Hohner Chromatic MIDI 2.2

The Hohner Chromatic Button Accordion MIDI Controller serves as a CoreMIDI control surface designed specifically for the iPad, mimicking the functionality of a chromatic button accordion (CBA). While the application itself does not generate sound, it facilitates interaction with both hardware and software MIDI synthesizers through a CoreMIDI-compatible interface, whether connected via the dock connector or used with virtual MIDI instruments like Roland Sound Canvas for iOS, IK Multimedia SampleTank®, or Sonosaurus ThumbJam.

The button layout accommodates both B (Bayan) and C-systems, complemented by a built-in note guide that aids users in familiarizing themselves with the button arrangement. The left side of the instrument allows users to toggle between Bass/Major/Minor/7 or Counter Bass/Major/Minor configurations.

A noteworthy feature includes the ability to transpose the bass/chord side up or down by two semitones using a control on the bottom left of the screen. It is important to note that while the pitch transposition occurs, the accompanying note labels remain static; this potential enhancement may be addressed in future updates. This transposition feature effectively broadens the bass range by shifting it up or down two rows.

The app is designed to replicate the button spacing of a traditional accordion, enabling simultaneous button presses and allowing users to slide fingers between buttons for fluid playability. The MIDI connector button provides access to parameter controls where users can configure MIDI channels (1-16), velocity, and volume settings independently for treble, bass, and chord sections. Global MIDI transposition settings for all sections can also be adjusted within a range of +/- 12 semitones, with additional independent octave transposition capabilities for bass buttons.

On the MIDI control screen, users can select from eight banks, each containing four presets. The presets (A, B, C, or D) for a currently selected bank can be quickly accessed while performing on the main screen, eliminating the need to navigate away from play mode to switch sounds.

The application retains all preset configurations upon closure, ensuring continuity in user experience. The "Transmit MIDI Port" feature allows for selection between "Omni" mode—sending MIDI data to all CoreMIDI applications—and "Virtual Port," which directs output to a designated CoreMIDI virtual port. The latter enables compatibility with other applications supporting virtual ports, such as Sonosaurus ThumbJam and MidiBridge; "Omni" mode is set as default.

All MIDI adjustments are preserved when exiting the app, restoring settings upon relaunch. The option to shift octaves for the treble side—after any transpose adjustments—can be accessed via the octave shift select at the bottom of the play screen, with changes saved alongside current presets.

For added convenience, touching the '?' icon reveals the base layout note names associated with each button without accounting for transposition. Simultaneously, using the '!' button sends an "All Notes Off" message to silence any potentially stuck notes. Accessing help through the Hohner logo leads to resources about Hohner's accordion offerings and aligns users with online accordion lessons offered by Accordion Life.

This application accurately maps chord inversions from a real Chromatic Button Accordion to their corresponding MIDI note numbers. Users may need to make additional configurations within synthesizer applications for optimal functionality. For instance:

• IK Multimedia SampleTank: Enable "Background Audio" in Settings.
• Sonosaurus ThumbJam: Activate "Use CoreMIDI" and "Active in Background" under "MIDI Control" in "Prefs."

Similar settings are likely required in other CoreMIDI compatible synth applications. For further support, including live demonstration videos and specific settings suggestions for synthesizer compatibility, users are encouraged to visit the app's support website.

Please be advised that to fully utilize this app's capabilities—particularly if attempting multi-finger actions beyond three—it is recommended to disable "Multitasking Gestures" in your iPad's General Settings.