Note: Still Alpha Status: SuperSonic is in active development. The API may continue to evolve, but the core synthesis engine is solid and ready for experimentation. Feedback and ideas are most welcome.

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Back in the late 90s James McCartney designed a series of live audio programming environments called SuperCollider. These were systems with both programming languages and audio runtimes carefully designed for live realtime modification at every level - from high sweeping programming language abstractions all the way down to the fine control of the low-level synthesis components of the audio chain.

One of the many gifts from this work is scsynth - the core synthesis engine James created for version 3 of SuperCollider. It was at this point when he formally separated the language from the synth engine.

This split made it possible to combine scsynth's powerful audio synthesis capabilities with any existing - or yet to exist - programming language.

This then led to a suite of powerful new live coding languages using scsynth for audio synthesis.

What if you didn't just bring your language to scsynth? What if you brought scsynth to your environment?

This is SuperSonic. All the synthesis power of scsynth - rearchitected to reach new places.

Welcome to SuperSonic

SuperSonic is a reworking of SuperCollider's audio synthesis engine scsynth designed to run in new places - in the browser as an AudioWorklet, as a standalone native backend using JUCE, or embedded directly into the BEAM via a NIF. Currently it has the following features:

Core

• scsynth compatible - full OSC command compatibility with SuperCollider's scsynth. See the command reference.
• Malloc-free audio path - zero allocation or blocking on the audio thread.
• Pre-scheduler - dynamically growing holding bay for future OSC bundles with cancellation support.
• Cold-swap recovery - multiple restart levels with automatic synthdef and buffer restoration.
• Upstream compatible - kept in sync with the official SuperCollider scsynth server.
• Tested - 1400+ tests across web, native and NIF targets.

Web

• Dual transport - SharedArrayBuffer for performance, postMessage for zero-config CDN deployment.
• Mobile resilient - suspend, resume and worklet death detection with automatic state restoration.
• Observable - real-time telemetry: ring buffer usage, scheduler depth, audio health and glitch detection.
• Multiple clients - give any Web Worker its own OscChannel to the AudioWorklet with automatic pre-scheduler routing for far-future events. Each channel carries a source ID visible in the aggregated OSC log.
• Hosted on npm - available as supersonic-scsynth with separate packages for core, synthdefs and samples.

Native

• Live device and driver switching - hot-swap at runtime with automatic cold swap on rate mismatch.
• Headless mode - high-resolution timer-driven processing for CI and containers.
• UDP OSC server - drop-in scsynth replacement with /supersonic/* device and recording commands.

NIF

• BEAM embedded - clean OSC binary interface. Same protocol boundary as web and native.
• Dirty scheduler aware - engine init never blocks normal BEAM schedulers.
• PID-based notifications - receive OSC replies and debug output asynchronously via enif_send().

Demo

Try the live demo: sonic-pi.net/supersonic/demo.html

Getting Started

Web

SuperSonic can be fetched remotely via CDN, locally via npm or self-built — see Installation.

Native

Build the standalone backend with scripts/build-native.sh — see Building from Source.

NIF

Build the BEAM NIF with scripts/build-nif.sh — see Building from Source.

For the full list of configuration options, see the API Reference. For installation options see the Installation Guide. Once installed, head to the Quick Start to make your first sound.

Documentation

• Installation - CDN, npm, self-hosting, browser requirements
• Quick Start - Boot and play your first synth
• API Reference - Methods, callbacks, and configuration
• Communication Modes - SAB vs postMessage, server configuration
• scsynth Command Reference - OSC commands for controlling scsynth
• Workers Guide - Send OSC directly from Web Workers and AudioWorklets for the lowest latency.
• Metrics - Performance monitoring and debugging
• Building from Source - WASM, native (JUCE), and NIF (Erlang/Elixir) builds

Support

SuperSonic is brought to you by Sam Aaron. Please consider joining the community of supporters enabling Sam's work on creative coding projects like this, Sonic Pi and Tau5.

• Patreon
• GitHub Sponsors

License

See LICENSE for details.

SuperSonic's GPL-licensed core audio engine (derived from SuperCollider's scsynth) is cleanly separated from MIT-licensed client code on every platform. All communication crosses an OSC protocol boundary — it’s the same protocol and the same message boundary as sending OSC over UDP. The two components are distinct and independent pieces of software that exchange messages through a well-defined protocol interface.

| Platform | GPL engine | MIT client | Boundary | | -------- | ---------- | ---------- | -------- | | Web | WASM + AudioWorklet (supersonic-scsynth-core) | JS API (supersonic-scsynth) | postMessage / SharedArrayBuffer ring buffers | | Native | Standalone executable | N/A (UDP OSC) | Network socket | | NIF | Shared library | Erlang module (src/nif/supersonic.erl) | NIF call passing opaque OSC binaries |

Your application code interacts only with the MIT-licensed client APIs and is not intended to be a derivative work of the GPL components.

Native server note: The native executable and NIF shared library contain both SuperCollider-derived code (GPL) and JUCE (GPL). The resulting binaries are GPL-3.0-or-later and any application that embeds or links them is also subject to the GPL.

Web bundler note: This isolation depends on the GPL code remaining a separate package loaded at runtime. If supersonic-scsynth-core is bundled into your application by a JavaScript bundler (webpack, Rollup, esbuild, etc.), the result is a single combined work and the GPL applies to the entire bundle.

npm packages:

| Package | License | Contains | | ------------------------------ | ---------------- | ------------------------- | | supersonic-scsynth | MIT | JS client API + workers | | supersonic-scsynth-core | GPL-3.0-or-later | WASM engine + AudioWorklet| | supersonic-scsynth-synthdefs | MIT | Synth definitions | | supersonic-scsynth-samples | CC0 | Audio samples |

Credits

Based on SuperCollider by James McCartney and the SuperCollider community. This AudioWorklet port was inspired by Hanns Holger Rutz who started the first port of scsynth to WASM and Dennis Scheiba who continued this work. Thank you to everyone in the SuperCollider community!