path:"sfx/rain", rate:30, jitter:0.4, poly:6, lifetime:region)

Timing Parameters

Key	Default	Description
`rate`	30	Events per minute
`jitter`	0	Timing randomisation 0--1. 0 = steady clock, 1 = fully random spacing

The interval between hits is computed as base = 60 / rate seconds. Jitter widens this: the actual interval is uniformly distributed between base * (1 - jitter) and base * (1 + jitter).

Sound Parameters

Key	Default	Description
`path` (required)	--	Folder inside project audio directory. Paths containing `/` must be quoted
`format`	`wav`	File extension
`mode`	`shuffle`	Selection mode: `shuffle`, `rand`, or `sequential`
`amp`	1	Gain, or `rand(a, b)`
`pan`	0	Stereo position, or `rand(-1, 1)`
`speed`	1	Playback rate, or `rand(a, b)`. Negative = reverse
`speedRandom`	0	Per-hit randomisation range centred on `speed`
`fade`	0	Shorthand for fadeIn + fadeOut
`fadein`	0	Fade-in (beats or percentage)
`fadeout`	0	Fade-out (beats or percentage)
`loop`	1	Loop each hit
`poly`	6	Max simultaneous voices
`uid`	auto	Process identity
`filter`	--	Filter object `{type, freq, q}`
`delay`	--	Delay object `{time, fb, mix}`
`reverb`	--	A room: `{mix, time, damp, pre}` -- see effects
`waveform`	`self`	Waveform display target: `self`, `none`, or element id
`overlay`	2	Overlay detail level: 0/off, 1/brief, 2/expanded

See audio_shared for details on fades, random expressions, effects, waveform display, and OSC output.

Speed and speedRandom

The speed parameter sets the base playback rate for each hit. speedRandom adds per-hit randomisation centred on the base value. For example, speed:1, speedRandom:0.3 produces speeds between 0.7 and 1.3.

Negative speed values play each hit in reverse using a sample-reversed buffer copy.

Following a Signal

rate: and jitter: can follow() (or map()) a signal, and the process takes each new value for its next interval. A rate turned up a long way does not wait out a gap already scheduled at the old rate. amp:, pan: and speed: can follow too: each hit reads the signal as it fires.

audioImpulse(uid:rain, path:drops, rate:follow(adc.amp, 10, 120), speed:map(adc.pitch, 200, 1000, 0.5, 2))

Lifetime Modes

Value	Behaviour
`process`	Runs until explicitly stopped via code or transport

Selection Modes

Impulse supports the same modes as audioPool via the mode parameter. Both use the shared selectFromPool engine:

Mode	Behaviour
`shuffle`	No repeats until pool exhausted, then reshuffle
`rand`	Pure random, repeats possible
`sequential`	Play in directory order, wrap around

Polyphony

The poly parameter limits simultaneous voices. When the limit is reached, new hits are skipped until a voice frees up. This is enforced by counting active keys in window.activeAudioCues that match the impulse uid prefix.

With poly:0, there is no limit.

Multi-Cursor Waveform

Peak Layers

Each active voice draws a coloured waveform contour (upper and lower polylines) layered on top of the base waveform. Colours are assigned automatically from a 12-colour palette. Layers are added when a hit starts and removed when it completes.

Cursors

Each voice gets an independent cursor line that sweeps across the waveform tracking playback position. The cursor colour matches its peak layer colour. Cursors auto-remove when their voice completes.

With poly:6, up to six cursors and six peak layers can be visible simultaneously, creating a dense visual representation of the stochastic texture.

Reverse Display

When speed is negative, the waveform contours (base and all layers) mirror horizontally via SVG transform, and cursors move right-to-left.

Live Console Hot-Update

Running impulse processes can be modified from the live console by retrigering with the same uid. The following parameters update immediately without restarting the process:

Parameter	Behaviour
`rate`	New trigger interval on next timer tick
`jitter`	New jitter range on next timer tick
`poly`	Updated voice limit
`amp`, `pan`, `speed`	Applied to subsequent hits

If path changes, the file pool is rebuilt asynchronously. Hits are suppressed during the rebuild and resume once the new pool is ready.

The waveform info text updates to reflect the new parameter values.

OSC Parameters

Key	Default	Description
`osc`	0	Enable OSC mirroring (1=on)
`oscaddr`	`/oscilla/audio/impulse`	Custom OSC address — with a leading slash it is sent exactly as written

Each hit sends an OSC message with filename, amp, pan, speed, fadeIn, fadeOut as arguments.

Stopping

An impulse process can be stopped by:

Programmatic: stopAudioImpulse(uid) or stopAllAudioImpulses()

On stop, all active voices fade out, all waveform cursors are removed, and all peak layers are cleared.

Examples

// Basic rainfall texture
audioImpulse(path:"sfx/rain", rate:30, jitter:0.5, poly:6, lifetime:region)

// Dense granular cloud
audioImpulse(
  path:"sfx/grain",
  rate:120,
  jitter:0.8,
  amp:rand(0.05, 0.3),
  pan:rand(-1, 1),
  speed:rand(0.2, 4),
  poly:12,
  lifetime:region
)

// Reverse texture cloud
audioImpulse(
  path:"sfx/textures",
  rate:15,
  jitter:0.7,
  speed:-0.8,
  speedRandom:0.3,
  poly:6,
  lifetime:region
)

// Bird sounds with percentage fades and OSC
audioImpulse(
  path:"sfx/birds",
  rate:20,
  jitter:0.6,
  mode:shuffle,
  amp:rand(0.4, 1),
  pan:rand(-1, 1),
  speed:rand(0.1, 2),
  fadein:0.2,
  fadeout:rand("1%", "60%"),
  poly:6,
  lifetime:region,
  uid:birdgroup,
  osc:1,
  oscaddr:"/audio/birds"
)

// Slow, sparse process mode (no region exit)
audioImpulse(path:"sfx/bells", rate:4, jitter:0.9, poly:3, lifetime:process)

audioImpulse(...) -- Stochastic Repeating Process