Mix Directive Part Writers (bass and keys, v1)
The models behind Suggest Part ▸ Bass and Suggest Part ▸ Keys in the Mix Directive desktop app. Given a song's chords, key, drums and lead vocal (read from its MIDI), they write a bass line or a keyboard part as MIDI notes.
These models are proprietary. They are published here only so the Mix Directive app can download them on demand. Using them outside the app, redistributing them, or building on them is not permitted: see LICENSE.md.
Files
| File | What it is | SHA-256 |
|---|---|---|
bass.onnx |
the bass writer (ONNX, 26 MB) | d324e565be48be7f5f9623b8895469bafe3685f1231e70e9a561f2923b945cee |
keys.onnx |
the keys writer (ONNX, 26 MB) | 464f0b738dfd2b23bb645762917116a93d868fcff0bcc8ea4803adedf1bbfe6b |
The app pins a specific commit of this repository and checks each file's SHA-256 before using it.
Model
- Architecture: a small transformer (6.4M parameters) over eight 4/4 bars, one step per 16th note. Both files are the same network with different weights.
- The bass writer writes one note at a time. The keys writer writes when a chord is struck, how long it is held and its shape (how many notes, which chord tone is on top, which octave); the notes themselves come from the song's chords.
- Weights: trained from random initialisation by Mix Directive. No pretrained third-party weights were used.
- Training data: MIDI of music owned by the Mix Directive author, used with full rights. The models do not contain or reproduce that music.
Intended use
Writing a starting part for a song the user has the right to work on, inside the Mix Directive app. A written part is a suggestion to edit: it follows the song's chords, but its rhythm matches what a player would do no better than the app's rule-based parts.
License
Mix Directive Part Writers Model License v1.0 — see LICENSE.md. All rights reserved.