HexaChrom – A Hexagonal MIDI Controller For The iPad

HexaChrom iPad MIDI controller

HexaChrom (App Store link) is a $3.99 app that turns your iPad into a hexagonal performance controller, enabling you to wirelessly play OSC or MIDI musical instruments — virtual instruments running on a laptop/desktop computer, or any hardware instruments attached to your laptop/desktop computer.

HexaChrom uses an isometric note layout, where the notes are presented as a hexagonal matrix of keys.

There are many such isometric layouts, though HexaChrom uses the Harmonic Table layout, which is a modern variation of the Tonnetz (tone network), devised by the mathematician Euler.

This note layout has particularly useful musical intervals between adjacent keys, ie along the 3 major axes : minor thirds, major thirds and perfect fifths.

This layout offers a number of advantages over the more conventional clavier-style keyboards:

  • consistent chord shapes irrespective of key;
  • span several octaves with one hand;
  • play basic major or minor triads with a single finger;
  • easier learning curve; and
  • encourages the user to approach music differently, just as the different note layouts of pianos and guitars engender different playing styles.

HexaChrom sends MIDI data via the OSC protocol, using OSC’s “M” data type. To control MIDI devices (hardware or software) you will need to run an application on a laptop/desktop computer to translate the OSC messages into MIDI messages. For Mac users, OSCulator is the preferred solution.

HexaChrom looks very interesting – but we’d like to see it support hardware MIDI, via USB devices and the Line 6 MIDI Mobilizer.

If you’ve used HexaChrom, leave a comment – we’d be interested in your thoughts on it!


  • Isometric ‘harmonic table’ note layout keyboard, based on a 52-note matrix (just over 4 octaves).
  • Play simple chords with a single finger.
  • Consistent chord shapes irrespective of root key.
  • Octave transposition provides a total span of just over 7 octaves.
  • Dual view : Portrait mode offers a single 52-note matrix (easy play); Landscape mode has a 104-note dual matrix, with optional split channel operation.
  • Assignable controllers (sliders and buttons).
  • Connects wirelessly using the OSC protocol.
  • Automatic connection using bonjour, or manual connection when bonjour is not an option.
  • Using OSCulator (on a Mac) control any software or hardware MIDI synthesizer, sampler, drum machine, etc.
  • Multitouch interface.


  • iPad running iOS 3.2, or later.
  • A local wireless network (setting up a temporary ad-hoc network is recommended).
  • A Mac running OS X 10.4, or later.


  • HexaChrom is a controller. It does not of itself produce any sound.
  • To control MIDI devices, additional software (eg OSCulator, on a Mac) is required

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