Strung Along: A violin-based interactive music system for real-time chordal accompaniment and timbral control

This thesis proposes Strung Along, a novel violin-based interactive music system which provides real-time chordal accompaniment to a monophonic melody played by a violinist, with momentary control of timbre and chord voicing afforded through modulation of tracked bowing parameters. Two sub-systems are implemented and evaluated separately, before being integrated and evaluated as a combined system; firstly, the chord generation sub-system implements a novel approach for chord generation using chroma histogram representations as training data for a machine learning model, and implements this model in a real-time system which generates one chord per melody note. This is shown to be effective for generating chords using regression techniques, although performance in modelling chord order is limited. Secondly, the bow tracking sub-system adapts an existing approach for tracking bow position and bow force as part of an interactive system for the first time, while implementing changes aimed at simplifying and lowering the cost of the approach. These changes are shown to negatively impact the accuracy and precision of the measured parameters, but the approach nonetheless remains viable as a low-cost method for tracking bow force as a mapping parameter. The combined system offers just one approach to combining the two sub-systems, in which a chord is generated in real time for each melody pitch played by the violinist. An autoethnographic evaluation finds it to be an engaging partner for musical co-creation between a human performer and a digital system. Complexifying the relationship between melody input and chord output, and improving the algorithm used to voice the chords, are presented as areas for future work.