Strudel
Reference skill for programming music with Strudel — a JavaScript live-coding environment based on TidalCycles patterns, running in-browser.
Core Concepts
Cycle — the fundamental time unit (~2 seconds at the default 30 cpm).
All events fit within cycles; adding events makes each shorter, not the total longer.
One cycle = one bar of 4/4 at the default tempo.
Pattern — a pure function from time to events.
Everything is a pattern.
Transforming a pattern wraps it; the original is unchanged.
Mini-notation — a DSL written inside "double quotes" (single-line) or `backticks` (multi-line).
Single quotes '...' are plain JS strings and are NOT parsed as patterns.
Chaining — methods chain left-to-right: note("c e g").s("piano").lpf(800).room(0.4).
$: tracks — the REPL syntax for parallel patterns.
Each $: line is an independent stream.
_$: mutes a track.
Outside the REPL, use stack(...).
Quick Start
// First sound
s("bd sd hh cp")
// First note
note("c3 e3 g3 a3").s("piano")
// Stack drum + melody
stack(
s("bd*4, ~ cp ~ cp, hh*8"),
note("<c3 eb3 g3 bb3>/4").s("piano").room(0.4)
)
// Set BPM (default = 120 BPM in 4/4)
setcpm(120 / 4) // cycles per minute = BPM ÷ beats-per-cycle
BPM Quick Reference
setcpm(120 / 4) // 120 BPM, 4/4
setcpm(128 / 4) // house
setcpm(135 / 4) // techno
setcpm(174 / 4) // drum and bass
setCps(140/60/4) // cycles-per-second form
Keyboard Shortcuts (REPL)
| Key |
Action |
Ctrl+Enter |
Evaluate / update pattern |
Ctrl+. |
Stop all patterns |
Reference Files
Pull these when you need detail:
| File |
Contents |
references/mini-notation.md |
Complete DSL syntax — all operators, euclidean, alternation, polyrhythm |
references/pattern-functions.md |
All pattern combinators — time, conditional, random, accumulation, signals, stepwise |
references/sound-sources.md |
Synths, drum banks, GM samples, FM synthesis, samples loading, MIDI/OSC |
references/audio-effects.md |
Full effects chain — filters, ADSR, envelopes, delay, reverb, phaser, distortion, sidechain |
references/tonal.md |
Scale/chord/voicing API, transposition, xenharmonic |
references/recipes.md |
Production idioms — beats, bass, arpeggios, chord progressions, house/techno/D&B/trap |
references/visual-feedback.md |
Visualizers (pianoroll, scope, spectrum, spiral) — what each shows and when to suggest them |
Workflow
- Start with sound — identify what you're building (drum beat, melody, chord progression, full track).
- Reach for the right reference — use the table above.
Most questions hit mini-notation or pattern-functions.
- Layer with
stack() — combine independent streams.
- Automate with signals — use
sine, rand, perlin for LFOs and continuous modulation.
- Add structure — use
every, sometimes, chunk, arrange for variation over time.
- Add visualizers, especially in educational contexts — default to
pianoroll(), scope(), or spectrum() when explaining or teaching.
See references/visual-feedback.md for when each applies.
Common Gotchas
- Mini-notation only parses inside
"..." or `...` — not '...'.
- Adding more events to a pattern makes each event shorter, not the cycle longer.
<a b c> alternates one element per cycle (3 cycles to complete) — the whole pattern isn't faster.delay feedback ≥ 1 creates an infinite loop; keep it < 1.- Reverb
roomsize is expensive to change while running; set it once.
.orbit(n) — each orbit has its own shared delay/reverb bus.
Default orbit = 1.
