Live demo (GitHub Pages): https://ncg777.github.io/rhythm-navigator/

Rhythm Navigator is a fast PWA for exploring and sequencing binary/octal/hex rhythms represented as grouped digits. It combines an expressive rhythm generator (with contour analysis and music-theory predicates) with a lightweight multi-track drum sequencer that supports WAV/MIDI export and external MIDI output.

Built with Vue 3, TypeScript, Vite, Pinia, Tailwind, and Tone.js.

• Generate large sets of rhythms in the browser using a Web Worker (the UI stays responsive)
• Filter by shadow-contour isomorphism and several music-theory predicates
• Agglutinate: concatenate compatible segments while maintaining constraints
• Browse a virtualized library and quickly search by grouped digits, base string, or contour
• Analyze any rhythm: contours, density, syncopation metrics, and predicates at a glance
• Sequence rhythms across multiple drum tracks (kick/snare/hat/perc) with per-track controls
• Export audio (WAV), export MIDI, and save/load full projects (JSON)
• Send live MIDI clocked notes to an external device/DAW (Web MIDI where supported)
• Install as a PWA and use it offline

Generator and library

• Modes: binary (1 bit/digit), octal (3 bits/digit), hex (4 bits/digit) — MSB-first per digit
• Length = Numerator × Denominator (digits/beat); total bits = digits × bitsPerDigit
• Shadow-contour isomorphism filter (canonical vs shadow canonical contour under the same invariances)
• Music-theory predicates and oddities:
  • Maximally even (Euclidean)
  • ROP {2,3}, Odd-interval oddity, No antipodal pairs
  • Low entropy (bounded IOI-entropy)
  • No gaps (contiguous non-zero interval-vector bins)
  • Relatively flat (counts near the mean)
  • Ordinal(n) blocks
• Agglutination engine to build longer strings from compatible parts
• The retention probability feature allows you to control the likelihood of retaining individual rhythms during the generation and agglutination processes. This parameter, expressed as a percentage (0-100), introduces probabilistic filtering to the rhythm generation pipeline.
• Virtualized results list with fast search and sorting

Rhythm analysis

• Canonical and shadow canonical contours with selectable invariances:
  • Circular vs linear
  • Rotation invariant
  • Reflection invariant
• Syncopation metrics based on hierarchical metrical weights
• Relations browser (subsets/supersets/overlaps) within the current library

Sequencer

• Multi-track drum layout with track types: kick, snare, hat, perc
• Rhythm Picker modal to assign any generated rhythm to a chosen track
• Per-track controls: name, type, volume, pan, default velocity, velocity randomization
• Per-instrument parameters (distortion pre-gain, filter type/frequency/Q/rolloff, and more)
• Per-track pattern meter editing (numerator/denominator) with digits-per-beat mapping
• Transport: Play/Stop, BPM, loop bars
• Export WAV, Export MIDI, Export/Import project JSON
• MIDI out: enable/disable, select device, choose channel, rescan devices

PWA and performance

• Installable PWA with offline caching
• Web Workers for generation/agglutination avoid blocking the UI
• Virtualized lists and compact data model (RhythmItem) for memory efficiency

1. Generate rhythms

• Open the settings (gear icon). Choose Mode, Numerator, Denominator and optional constraints (onsets min/max, shadow-iso, predicates). Click Generate.

2. Browse and analyze

• Open the Generated Rhythms modal to search, sort, and select a rhythm. Use the details pane to inspect contours, syncopation, and relations.

3. Sequence

• In the sequencer, click a track’s picker button to open the Rhythm Picker and assign a rhythm. Adjust track parameters, BPM, and loop bars; hit Play.

4. Export or integrate

• Export WAV/MIDI from the transport bar. Export a project to JSON, or import a saved JSON to restore everything (BPM, loop bars, tracks, patterns, params).

Prerequisites: Node.js 18+ recommended.

Install dependencies:

npm install

Run in dev mode (opens in browser):

npm run dev

Build for production:

npm run build

Preview the production build:

npm run preview

Type-check and run tests:

npm run typecheck
npm run test

• UI: Vue 3 + Pinia with Tailwind styling
• Audio/MIDI: Tone.js for synthesis/playback; optional Web MIDI output
• Data model: RhythmItem (compact; stores grouped digits, base, onsets, contours, optional meter)
• Workers:
  • src/workers/generate.ts enumerates digits odometer-style and filters batches
  • src/workers/agglutinate.ts builds concatenations subject to the same constraints
• Utilities:
  • Contours: src/utils/contour.ts
  • Predicates: src/utils/predicates.ts
  • Syncopation: src/utils/syncopation.ts
  • Relations (subsets/supersets/overlaps): src/utils/relations.ts
• Sequencer: src/stores/sequencerStore.ts (tracks, synth graph, transport, export)

• No results? Loosen filters (disable shadow-iso/predicates), widen Onsets min/max, increase Max representatives, or reduce total digits.
• Audio doesn’t start? Many browsers require user interaction before audio can play. Click the page or press Play once to unlock audio.
• MIDI not listed? Ensure your browser supports Web MIDI (Chrome/Edge), then enable MIDI in the transport and rescan devices.
• Slow generation? Disable expensive predicates, or narrow the search space (smaller numerator/denominator).