DuoBox: Fold Accordion

An accordion for iPhone Duo. Hold the open phone like a book: bass buttons under your left thumb, treble keys under your right. Folding the phone works the bellows. Opening is pull, closing is push, and the faster you fold, the louder it plays. Every sound is synthesized on the phone. No samples, no accounts, no subscription.

Free to play, with a one-time $4.99 unlock for every register, effect and song, WAV stems and MIDI out. The unlock works with Family Sharing.

Support

No sound?

The reeds only speak while the bellows move. Hold a key, then open or close the phone. On an iPhone without a hinge, hold a key and drag the pleats in the middle up and down. Holding the AIR button moves the bellows silently, so let go of it to play.

Restoring the unlock

The unlock comes back on its own on the same Apple Account. If it doesn't, open any locked register and tap Restore Purchase.

Recording into Logic Pro or another DAW

Tap the red dot to record. In the Studio sheet, WAV exports two 48 kHz, 24-bit stems: the full sound and a dry stem without effects, lined up to the sample. Turn on the metronome or count-in and each take starts on the downbeat, with the tempo in its file name, so it lands on bar 1 of a project at the same tempo.

MIDI out

Treble plays on channel 1 and bass on channel 2. The bellows can send Expression (CC 11), Mod Wheel (CC 1) or Breath (CC 2); Logic's Studio Strings and Studio Horns follow the mod wheel. Connect over Bluetooth MIDI, or turn on Wi-Fi MIDI and, on a Mac, open Audio MIDI Setup, choose Window › Show MIDI Studio, double-click Network and connect to your iPhone. Wi-Fi MIDI lets any computer on the network connect while it's on, so use it on networks you trust. It turns off when you quit DuoBox.

Something else

Email aaron@aaronpeabody.dev. I read everything.