song-to-ableton git:20260925.2eb4071A

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---
name: song-to-ableton
description: Use when an existing song should be analysed and then rebuilt, covered or reinterpreted in Ableton Live end to end, or when it is unclear whether the user wants the analysis, the Live build, or both.
---

# Song → Ableton (end-to-end orchestrator)

```
  existing audio ──▶  A. ANALYSIS                      ──▶  C. HANDOFF      ──▶  B. ABLETON (MCP)
                      stems · bars/BPM/key · chords          bars + chords +      build/reinterpret:
                      · bass MIDI · lyrics · drum read        drum logic           tempo · clips · MIDI
                                                                                   · devices · scenes · mix
```

**ASK FIRST:** "Do you want song analysis, Ableton building, or both?" Then route only
to what's needed.

> **GOLDEN RULE: reason in BARS, never seconds.** Every length and position is a bar
> count (1, 2, 4, 8, 16, 32…). Convert any "first 16 seconds" to bars and stay in bars.

## Routing

| Need | Skill |
|---|---|
| Analyze the recording (tempo/bars, stems, chords, lyrics, drum read, chart) | `song-analysis` |
| Drive Live — tracks, clips, notes, devices, mixing; connection issues | `ableton-mcp` |
| Arrangement craft — sections, bass/drum patterns, FX chains, dynamics | `ableton-arrangement` |
| The user plays bass (or another mono instrument) and wants it as MIDI | `bass-transcribe` |

## The handoff (analysis output → Ableton input)

| Analysis output | Use in Ableton |
|---|---|
| `pulse_bpm`, `pulse_unit`, `beats_per_bar`, `num_bars` | `set_tempo(pulse_bpm × 4 / pulse_unit)` — Live's tempo counts quarter notes. One bar = `beats_per_bar × 4 / pulse_unit` Live beats (4/4 → 4, 7/8 → 3.5, 11/8 → 5.5); size clips in whole bars |
| `chord_proposal` per `(bar, cell)` | chord clips on a synth/keys track, or a chart for a live band |
| `bar_bpm`, `tempo_drift_pct` | above ~±3% drift, place notes through the beat grid, not one BPM (`ableton-mcp` → "Timing") |
| bass MIDI (root line) | reference clip — or **leave the bass slot empty** for a live bassist |
| drum-pattern read | match the original's kick/snare logic (or `generate_drum_pattern`); never impose a rock backbeat on a non-rock song |
| key/mode | scale + voicings (mind major-triads-under-minor-melody — Trap 2 in `song-analysis`) |
| section map | scenes (jam) or arrangement sections; mirror parallel sections |

**Reinterpreting in a new genre:** keep the **harmonic + rhythmic skeleton** (chords per
bar, original drum logic, section lengths) from analysis; change instrumentation and
energy in Ableton. Analysis says *what the song is*; the build decides *how it sounds*.

## Quickstart

1. Drop `<song>.mp3` + `lyrics.txt` in a song folder.
2. Run the `song-analysis` pipeline: stems (htdemucs_ft) → pulse + key → **meter sweep
   (`detect_meter.py`; never assume 4/4)** → bass via pyin → chords via chroma+bass-root
   → Whisper on the vocals stem.
3. Open Ableton; verify the MCP connection (`health_check` — see `ableton-mcp`).
4. Build, e.g.: "At <BPM> in <key>, build a Session scene with these chords per bar
   <chord_proposal>, a drum pattern matching <kick/snare logic>, and leave the bass slot
   empty for me to play."

## Troubleshooting (route, don't debug here)

- Noisy bass MIDI → pyin, not basic-pitch or CREPE; bass bleed → `htdemucs_ft` + suppress
  pre-bass-entry bars; too few snares detected → `delta≈0.15`, un-normalized envelope
  (all in `song-analysis`).
- Can't connect / tools missing / device errors → `ableton-mcp`
  references/troubleshooting.md.

## Local environment (this machine)

- Analysis tooling + venvs: `~/dev/abletonAI/audio-analysis/`
  (`.venv-bp`, `.venv-demucs`); song folders live next to it in
  `~/dev/abletonAI/`.
- Ableton MCP configured via that project's `.mcp.json`.