Many mobile music applications are typically quite limiting to musicians, as in attempting to virtualize a traditional interface they lose the playability afforded by the physical components. Another class of mobile applications, most notably loop machines, bypasses the touchscreen's lack of haptic feedback by delegating the majority of the audio mappings (binary, basic parametric, and expressive) to the computer, and user interaction is typically limited to pattern selection or pattern manipulation, in a manner unlike traditional instrumentation. Pitch Canvas was designed as an alternative to both types of mobile music applications, with the goal of offering real-time control of all audio in a non-skeuomorphic interface built around the touchscreen. Users interact with the interface through gestures, which are translated into pitches based on the touch location. The interface consists of hexagonally-structured circles representing the notes in a given major key and offers pitch bends for slides and slurs in the areas between the circles. Vertically adjacent notes are spaced in intervals of major or minor thirds allowing easy chord construction, and horizontally adjacent notes are separated by a tone or semi-tone, facilitating scales, trills, and arpeggios. An iPad case has been developed which offers haptic feedback, offering the user a means of feeling the borders between the notes to allow synchronization of events such as chord transition. Several improvements for the interface are in development, including the use of two tablets to control a single interface, addition of further degrees of freedom, and visual interaction.
This instrument formed the basis of an improvisation by the Laptop Orchestra of Louisiana. The research was also presented as a poster at LSU's Summer Undergraduate Research Forum.