A Yamaha DX7 in the browser, with the editor the DX7 never had. Six-operator FM, accurate enough to be a port rather than an imitation, plus the multi-timbral model of a TX802/TX816 rack: eight parts, performances, up to 256 voices.
Live demo: https://woutervannifterick.github.io/texed/
- Open the demo and click LET'S PLAY!
- Play with the on-screen keyboard, your QWERTY keys, or Web MIDI
- Load patches from the built-in library, or drag your own
.syxfiles onto the page
See docs/using-texed.md for the full tour, and
docs/hardware-midi.md for driving real hardware over SysEx (?hw).
Dexed plays a single DX7 voice very accurately, but a TX802 patch is eight voices layered, split and routed together, and Dexed has nowhere to put that. Texed models the whole rack, so factory TX802 and TX816 banks load and sound like themselves.
The envelope displays are not drawings. Each curve is produced by replaying the real envelope generator sample by sample, which is why the graph matches what you hear — including the awkward parts, like a rate that stalls or a level that never arrives. The nodes are draggable, so you can edit a stage by pulling it where you want it.
The engine also fixes a set of long-standing inaccuracies in the shared music-synthesizer-for-android code, checked against the DX7 ROM disassembly: keyboard level scaling that was up to 24 dB out at the top of the curve, a velocity response about twice too deep at low velocities, portamento running 5–16× too fast, and modulation sources combining with a maximum where the hardware sums them. Every one is written up with its ROM citation in docs/vs-dexed.md, which doubles as the list for a possible upstream contribution.
Beyond that: hundreds of factory and community banks built in
(docs/patch-library.md), cartridge and single-voice SysEx
import/export, MiniDexed .ini performances, micro-tuning, undo/redo, a session that
survives a reload, and a headless CLI that renders MIDI to WAV
(docs/cli.md).
| DX7 | Dexed | DX7II | TX802 | TX816 | Texed | |
|---|---|---|---|---|---|---|
| Parts (multi-timbral) | 1 | 1 | 2 | 8 | 8 | 8 |
| Loads performances | no | no | yes | yes | yes | yes |
| Polyphony | 16 | 16 | 16 | 16 | 128 | 256 |
| Mark I operator | yes | yes | no | no | yes | yes |
| Mark II operator | no | yes | yes | yes | no | yes |
| Form | keyboard | VST | keyboard | rack | rack | web |
Mark I and Mark II refer to the two operator behaviours in the DX7 family. Texed ships both, plus an OPL-flavoured third engine, selectable from the top bar.
Texed is a TypeScript port of Dexed (Pascal Gauthier and others), which builds on MSFA (Raph Levien / Google, 2012). The DSP is a deliberate line-by-line port; a golden test hashes the rendered output of all 32 algorithms on each engine so a refactor cannot quietly change the sound.
| Path | Contents |
|---|---|
texed-ts/ | The app: React UI, engine and format packages, CLI host, tests |
patches/ | Source .syx banks, packed into the built-in library at build time |
docs/ | User and contributor guides |
Needs Node.js 24+ and pnpm.
cd texed-ts
pnpm install
pnpm dev # dev server, rebuilds the patch library first
pnpm test# unit tests
pnpm build # production build
pnpm cli song.mid --syx bank.syx # headless WAV render, see docs/cli.mdLint with oxlint, format with prettier, typecheck with tsc — pnpm lint, pnpm format,
pnpm typecheck. CI runs all of it plus Playwright on every
push and PR; deploy publishes Pages from master.
Start with docs/architecture.md — it explains why the patch state lives in the AudioWorklet rather than in React, which is the one thing worth knowing before changing anything. Then CONTRIBUTING.md. docs/vs-dexed.md tracks every divergence from Dexed's engine, in both directions, with file and line references into both trees.
GPL v3, inherited from Dexed. Full text in
LICENSE. The bundled .syx data under patches/ is third-party and factory
content — see docs/patch-library.md.
GitHub issues or a pull request.
Wouter van Nifterick