capfuse: Mashup & Remix Maker
Stem Splitter: Auto BPM & Key
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
The iOS mashup maker with AI stem separation built in. Every import splits into vocals, drums, bass and other, free. Vocal remover, acapella, auto key and BPM detection.
Make a mashup in 30 minutes — even if you have never DJed.
capfuse is a mashup and remix maker for iPhone and iPad. Import a track and it splits into vocals, drums, bass and other, detects the key and BPM, and shows you which songs in your library fit with it. You decide which phrase goes where — capfuse makes sure it lands on the beat.
WHAT YOU CAN DO
- Make a mashup of two songs on your iPhone
- Remove the vocal from a track and play the instrumental inside the app
- Play a song without its vocal, karaoke-style, inside the app
- Isolate a vocal — an acapella — and lift it onto a different song
- Find the key and BPM of any track in your library
- See which of your songs are harmonically compatible
- Build a remix out of records you already own
AI STEM SEPARATION, FREE AND AUTOMATIC
Every track you import is split into four stems — vocals, drums, bass and other — by an AI model 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, and play the result inside the app.
Guitars, piano and strings are grouped into "other". capfuse separates four parts, not every instrument.
AUTOMATIC KEY AND BPM DETECTION
Import from your music library or from Files. Every track is analyzed and tagged with its key and tempo. Video files such as mp4 work too — the audio is extracted automatically.
COMPATIBLE TRACK SUGGESTIONS
Pick a base track and capfuse lists the songs in your library that are harmonically compatible with it. 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.
IT IS NOT AN AUTO-MIXER
capfuse will not pick two songs and blend them on its own. Which phrase from which track goes where is your call — that is the part worth doing. What it takes away is the tedious part: tempo, alignment, key and BPM.
BUILT-IN LIBRARY
Finished mashups are mixed down and saved to your library. They play back like any music app, with background playback and lock screen controls.
FREE TO START
Import tracks, split stems, detect keys and build mashups for free. Premium removes the limits on how many source tracks you can register and how many mashups you can create.
GOOD TO KNOW
Separated stems and finished mashups play inside capfuse. There is no audio export, so they cannot be saved out as files.
Made for anyone who has ever heard two songs and thought "those would go together.
Ratings & Reviews
Added a feature to import demo projects.
The developer, Hiroaki Iwai, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Contact Info
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- User Content
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Hiroaki Iwai
- Size
- 18 MB
- Category
- Music
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- premium $1.99
- Copyright
- © Hiroaki Iwai