Strudel Music

Generate music patterns using Strudel.

End-to-end workflow

1. Set up HTML — load the Strudel script tag (see Quick start below)
2. Initialize Strudel — call initStrudel() (with optional prebake for samples)
3. Load samples — if needed, pass a prebake function; await resolution before playing
4. Verify audio plays — test with sound("bd").play() inside a click handler; check console for errors
5. Build pattern — compose with stack(), note(), sound(), etc., triggered by user gesture

Quick start

Load Strudel from unpkg and call initStrudel() to register all functions as globals:

<script src="https://unpkg.com/@strudel/web@1.3.0"></script>
<script>
  initStrudel();
  // note(), sound(), s(), stack(), cat(), hush(), evaluate() etc. are now global
</script>

Play a pattern (must be inside a user-gesture handler):

note('<c a f e>(3,8)').s('sawtooth').lpf(800).room(0.5).play()

Stop all audio:

hush()

Evaluate a code string (like the REPL):

evaluate('note("c a f e").jux(rev)')

AudioContext policy. Always call .play() or evaluate() from a click/tap handler — never on page load.

Core concepts

Mini-notation — compact DSL inside double-quoted strings:

Pattern functions

Sound sources

sound("bd hh sd hh")          // samples or synths by name
note("c4 e4 g4 b4")           // pitch (letter or MIDI)
n("0 1 2 3").sound("piano")   // sample number
s("sawtooth")                 // shorthand for sound()

Built-in synths: sawtooth, square, triangle, sine, white, pink, brown, crackle.

Essential effects and modifiers

.lpf(800)         // low-pass filter
.gain(0.8)        // volume
.room(2)          // reverb
.delay(0.5)       // delay effect
.slow(2)          // half speed
.fast(2)          // double speed
.jux(rev)         // split stereo, apply fn to right
.every(4, rev)    // apply fn every n cycles
.scale("C:minor") // map n values to scale

For the full effects, time modifiers, pattern modifiers, continuous signals, and drum sound tables, see references/api-reference.md.

Constructors

stack(pat1, pat2)   // play in parallel
cat(pat1, pat2)     // one per cycle
seq(pat1, pat2)     // all in one cycle
silence             // nothing

Scales

n("0 2 4 6").scale("C:minor").sound("piano")

Common scales: C:major, A:minor, D:dorian, G:mixolydian, C:minor:pentatonic, F:major:pentatonic.

Tempo

setcps(0.5)   // cycles per second (default)
setcpm(120)   // cycles per minute

Default is 0.5 cps = 120 BPM at 4 events per cycle.

Samples

Built-in synths (sawtooth, triangle, sine, square) work without any sample loading. For real drum sounds and instruments, you need the TidalCycles dirt-samples pack.

Loading samples in a sprinkle

A curated manifest lives at /shared/sprinkles/strudel-music/samples-manifest.json (44 categories / ~223 samples, _base pointing to GitHub raw URLs).

initStrudel({
  prebake: async function() {
    var json = await slicc.readFile('/shared/sprinkles/strudel-music/samples-manifest.json');
    return samples(JSON.parse(json));
  }
});

Validation checkpoints:

1. Await initStrudel({ prebake: ... }) resolution before playing.
2. Test with sound("bd").play() inside a click handler.
3. If silent, check the browser console for fetch or network errors.
4. If the network is unavailable, fall back to built-in synths (sawtooth, sine, etc.).

Loading samples in a standalone page

// GitHub shorthand (fetches full manifest — ~2000 samples)
initStrudel({
  prebake: () => samples('github:tidalcycles/dirt-samples'),
});

Important notes:

• .bank() does NOT work with this setup. Use 808-prefixed names directly: sound("808bd") not sound("bd").bank("RolandTR808").
• Samples are fetched lazily — first play may pause briefly while the WAV downloads from GitHub.

For full details on manifest structure, categories, and adding more samples, see references/api-reference.md.

Example patterns

808 drum groove:

stack(
  sound("808bd*4"),
  sound("[~ cp]*2"),
  sound("808hc*8").gain(0.5),
  sound("[~ 808oh]*4").gain(0.4)
)

Bass + melody + drums:

stack(
  note("[c2 c2 eb2 g1]").s("sawtooth").lpf(600).gain(0.8),
  n("0 2 4 <3 5>").scale("C:minor").s("triangle").room(0.3),
  sound("bd*4, [~ sd]*2, hh*8?").gain(0.7)
)

Melodic arpeggio with filter sweep:

note("<c3 eb3 g3 bb3>(3,8)")
  .s("sawtooth")
  .lpf(sine.range(200, 4000).slow(4))
  .room(0.5)
  .delay(0.25)

More patterns (ambient generative, Euclidean polyrhythm, multi-sample showcase) are in references/api-reference.md.

Using evaluate() for dynamic code

When building a UI where the user types Strudel code:

initStrudel();
// In a click handler:
evaluate(userCode);  // plays the pattern
// To stop:
hush();

The evaluate() function transpiles and runs Strudel syntax (including $: for multiple patterns, mini-notation in double quotes, and all sugar syntax).

Troubleshooting

Audio doesn't play. Ensure .play() or evaluate() is called inside a click/tap handler.

Samples silently skip or never play. Check the browser console for network errors. Confirm initStrudel({ prebake: ... }) resolved before the pattern started.

evaluate() throws a syntax error. Mini-notation strings must use double quotes ("). Check for unbalanced brackets and valid .method() names. Wrap in try/catch to surface the message in your UI.

Sprinkle integration

When the user wants an interactive music UI, delegate to the strudel-music sprinkle scoop. The sprinkle provides a code editor, play/stop controls, pattern presets, and a visualization. See the sprinkle at /shared/sprinkles/strudel-music/strudel-music.shtml.

To install the sprinkle and its samples manifest:

1. Copy sprinkle/strudel-music.shtml to /shared/sprinkles/strudel-music/strudel-music.shtml
2. Copy sprinkle/samples-manifest.json to /shared/sprinkles/strudel-music/samples-manifest.json
3. Run sprinkle open strudel-music

Reference

For deeper API coverage, read /workspace/skills/strudel-music/references/api-reference.md.