In Theory - Interval Keyboard 2.2

In Theory presents itself as a sophisticated interval-based MIDI keyboard application, boasting an impressive library of over 110 scales. The interface features a keypad positioned at the bottom, equipped with interval buttons labeled +2, +1, 0, -1, and -2, each serving to adjust the current note within the selected scale. Here, '0' corresponds to the current note, '+1' denotes the immediate subsequent note, '+2' advances two notes forward, while '-2' retracts two notes back.

Above the keypad lies functionality for toggling additional intervals within the scale, enabling users to construct various chord voicings. The application also allows for selection of notes from an octave above and below, promoting the creation of rich and extended chords.

For those utilizing external MIDI hardware, In Theory seamlessly integrates with your MIDI keyboard. Specifically, pressing the middle C4 key will activate the '0' button on the app's keypad. Subsequent white keys beyond C4 correspond to positive interval buttons, whereas those preceding C4 trigger negative intervals.

The app further supports MIDI CC message toggling for chord intervals. Users can assign a specific MIDI CC number and channel through the settings menu; sending a MIDI CC value between 0 and 62 allows for respective toggling of chord intervals.

Additionally, In Theory's MIDI capabilities extend to integration with sequencer applications such as PolyBud, ShiftBud, and MelodyBud. This enhances creative opportunities for sequencing compositions directly within those platforms.

The application’s extensive scale library is complemented by support for custom scales designed in ScaleBud 2. Moreover, users can externally modify key and scale via a MIDI controller when utilizing the app as an AUv3 plugin with AU parameters.

The user interface features a circular display that visually represents one’s position within the scale. Engaging a note generates real-time visual feedback of each note played on-screen along with its root note and corresponding chord intervals.

It is essential to note that In Theory functions exclusively as a MIDI application; it does not generate sound independently. Users are required to connect its MIDI output to the MIDI input of an audio application. For AUv3 plugin usage, an AUv3 host application such as AUM, Cubase, Nanostudio, or apeMatrix is necessary.