FX Mini
Drive, tone, and a delay that knows when to stop.
Audio and MIDI
Browser session
Audio is stopped.
Input · Built-in clip
Don't have a keyboard handy? These are short MIDI clips, not recordings — they play through whichever instrument is loaded, so switching tools re-voices the same part.
FX Mini
Distortion into a tone filter into a feedback delay - the pedalboard starter chain, and the SDK's teaching effect. The same kernel drives the offline batch renderer.
Parameters
Distortion
Tone Filter
Delay
Master
Output · Audio signal
The signal leaving FX Mini, tapped after the output stage. It's a picture of what your speakers are getting.
About
Distortion into a tone filter into a feedback delay - the pedalboard starter chain, and the SDK's teaching effect. The same kernel drives the offline batch renderer.
Take it into your DAW.
Same DSP as this page. The plugin isn't a rebuild — it's the identical kernel from the identical TypeScript source, compiled native instead of to WASM.
Free forever, no account, and playing it in the browser will never ask you for one. VST3 and standalone today; AU and CLAP are on the roadmap.
Every knob, and what it actually does.
Generated from the module's parameter schema — the same source as the web UI, the worklet transport and the VST3 parameter table, so it cannot drift.
| Param | Range | Default | Units | What it does | Automatable |
|---|---|---|---|---|---|
| Distortion | |||||
Drivedistortion.drive | 0 … 1 | 0.35 | — | How hard the input hits the saturation curve. Below about 0.2 it's a clean boost. | Yes |
Dist Mixdistortion.wet | 0 … 1 | 1 | — | Blend of driven signal against clean, so you can keep grit under the dry. | Yes |
| Tone Filter | |||||
Tonetone.cutoff | 200 … 8000 | 2500 | Hz | Low-pass placed after the distortion, where it actually shapes the harmonics. | Yes |
| Delay | |||||
Timedelay.time | 0.02 … 1 | 0.25 | s | Repeat spacing - short enough for slapback, long enough for a real repeat. | Yes |
Feedbackdelay.feedback | 0 … 0.9 | 0.35 | — | How much of each repeat feeds back. Capped at 0.9 so it will sing, not run away. | Yes |
Delay Mixdelay.wet | 0 … 1 | 0.25 | — | Level of the repeats against the dry signal. | Yes |
| Master | |||||
Levelmaster.level | 0 … 1 | 0.9 | — | Final output trim, after every other stage. | Yes |
Parameter paths (filter.cutoff) are what you'll see in your DAW's automation list and in the SDK. Same names everywhere.
How it works.
The chain is distortion into a tone filter into a feedback delay, in that order and with nothing hidden between the stages. The drive stage is a waveshaper with its own wet/dry mix, so you can blend saturated signal under the clean one rather than committing to it.
Tone is a biquad low-pass sweeping 200 Hz to 8 kHz, placed after the distortion because that is where a tone control does the most work - filtering harmonics the drive stage just generated, rather than filtering the input before they exist.
The delay is single-tap with feedback capped at 0.9. That cap is deliberate: the delay will self-oscillate and sing at the top of its range, but it cannot run away and damage your monitoring. This is the same kernel the offline batch renderer uses, so a render matches what you hear here.
It's yours to read and to fork.
Research preview
npx codex clone fx-mini
npm run devThe codex CLI name is proposed, not shipped. That command gives you this module's DSP, schema, presets and UI as a local project — change a number, hear it immediately.
@codex-music/audio-kernels · profiles/fx1-chain.profile.json · ABI scfx_