Strudel-AI-music/agentic_workflow/syntax.md

Strudel Syntax Reference

Complete reference for the Strudel live coding language (strudel.cc).

1. Tempo & Timing

setcps(BPM/60/4)    // cycles per second — PREFERRED method
setcpm(BPM/4)       // cycles per minute — alternative
// Default: 0.5 cps = 120 BPM = 1 cycle every 2 seconds

BPM to CPS conversion: cps = BPM / 60 / 4 (assuming 4 beats per cycle).

2. Mini-Notation (Pattern Language)

Used inside quotes in functions like sound("..."), note("..."), n("...").

Sequencing

Syntax	Meaning	Example
a b c	Sequence (space-separated)	sound("bd sd hh")
[a b]	Sub-sequence (squish into parent slot)	sound("bd [hh hh] sd hh")
a , b	Play in parallel (polyrhythm)	sound("bd sd, hh*4")
< a b >	Alternate: one per cycle	sound("<bd sd hh>")
~ or -	Rest / silence	sound("bd ~ sd ~")

Speed & Duration

Syntax	Meaning	Example
a*N	Repeat N times (speed up)	sound("hh*16") — 16 hi-hats per cycle
a/N	Slow down by factor N	note("[c e g b]/2") — over 2 cycles
a@N	Elongate: take N time units	note("c@3 e") — c is 3/4, e is 1/4
a!N	Replicate N times (copy)	note("c!3 e") — c c c e

Sample Selection

Syntax	Meaning	Example
name:N	Sample number N	sound("bd:0 bd:1 bd:2")

Advanced Mini-Notation

Syntax	Meaning	Example
a?	50% chance of playing	sound("hh hh? hh hh?")
a?0.3	30% chance of playing	sound("hh?0.3")
{a b c}%N	Euclidean rhythm	sound("{bd bd bd}%8")

3. Core Functions

Sound Sources

sound("bd sd hh cp")           // play samples by name (alias: s)
note("c3 e3 g3 b3")           // play pitched notes (letter or MIDI number)
n("0 2 4 6")                  // play by index (useful with .scale())

Sound Selection

.sound("piano")                // set instrument/sample
.s("piano")                    // shorthand for .sound()
.bank("RolandTR909")          // select drum machine bank
.n("0 1 2 3")                 // sample number within a sound

Drum Sound Names

bd (bass drum), sd (snare), hh (hi-hat closed), oh (open hi-hat), cp (clap), rim (rimshot), lt (low tom), mt (mid tom), ht (high tom), rd (ride), cr (crash)

Drum Machine Banks

RolandTR808, RolandTR909, RolandTR707, RolandTR505, RolandCompurhythm1000, AkaiLinn, RhythmAce, ViscoSpaceDrum, CasioRZ1

Synth Waveforms (use as sound name)

sawtooth, square, triangle, sine, white, pink, brown

GM Instrument Sounds (selection)

piano, gm_electric_guitar_muted, gm_acoustic_bass, gm_synth_bass_1, gm_synth_bass_2, gm_voice_oohs, gm_blown_bottle, gm_synth_strings_1, gm_synth_strings_2, gm_xylophone, gm_accordion, gm_electric_piano_1

4. Effects

Filter

.lpf(800)            // low-pass filter cutoff in Hz
.hpf(200)            // high-pass filter cutoff in Hz
.bpf(1000)           // band-pass filter
.lpq(5)              // filter resonance (Q) — higher = more resonant
.vowel("a e i o")    // vowel formant filter

Amplitude

.gain(0.8)           // volume 0-1+
.velocity(0.7)       // MIDI-style velocity

Envelope (ADSR)

.attack(0.1)         // fade in time (seconds)
.decay(0.2)          // fade to sustain time
.sustain(0.5)        // sustain level 0-1
.release(0.3)        // fade out time after note ends
.adsr(".1:.2:.5:.3") // shorthand: attack:decay:sustain:release

Space

.room(0.5)           // reverb amount 0-1+
.size(0.9)           // reverb room size 0-1
.delay(0.5)          // delay amount 0-1
.delaytime(0.25)     // delay time in seconds (or pattern)
.delayfeedback(0.5)  // delay feedback 0-1
.pan(0.5)            // stereo position 0=left, 0.5=center, 1=right

