Hohner MIDI Piano Accordion 2.4

The Hohner MIDI Piano Accordion functions as a MIDI control surface styled after a traditional piano accordion, designed specifically for the iPad platform. It does not generate sound independently, but rather interfaces with hardware or software synthesizers through CoreMIDI compatibility. This allows users to control external MIDI hardware or virtual instruments like Roland Sound Canvas, IK Multimedia SampleTank®, or Sonosaurus ThumbJam installed on the device.

The interface features a two-octave, 24-key treble keyboard coupled with 36 bass and chord buttons. Users can select from various configurations on the left side, including Bass, Major, Minor, 7th chords, or combined Counter Bass/Major/Minor setups. The bass and chord section can be transposed within a two-semitone range via a control located at the bottom left of the screen; however, note labels do not update to reflect this transposition, which may be improved in future software updates. The transposing feature effectively shifts the entire bass range up or down by two rows.

Multiple button presses are supported simultaneously, and sliding fingers between buttons allows for fluid playing. A dedicated MIDI connector button reveals parameter controls enabling precise customization of MIDI channel, velocity, and volume for the treble, bass, and chords separately. Additionally, global transpose settings accommodate changes up to twelve semitones in either direction.

The app allows for four user-defined MIDI presets that can be accessed directly from the main interface for quick switching during performance. These presets are saved automatically upon app closure. The "Transmit MIDI Port" switch toggles between "Omni," which broadcasts MIDI data to all CoreMIDI-compatible apps, and "Virtual Port," directing output to a named virtual port recognized by compatible software like ThumbJam or MidiBridge. "Omni" mode is the default setting.

All MIDI configurations are preserved across sessions. The octave shift function at the bottom of the display permits shifting the treble side up or down by one octave relative to current transposition settings; this adjustment is saved within each preset. Touching the '?' icon displays note labels for each button without transposition applied, aiding in navigation. The '!' button sends an "All Notes Off" message proactively to prevent stuck notes.

Additional controls include pressing the Hohner logo to access a help screen with links to the Hohner accordion website and online lesson resources via Accordion Life.

The app's programming accurately reflects realistic chord inversions based on traditional piano accordions through precise MIDI note mapping. User preferences are saved automatically when exiting.

For optimal functioning with popular synth apps like IK Multimedia SampleTank® and Sonosaurus ThumbJam, specific settings adjustments are recommended: enabling "Background Audio" in SampleTank® settings and activating "Use CoreMIDI" along with "Active in Background" within ThumbJam preferences. Users should consult the support site for demonstrations and detailed configuration guidance tailored to their specific software environment.

Disabling "Multitasking Gestures" in iPad Settings is essential for full multi-finger performance capabilities beyond three fingers at once.