Stems & analysis
Pull a song apart into drums, bass, vocals — and let the app hear tempo and hits for you.
Every source you bring in can be listened to three ways: separated into stems, analyzed for tempo, and scanned for transients. All three run in the background and cache with the source — you ask once, the app remembers forever.
Stem separation
One click splits a source into drums, bass, vocals, and other (plus useful combinations like drums + vocals). On Apple Silicon this runs on the GPU; a full song takes about as long as a coffee refill.
What stems unlock:
- Chop the vocal without the band. Select the vocal stem and your pads play isolated voice.
- Mute the drums and be the drummer. Play the instrumental stem as a backing loop and cut your own hits over it.
- Swap a clip’s audio after the fact. A chopped clip can trade its audio for any stem of the same moment — the picture keeps playing, the sound changes clothes.
Guide stems while chopping
While chopping, the selected guide stem controls what you look at and listen to and what the Hits tool analyzes. It does not change the media stored in the new clips: chops remain backed by their original source.
Why you’d want that: vocals are legato — smeared onsets, few clean transients. Drums are a grid of them. So chop a vocal against the drums-and-vocals stem, where the transient detector has something to grab. After the cuts are created, swap the resulting clips to clean vocals (or any other available stem) with the Stems feature. This keeps chopping focused on boundaries and makes stem choice editable at any time.
Beat analysis
The app detects tempo, beats, bars, and key for any source. This feeds everything rhythmic: beat chopping, tempo sync, “adopt this BPM,” count-ins.
Detection is good but corrigible. When it hears double-time (184 for a 92 BPM song), press ½x. When the downbeat is off, put the playhead on the real one and press Set bar 1 here. Corrections persist — the app never re-argues with you about a source you’ve already settled.
Transient detection
Transients — the onsets the Hits chop tool uses — are detected per source and per stem, each onset carrying a strength. That’s why “give me the 16 best hits” is a meaningful request: they’re ranked, not just found, and each cut is refined down to the exact sample where the attack begins so your pads speak instantly.