Web App#

The Cosmo PD-101 runs in the browser as a Web Audio AudioWorklet module compiled from Rust (via Wasm).

Opening the Web App#

Navigate to https://cosmo.purraudio.dev or run locally:

cd packages/cosmo-pd101-plugin
bun run dev

Connecting the Synth#

The synth renders via an AudioWorklet -- an off-main-thread audio processor. When you open the app:

1. The app downloads the compiled Wasm binary (~200 KB gzipped).
2. An AudioContext is created and the worklet node is instantiated.
3. All audio rendering happens off the main thread.

Playing with the Computer Keyboard#

The default virtual keyboard maps to a diatonic C major scale:

Press Space to toggle sustain pedal.

Using a Physical MIDI Controller#

The web app supports MIDI via the Web MIDI API.

Synth Panel Layout#

• Phase Lines -- Select algorithms, set pitch/detune, control blend for each line.
• Step Envelope Editor -- Visually edit three 8-step envelopes per line.
• Modulation Matrix -- 7x195 grid to route modulation sources.
• FX Chain -- Six serial effect slots.

Saving and Loading Patches#

• Browser presets: Load demo patches.
• Custom presets: Save to IndexedDB (persists across sessions).
• Export: Download as JSON.
• Import: Load JSON preset or Casio CZ-101 SysEx dump.

Next: DAW Plugin