OP-FREE

A first step into liberating your OP-Z. New synths and effects for the teenage engineering OP-Z, built by the community, that you can try in your browser and load onto your own unit; the SDK to build your own; and the research into how the OP-Z firmware works, as the ground for firmware mods later.

An independent community project. Not affiliated with, endorsed, sponsored or supported by teenage engineering. OP-Z is their product and trademark. This repository contains no OP-Z firmware, no keys, and none of teenage engineering's code, engines or sounds. Provided as is, without warranty: read the risk notice on the site first.

Website: https://mutlisensor.github.io/op-free/

What is here

Folder	What it is
site/	The website: the landing, the synth lab (play every engine in the browser) and the loader (put them on your OP-Z). Static, hosted on GitHub Pages
sdk/	Write your own engine: the engine ABI header, DSP helpers, templates, linker script and the SDK docs
sim/	The host simulator (opzsim): runs any engine on your computer, renders scenarios, checks the ABI rules; also in the browser (sim/web)
tools/	Build, pack, verify, crash and CPU checks, the engine scaffold, and the installer CLI (tools/opz.py, with an offline --fake OP-Z)
core/	The TypeScript core that talks to the OP-Z over USB MIDI (the file service, backups, install plans, safety checks)
engines/	The community synths, drum engines and effects, each with its presets, tests and a one-page manual
research/	How the OP-Z works, with an evidence label on every claim
guides/	Use the site, extract your own firmware, submit an engine, propose a firmware mod
firmware-mods/	Coming soon: the mod format and the builder that applies mods to your own firmware file
ROADMAP.md	The plan and what's next

How engines get onto an OP-Z

Every OP-Z synth and effect is a small DSP module that the OS loads from its storage and calls through a few functions. A new engine ships as a user plug, installed over USB with the same file protocol the official app uses, and sits in a sound slot next to teenage engineering's own. Nothing is flashed, and a restore puts everything back. The site walks you through it: try → pick → connect and back up → install → content mode (presets) → eject and play.

Contributing

New synths and effects are welcome: start with the SDK quickstart, then submit an engine. Firmware mods start as research and proposals: propose a firmware mod. Rules for every contribution are in CONTRIBUTING.md.

Licence

MIT (LICENSE). Engines that port DSP from other projects credit them in their README; only MIT, BSD, ISC or public-domain sources are accepted.