Separate vocals, music and drums from a recording (/stem-split)
Separate a song or a film's soundtrack into stems (vocals, drums, bass, other) with Demucs, locally, on the Apple GPU when there is one.
/stem-split {file.mp4}
Separate vocals, drums, bass and other. I need a version of the clip with the background music removed and the speech kept, levelled to -16 LUFS, so the upload is not claimed. Keep the original untouched; write the result next to it with a suffix. In Claude Code, paste the prompt as a message, or run /stem-split which does this end to end.
Install
npx skills add fortunto2/solo-factory/stem-splitSteps
- Install the skill into Claude Code with the line above (or all of solo-factory: npx skills add fortunto2/solo-factory --all).
- Run it when: Other people's music must come out of a clip, or a voice needs isolating.
- The skill asks for what it needs and writes its output into the project; read the summary it prints before trusting the files.
Example
Any track becomes vocals.wav, drums.wav, bass.wav, other.wav (44.1 kHz stereo) with Meta’s htdemucs. Nothing is uploaded; the model downloads once.
Tips
- Source and the full instructions: github.com/fortunto2/solo-factory/tree/main/skills/stem-split (v1.0.0).
- Skills are prompts, not programs: read SKILL.md once, then you know exactly what the agent will do.
| works with | Claude Code: Runs as a skill or a prompt in the terminal; can read your files and write the result. |
| skill | npx skills add fortunto2/solo-factory/stem-split · source |
| cost | Free. No API, no key. |
| status | Unverified: written from the technique, not yet run end to end by us. |
| source | solo-factory/skills/stem-split (MIT) |
| license | CC BY 4.0 for the text here; skills are MIT. |
| updated | 2026-11-01 |
| for agents | skill-stem-split.md |
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