1---2name: strudel3description: Use when writing, debugging, or explaining Strudel live-coding music patterns — mini-notation syntax, pattern functions (fast/slow/every/off/stack), synth/sample selection, audio effects, scale/chord/voicing API, or EDM production recipes. Triggers: "write a Strudel pattern", "how do I make a bassline in Strudel", "what does .every() do", "strudel drum beat", "strudel chord voicing", any Strudel code question.4---56# Strudel78Reference skill for programming music with [Strudel](https://strudel.cc) — a JavaScript live-coding environment based on TidalCycles patterns, running in-browser.910## Core Concepts1112**Cycle** — the fundamental time unit (~2 seconds at the default 30 cpm).13All events fit within cycles; adding events makes each shorter, not the total longer.14One cycle = one bar of 4/4 at the default tempo.1516**Pattern** — a pure function from time to events.17Everything is a pattern.18Transforming a pattern wraps it; the original is unchanged.1920**Mini-notation** — a DSL written inside `"double quotes"` (single-line) or `` `backticks` `` (multi-line).21Single quotes `'...'` are plain JS strings and are NOT parsed as patterns.2223**Chaining** — methods chain left-to-right: `note("c e g").s("piano").lpf(800).room(0.4)`.2425**`$:` tracks** — the REPL syntax for parallel patterns.26Each `$:` line is an independent stream.27`_$:` mutes a track.28Outside the REPL, use `stack(...)`.2930## Quick Start3132```js33// First sound34s("bd sd hh cp")3536// First note37note("c3 e3 g3 a3").s("piano")3839// Stack drum + melody40stack(41 s("bd*4, ~ cp ~ cp, hh*8"),42 note("<c3 eb3 g3 bb3>/4").s("piano").room(0.4)43)4445// Set BPM (default = 120 BPM in 4/4)46setcpm(120 / 4) // cycles per minute = BPM ÷ beats-per-cycle47```4849## BPM Quick Reference5051```js52setcpm(120 / 4) // 120 BPM, 4/453setcpm(128 / 4) // house54setcpm(135 / 4) // techno55setcpm(174 / 4) // drum and bass56setCps(140/60/4) // cycles-per-second form57```5859## Keyboard Shortcuts (REPL)6061| Key | Action |62| ------------ | ------------------------- |63| `Ctrl+Enter` | Evaluate / update pattern |64| `Ctrl+.` | Stop all patterns |6566## Reference Files6768Pull these when you need detail:6970| File | Contents |71| -------------------------------------------------------------------- | ------------------------------------------------------------------------------------------- |72| [`references/mini-notation.md`](references/mini-notation.md) | Complete DSL syntax — all operators, euclidean, alternation, polyrhythm |73| [`references/pattern-functions.md`](references/pattern-functions.md) | All pattern combinators — time, conditional, random, accumulation, signals, stepwise |74| [`references/sound-sources.md`](references/sound-sources.md) | Synths, drum banks, GM samples, FM synthesis, samples loading, MIDI/OSC |75| [`references/audio-effects.md`](references/audio-effects.md) | Full effects chain — filters, ADSR, envelopes, delay, reverb, phaser, distortion, sidechain |76| [`references/tonal.md`](references/tonal.md) | Scale/chord/voicing API, transposition, xenharmonic |77| [`references/recipes.md`](references/recipes.md) | Production idioms — beats, bass, arpeggios, chord progressions, house/techno/D&B/trap |78| [`references/visual-feedback.md`](references/visual-feedback.md) | Visualizers (pianoroll, scope, spectrum, spiral) — what each shows and when to suggest them |7980## Workflow81821. **Start with sound** — identify what you're building (drum beat, melody, chord progression, full track).832. **Reach for the right reference** — use the table above.84 Most questions hit mini-notation or pattern-functions.853. **Layer with `stack()`** — combine independent streams.864. **Automate with signals** — use `sine`, `rand`, `perlin` for LFOs and continuous modulation.875. **Add structure** — use `every`, `sometimes`, `chunk`, `arrange` for variation over time.886. **Add visualizers, especially in educational contexts** — default to `pianoroll()`, `scope()`, or `spectrum()` when explaining or teaching.89 See `references/visual-feedback.md` for when each applies.9091## Common Gotchas9293- Mini-notation only parses inside `"..."` or `` `...` `` — not `'...'`.94- Adding more events to a pattern makes each event _shorter_, not the cycle longer.95- `<a b c>` alternates one element per cycle (3 cycles to complete) — the whole pattern isn't faster.96- `delay` feedback ≥ 1 creates an infinite loop; keep it < 1.97- Reverb `roomsize` is expensive to change while running; set it once.98- `.orbit(n)` — each orbit has its own shared delay/reverb bus.99 Default orbit = 1.
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