capfuse: Mashup & Remix Maker

Make a mashup in 30 minutes — even if you have never DJed.

capfuse is a mashup and remix maker for iPhone and iPad. Pick one song for the beat and one for the vocal. capfuse splits both into stems, detects the key, BPM and phrases, and lays the vocal over the matching phrases of the beat — chorus on chorus, verse on verse. You start from a mashup that already plays, then make it yours.

WHAT YOU CAN DO
- Make a mashup of two songs on your iPhone
- Put the vocal of one song over the beat of another
- Remove the vocal from a track and keep the instrumental
- Isolate a vocal — an acapella — and lift it onto a different song
- Export your mashups as audio files
- Export stems, or a karaoke track and an acapella (Premium)
- Find the key, BPM and structure (verse, chorus, bridge) of any track
- See which of your songs are harmonically compatible
- Cut and insert phrases bar by bar
- Start right away with built-in demo songs

PICK A BEAT AND A VOCAL
Choose one track for the beat and one for the vocal. Each pick starts a preview from the chorus: the beat plays without its vocal, the vocal plays on its own, and once both are set you hear them together. Create the project and the vocal is placed onto the matching phrases of the beat. It is a starting point, not a finished mix — what happens next is up to you.

AI STEM SEPARATION, FREE AND AUTOMATIC
Every track you import is split into four stems — vocals, drums, bass and other — by AI models running on import. Nothing to switch on, and no paywall in front of it. It doubles as a vocal remover and a stem splitter: mute the vocal and keep the backing, or solo the vocal on its own.
Guitars, piano and strings are grouped into "other". capfuse separates four parts, not every instrument.

AUTOMATIC KEY, BPM AND PHRASE DETECTION
Import from your music library or from Files. Every track is analyzed for key and tempo, and divided into phrases: verse, pre-chorus, chorus, bridge and interlude. Video files such as mp4 work too — the audio is extracted automatically.

COMPATIBLE TRACK SUGGESTIONS
Once one side is chosen, capfuse lists the songs in your library that fit with it, most compatible first. No Camelot wheel, no music theory, no guesswork. Choose from what already works.

AUTOMATIC BEATMATCHING
Tempos are synced for you and phrases land on the downbeat. Blending two songs normally means matching keys by ear and nudging tempos until they lock. capfuse does that part.

EDIT ON THE BEAT
Select a beat, cut bars before or after it, and the rest closes up. Insert a phrase and it is fitted to the project's tempo — from the beat song you get the backing, from the vocal song just the vocal. Add more tracks and stack a third song on top.

WHAT CAPFUSE DOES, AND WHAT YOU DO
capfuse handles the tedious part: stems, key and BPM, phrases, tempo and alignment, and a first arrangement to start from. Which phrase to cut, what to bring in and where the mashup goes from there is your call. That is the part worth doing.

DEMO SONGS INCLUDED
The first launch walks you through a mashup made from demo songs, before you import anything. Demo songs and projects do not count toward the free limits.

LIBRARY AND EXPORT
Finished mashups are saved to your library, with background playback and lock screen controls. Export one as an m4a file to Files, AirDrop or another music app.

STEM EXPORT (PREMIUM)
Export the stems of your own tracks: four files (vocals, drums, bass, other), or two (vocals and instrumental) for a karaoke track or an acapella. Turn on "Split by phrase" to get one numbered, labeled file per phrase, ready for your DAW.
Use only audio you own or have permission to use.

FREE TO START
Import, split stems, build mashups and export 3 of them for free. Premium removes the limits on source tracks and mashups, makes exports unlimited and adds stem export.

Made for anyone who has ever heard two songs and thought "those would go together.