Playback

.speed(2)            // playback speed (negative = reverse)
.begin(0.25)         // start position in sample 0-1
.end(0.75)           // end position in sample 0-1
.cut(1)              // cut group — stops previous sound in same group
.loop(1)             // loop the sample

Distortion & Character

.distort(0.5)        // distortion amount
.crush(8)            // bit crush (lower = crunchier)
.coarse(8)           // sample rate reduction
.shape(0.5)          // waveshaping distortion

5. Signals (Continuous Modulation)

Signals produce smooth continuous values for automating parameters.

sine                 // smooth wave 0-1
saw                  // ramp up 0-1
tri                  // triangle 0-1
square               // on/off 0-1
cosine               // cosine wave 0-1
rand                 // random values
perlin               // smooth random (Perlin noise)

Signal Modifiers

sine.range(200, 2000)      // remap to range
sine.range(200, 2000).slow(4)  // slow down the LFO
sine.range(200, 2000).fast(2)  // speed up the LFO
sine.segment(8)            // quantize to 8 steps

Usage

.lpf(sine.range(300, 3000).slow(4))   // sweeping filter
.gain(sine.range(0.2, 0.8))           // pulsing volume
.pan(sine.range(0, 1).slow(2))        // auto-pan

6. Pattern Manipulation Functions

Time

.fast(2)             // speed up pattern 2x
.slow(2)             // slow down pattern 2x
.early(0.25)         // shift pattern earlier by 1/4 cycle
.late(0.25)          // shift pattern later

Structural

.rev()               // reverse the pattern
.palindrome()        // play forward then backward
.ply(2)              // repeat each event N times
.chop(8)             // chop each sample into N pieces
.striate(8)          // similar to chop but interleaved

Conditional

.every(4, x => x.rev())           // apply every 4th cycle
.every(3, x => x.fast(2))         // double speed every 3rd cycle
.sometimes(x => x.speed(2))       // 50% chance
.sometimesBy(0.3, x => x.rev())   // 30% chance
.when(x => x % 2 === 0, x => x.rev())  // conditional

Combination

.jux(rev)            // play original left, modified right
.off(1/8, x => x.add(7))   // offset copy + modify
.add(2)              // add to note values
.sub(1)              // subtract from note values

Stacking Patterns

// Method 1: $: prefix (PREFERRED for multi-pattern)
$: sound("bd sd")
$: note("c3 e3 g3")

// Method 2: stack() function (single expression)
stack(
  sound("bd sd"),
  note("c3 e3 g3")
)

// Method 3: comma in mini-notation (within one function)
sound("bd sd, hh*8")

7. Scales & Tonal System

n("0 2 4 6").scale("C:minor")           // scale degrees
n("0 2 4 6").scale("C4:minor")          // with octave
n("0 2 4 6").scale("<C:minor D:dorian>/4") // changing scales

Available Scales

major, minor, dorian, phrygian, lydian, mixolydian, locrian, minor:pentatonic, major:pentatonic, blues, chromatic, harmonicMinor, melodicMinor, whole, diminished

Voicings (Chord Shorthand)

voicing("<Cm7 Fm7 G7 Cm7>").sound("piano")

8. Sample Loading

samples('github:tidalcycles/dirt-samples')   // load from GitHub
samples({ mySound: ['url1.wav', 'url2.wav'] }) // custom

9. Muting & Soloing

$: sound("bd sd")      // playing
_$: sound("hh*8")      // muted (prefix with _)
// .hush()              // append to mute one pattern
// hush()               // global mute

10. Variables & JavaScript

Strudel is JavaScript — you can use variables, functions, arrays:

const drums = s("bd sd [~ bd] sd").bank("RolandTR909")
const hats = s("hh*8").bank("RolandTR909").gain(0.3)
const bass = note("c2 ~ c2 ~ eb2 ~ g1 ~").sound("sawtooth").lpf(600)

$: drums
$: hats
$: bass