Support & FAQ

A "stem" is one of the individual instrument tracks that make up a song. MonoBand uses an on-device AI model (HT-Demucs) to listen to a mixed recording — for example, an MP3 of your favourite song — and reconstruct 6 separate tracks: vocals, drums, bass, guitar, piano, and "other" (synths, strings, brass, anything that doesn't fit the first five). You can then play any combination of those stems together at any volume, so you can practice the bass line alone, drop the vocals to sing along, or remix the song from scratch.

No. Every audio operation — stem separation, BPM detection, key detection, transpose, time stretch, mixdown — runs locally on your device using Apple's Neural Engine. You can use MonoBand on a flight, in the studio, on a train with no signal, anywhere.

Roughly real-time on a modern iPhone (an A17 or M-series chip) — meaning a 3-minute song takes 2–3 minutes to separate. Older devices and Macs without Neural Engine acceleration may take longer. Once a song is split, the stems are cached on your device, so you only pay the cost once.

Any audio file you can read on your device — WAV, MP3, M4A, AAC, FLAC, ALAC, and the audio track of MP4/MOV videos. Bring them in from the Files app, the Photos app, your Music library, or record fresh audio with the built-in recorder.

Note: DRM-protected files (such as tracks streamed from Apple Music or Spotify) cannot be imported — iOS restricts apps from reading their decrypted audio. Use songs you own outright.

Transpose shifts the song up or down in musical pitch (in semitones) without changing how fast it plays. Useful for moving a song into your singing range or a guitar-friendly key.

Speed change changes how fast the song plays without changing its pitch — handy for slowing down a difficult solo to learn it note-for-note, or speeding the song up to test your timing.

Both controls live side-by-side just above the transport bar, and they stack — you can transpose AND change speed at the same time.

While playback is running, tap Set A at the start of the section you want to loop, then tap Set B at the end. Playback now bounces between those two markers indefinitely. Tap the × button to clear the loop and resume normal playback.

Section markers are bookmarks you can drop anywhere in a song — at the start of the verse, chorus, bridge, solo, etc. Tap the + button on the Sections bar to add a marker at the playhead. Tap any marker chip to jump straight there. Long-press a marker to rename or delete it.

Yes. Each project has up to 4 user-recording slots. Tap a slot to start recording — the song plays back while you record, so you can sing or play in time. Each take gets its own volume, solo, and mute controls, just like the AI stems.

Yes. MonoBand uses the standard iOS audio session, so playback routes automatically to whatever is connected — AirPods, Bluetooth headphones, an AirPlay 2 speaker, an Apple TV, or your car. Play, pause, and skip controls work from the Lock Screen, Control Center, and AirPods squeeze gestures.

Inside MonoBand's app sandbox on your device. If you delete the app, iOS deletes all your projects and stems with it — there is no cloud backup of MonoBand-specific data. To preserve your work, use the Export Library button in Settings to save a ZIP of every project's audio and metadata.

Inside a project, tap the Export All menu next to the stems list. Choose either "All as WAV" (lossless, full quality) or "All as MP3" (compressed). iOS opens the share sheet so you can send the stems to your DAW via AirDrop, Files, iCloud, Dropbox, or anywhere else.

We don't have plans to add either. The on-device, no-server design is a core part of what MonoBand is. If iCloud Drive or CloudKit support becomes the right tool for syncing your own projects between your own devices, we'll consider it — but always with end-to-end encryption and with no MonoBand account involved.