3 Beat Workstation

Single-page polyrhythm workstation built with vanilla JS + Tone.js.

Features

• Multi-lane sequencer with add/remove lanes (up to 12).
• Hybrid editing per lane:
  • Circular step editor
  • Compact step grid editor
• Transport controls:
  • Play/Stop
  • BPM
  • Bars (loop length)
  • Swing
  • Panic (kill all voices)
• Lane tools:
  • Mute / Solo
  • Copy / Paste
  • Clear
  • Fill (2/3/4)
  • Invert
  • Rotate left/right
• Humanization and workflow:
  • Step accent cycling (soft/mid/hard)
  • Mutate lane
  • Undo / Redo
• Persistence/export:
  • Autosaved session in localStorage
  • Presets (IndexedDB with localStorage fallback)
  • Session JSON import/export
  • MIDI export

Quick Start

Run from a local web server (not file://):

python -m http.server 8000

Open:

http://localhost:8000

Controls

Mouse / UI

• Click steps to toggle on/off.
• Right-click a step to cycle accent level.
• Use lane toolbar buttons for lane-level operations.

Keyboard

• Space: Play / Stop
• Ctrl/Cmd + Z: Undo
• Ctrl/Cmd + Shift + Z: Redo
• R: Mutate active lane
• C: Copy active lane
• V: Paste to active lane
• 1-9: Select lane by index
• Left/Right: Move active step
• Enter: Toggle active step
• A: Cycle active step accent
• ?: Toggle shortcuts panel

Project Structure

• index.html: App shell and controls.
• styles.css: UI styling, responsive behavior, reduced-motion support.
• app.js: Bootstrap, store/audio/ui wiring.
• statemanager.js: Reducer store, action handling, undo/redo, persistence.
• audioengine.js: Tone.js scheduling, lane audio graph, playback sync.
• uicontroller.js: Rendering, interaction handlers, shortcuts, presets, import/export.
• midiexport.js: MIDI file generation and download.

Notes

• GET /favicon.ico 404 in local server logs is harmless unless you add a favicon file.
• If audio is blocked, ensure:
  • You started from a web server
  • Network access to CDN scripts is available
  • You interact with the page before playback (browser audio policy)

License

Add your preferred license in LICENSE.