What are stems?
A finished song is normally one stereo file. A stem is a separate, synchronized audio file containing a grouped part of that song, such as drums, bass, vocals or keys.
A stem is not necessarily one instrument. A drums stem can contain kick, snare, hats, toms, cymbals and percussion. A keys stem can combine piano, organ, pads and synthesizers.
Bring separate audio parts. Prepare supported formats locally.
The complete MIDI, listening-WAV, Simple and Studio workflows still accept synchronised, top-level WAV stems. The local folder importer can prepare 2–64 already-separated, synchronized top-level audio parts as one project containing immutable originals, canonical top-level PCM24 WAV stems, per-source and aggregate receipts, and one source-project manifest.
Sunofriend does not yet separate one finished song into stems, and the public website does not receive audio. Folder preparation does not shift, pad, stretch, normalize or align parts, and it does not prove the musical downbeat.
Remove --plan only after checking the read-only plan. Execution replans the current files rather than replaying a stored plan, so plan again after any input, role-map or option change. Missing recorded-origin evidence requires the explicit --accept-unconfirmed-origin acknowledgement; that is not proof that the parts are aligned.
For one standalone asset, sunofriend source-import SOURCE --out-dir FRESH --plan remains available. It does not make a complete song project.
Why the distinction matters
Made in the music project
If you made the song in a DAW, synchronized track or stem exports are normally the cleanest input. Export every part from the same start point to the same ending.
Separated from a finished mix
An AI separator estimates overlapping parts. It cannot recreate lost studio tracks exactly, so bleed, muffling and watery artefacts are normal and can become false MIDI notes.
A broad stem may later be refined, such as drums into kick, snare, hats, toms, cymbals and other percussion. That refinement is another estimate. Do not include both a parent drum stem and all of its child stems in one arrangement, or parts will be duplicated.
Three practical routes
Export from your DAW
Export synchronized parts from GarageBand or another DAW. Keep the same start, end, sample rate and song timing.
Usually the cleanest route when you made the music.Use supplied stems
An artist, collaborator, generator project or education library may provide stems or multitracks. Check the licence for that exact project and intended use.
Permission to practise is not permission to republish.Use an independent tool
A local application or cloud service can estimate stems from a finished song you are authorised to process. Listen to every result before asking Sunofriend to transcribe it.
Prefer lossless audio when it is available.Neutral provider starting points
Features, prices, export formats and terms change. These are ordinary official links, not a quality ranking. No provider has yet passed Sunofriend's downstream MIDI bake-off.
Moises
Detailed separation, including narrower drum parts on eligible plans.
Your audio is uploaded. Check the current plan, export format, retention and privacy terms before using private music.BandLab Splitter
A low-friction first experiment with separated parts and MIDI export.
Processing is online and some categories require membership. Check the current terms before uploading.Fadr
Stems alongside MIDI, chords, key and tempo, with paid refinements.
Review the current privacy and rights terms, especially for unreleased or confidential audio.Suno stem separation
Exporting parts from material already created in, or legitimately uploaded to, a Suno workflow.
A paid cloud feature. Confirm upload rights; category labels and requested splits are estimates.LALAL.AI
Target-plus-complement separation and a range of instrument categories.
The desktop app uses cloud processing by default. Check whether your plan and chosen model actually process on-device.Logic Pro Stem Splitter
On-device broad separation on supported Apple-silicon Macs.
Requires Logic Pro and supported Apple hardware. It is not available inside GarageBand.RipX DAW
Desktop separation, note-level inspection and MIDI export.
Commercial software. Check current macOS support and process only audio you are authorised to use.Check before you process
- Rights: Do you own the recording, have permission, hold a suitable licence or have another lawful basis?
- Privacy: Is the song unreleased, confidential or commercially sensitive?
- Location: Does the chosen tool process on your Mac or upload the audio?
- Provider terms: How long are uploads and derived files retained, and may they be used to improve a service?
- Outputs: May you publish the MIDI, remix, sample-based instrument or separated audio?
Owning a stream, download or subscription does not automatically grant permission to upload, adapt or redistribute the recording. This is practical product guidance, not legal advice.
What to bring back
A folder of synchronized separated parts
- one song per folder;
- 2–64 top-level files intended to share a recorded start;
- WAV, AIFF, FLAC, M4A, MP3 or Ogg;
- clear names such as bass.flac and kick.wav;
- the song key and BPM if you know them.
Use source-import-folder --plan, review its roles and origin evidence, then explicitly execute into a fresh project. It preserves a broad drums part for later composite handling.
Do not map an observed part to pads: production currently synthesizes pads from keys. A genuinely string-like sustained part may be strings; otherwise leave it unresolved instead of mislabelling it.
Try the safe demo instead
The built-in demo creates synthetic source stems and runs the normal automatic MIDI, listening-WAV and ZIP path.