git:20260925.2eb4071 to git:20260926.4fa1459

---

name: song-to-ableton

---

# 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.

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.