PREPRO — Vocal Demos

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  Screenshot: COMP screen, no device frame (1179 x 2556)

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  App icon (1024 x 1024)

Inspiration

Rappers and singers get ideas anywhere, but turning an idea into a demo usually means a laptop, a DAW and a lot of setup. We wanted the whole loop — beat, lyrics, takes, best take, playback — to fit on one iPhone screen, so you can go from "I've got a verse" to "listen to this" in minutes.

What it does

• Drop in a beat: start with a free built-in beat (or import your own with VIP). PREPRO detects the BPM and key.
• RANGE: pick the bars you want to record from a grid of bar blocks.
• LYRICS: write lyrics that stay on screen while you record.
• REC: count-in, sing, save. Record as many takes as you need.
• Pitch correction: set it to HARD and your vocal is tuned to the song's key.
• COMP: every take gets its own color. Drag the IN/OUT handles to choose which part of each take ends up in the demo.
• Layers: record on MAIN, LAYER and ADLIB to build out the vocal.
• Playback: hear the finished demo with beat, vocals and lyrics together.
• Themes: 8 genre themes, from TRAP NOIR to NEON TOKYO, restyle the whole app.

How we built it

PREPRO is a native iOS app. Subscriptions (the VIP pass, monthly and annual) run on RevenueCat, which handles purchases, restores and entitlement checks. The free tier lets anyone create, write, record and use pitch correction with built-in beats; VIP adds importing your own audio and MP3 / WAV stem export.

Challenges we ran into

Recording on a phone means timing matters: the vocal has to land on the beat after count-in, and comping only works if every take lines up. We also had to fit a multitrack workflow (takes, layers, ranges) into a single phone screen without it feeling like a desktop DAW.

Accomplishments that we're proud of

The demo video itself: the verse at the start and end was written and recorded in PREPRO on an iPhone.

What we learned

People don't want more knobs — they want to get the take down while the idea is fresh. Every screen in PREPRO is built around one next action.

What's next

More built-in beats, and more ways to share a finished demo.

Built With

• ios
• revenuecat
• swift