Rich gesture, reduced control: the influence of constrained mappings on performance technique.

This paper presents an observational study of the interaction of professional percussionists with a simplified hand percussion instrument. We reflect on how the sound-producing gestural language of the percussionists developed over the course of an hour session, focusing on the elements of their gestural vocabulary that remained in place at the end of the session, and on those that ceased to be used. From these observations we propose a model of movement-based digital musical instruments as a projection downwards from a multidimensional body language to a reduced set of sonic features or behaviours. Many factors of an instrument's design, above and beyond the mapping of sensor degrees of freedom to dimensions of control, condition the way this projection downwards happens. We argue that there exists a world of richness of gesture beyond that which the sensors capture, but which can be implicitly captured by the design of the instrument through its physicality, constituent materials and form. We provide a case study of this model in action.