Les Cercles is a web-based generative music sequencer that combines orbital mechanics with physics-based interactions. It creates evolving musical patterns using "planets" that trigger sounds as they cross "gates" in their orbit, alongside a "slingshot" physics engine for chaotic, collision-based textures.
- Polyrhythmic Logic: Create up to 32 "planets," each with independent RPM (speed), velocity, and note assignments.
- Dynamic Gates: Adjust the number of trigger gates (1-32) on the orbit path.
- Transposition: Gates can be assigned individual pitch shifts (transpositions), allowing a single orbiting note to play complex melodic lines.
- Global Controls: Real-time adjustment of global speed, orbit direction (CW/CCW), and master transposition.
- Slingshot Mechanic: Drag and release from the center to launch "orbs" into the arena.
- Collision Modes:
- Circle: Orbs trigger sound when hitting the outer boundary.
- Gates: Orbs trigger sound when crossing gate lines.
- Notes: Orbs trigger sound when colliding with orbiting planets.
- Generative Chaos: Enable orb-to-orb collisions to create evolving, non-repeating rhythmic textures.
- Synth Engine: Built-in polyphonic web audio synthesizer (Triangle wave with lowpass filtering).
- Music Theory: Lock your sequence to various scales (Chromatic, Major, Minor, Pentatonic, Dorian, Lydian, Whole Tone) or create a Custom Scale.
- Web MIDI Support: Route note data to external hardware synthesizers or DAWs via the "MIDI..." dropdown.
- AUDIO: Toggle the audio engine on/off.
- SETTINGS: Open global settings for Root Note, Scale, and JSON Save/Load.
- MIDI: Select a MIDI output device.
- VOL: Master volume control.
- PLAY/PAUSE: Start or stop the sequencer.
- UNDO: Revert the last action (supports up to 20 steps).
- CLEAR: Reset the entire scene.
- SYNC: Synchronize the RPM of all planets to match the first planet.
- EVEN: Evenly space all planets along the orbital path.
- ORB: Toggle the Slingshot/Orb panel.
- CCW/CW: Toggle orbit direction (Switches UI between Light and Dark mode).
- GATES: Set the number of trigger lines (1-32).
- TRANSPOSE: Shift the pitch offset of all gates.
- RND: Randomize the transposition values of current gates.
- SPEED: Global playback speed multiplier (0.1x to 3.0x).
- Initialize: Click the screen to start the AudioContext.
- Add Planets: Use the + button in the bottom planet list to add new notes.
- Edit Planets: Click a planet chip to adjust its specific Note, RPM, and Velocity.
- Launch Orbs: Toggle "ORB" mode, then drag from the center of the circle to slingshot projectiles.
Les Cercles is a standalone web application with zero dependencies.
- Clone the repository.
- Open
index.htmlin any modern web browser.
Copyright (c) 2026 Jerome Potter.
Released under the MIT License.