Button Accordion on iPad and iPhone

The treble side of a chromatic button accordion is an isomorphic keyboard: a scale or chord has the same fingering in every key. Musix Pro, an isomorphic MIDI keyboard for iPad and iPhone, includes the C-System, B-System and Bajan button layouts, so you can practise patterns, work out a tune or play an accordion sound when your instrument isn't with you.

Which layouts are included?

• C-System: the chromatic button accordion layout common in Western Europe.
• B-System: the mirror image of the C-System, common in Eastern Europe and Russia.
• Bajan: a B-System layout named after the Russian bayan.

On each, notes along a row rise by minor thirds, and moving across the rows moves by semitones. Musix Pro also has the Wicki-Hayden layout, used on concertinas, and other isomorphic layouts to compare. See all Musix Pro layouts.

What you can do with it

• Practise right-hand scale and chord shapes on a layout that matches your accordion.
• Play the built-in accordion sound, one of eight instruments synthesized in the app.
• Send MIDI (Bluetooth, network or virtual MIDI) to play accordion samples in another app or in your DAW.
• Label notes by name or solfège, and colour the notes of a key or scale.
• Resize the buttons to suit your fingers and screen.

What it doesn't do

Musix Pro is a touchscreen keyboard, not an accordion simulator. It has no bellows control and no Stradella bass (left-hand) side, and it doesn't record audio. To record, route it through Audiobus or send MIDI to a DAW or recording app.

Price and devices

Musix Pro runs on iPad and iPhone. It costs US$9.99 (prices vary by country) as a one-time purchase, with no subscription and no ads. The accordion layouts are included.