How to get better separation
The separation quality depends mostly on the song itself, but the file you start from and the device you use make a difference too. Here is what helps.
Start from the best file you have
- Lossless is best – WAV and FLAC keep every detail. A recording straight from your band's mixing session (the stereo mix) is ideal.
- MP3 and AAC are fine at a good bitrate – 256–320 kbps MP3 or 256 kbps AAC (M4A) separates nearly as well. Low-bitrate files (128 kbps or less) have lost high-frequency detail, which shows up as a swishy sound in the separated parts.
- Do not convert a lossy file to WAV to “improve” it – what was lost is not restored.
- Stereo is better than mono – the difference between the left and right channels is one of the clues the model uses. Mono files work, but separate less cleanly.
- Recordings from a phone in the rehearsal room work for practice, but room echo and distortion make the parts blur into each other.
Music from streaming services (Apple Music, Spotify, YouTube) cannot be opened: use files you have.
Songs that separate well, and songs that do not
| Separates well | Harder |
|---|---|
| A typical band: vocals, guitar or keys, bass, drums | Instruments the model rarely heard: synth bass, orchestral music, unusual percussion |
| A clear, dry mix with space between instruments | Lots of reverb, heavy distortion, very loud (heavily compressed) masters |
| One lead singer | A choir or many layered voices; spoken word over music |
| Studio recordings | Live recordings with crowd noise; old recordings with hiss |
Why these are harder is explained in how AI separation works.
Use a computer for long songs
- A computer is much faster than a phone, especially with a recent graphics chip and a browser that supports WebGPU (recent Chrome and Edge, for example).
- Songs up to 12 minutes can be separated on a computer, and up to 8 minutes on phones and tablets. For a longer recording, such as a whole rehearsal, cut out the song you need first.
- Separate on a computer, practice anywhere: save the parts or your mix as MP3 files (about 5.8 MB for a 4-minute song at 192 kbps) and play them on your phone.
If it stops partway
Separation needs about 1 GB of memory while it runs. If the device runs short:
- Close other tabs and apps before you separate, and keep the screen on.
- If an error appears, the app tries again automatically with settings that use less memory.
- If the page reloads by itself, the browser closed it for lack of memory. The app remembers the setting that stopped and uses a lighter one next time: choose the song again and press “Separate into 4 parts”.
- If it still stops — which can happen on iPhone and iPad — separate on a computer and use the saved MP3 files on that device.
After separating
- If a muted part can still be heard faintly, turn the other parts up a little rather than the volume down: the trace is quieter than the parts around it.
- If a part sounds thin or swishy on its own, listen to it together with one other part (solo two parts): the artifacts are much less noticeable.
- Save the parts you want to keep. They are not kept in the app, and separating again takes the same time.