The difficulties of evaluating DMIs (digital musical instruments), particularly those used by ensembles of musicians, are well-documented. These devices are designed to support creative expressions that are often improvised and unexpected from the designer’s point of view. In collaborative music-making settings, interactions between performers are highly complex and can be almost impossible to directly examine the impact of a new interface. In such situations, traditional human-computer interaction (HCI) metrics such as time-to-completion may be inappropriate given that longer improvisations can be seen as more desirable.

To address some of these issues, we propose a methodology of rehearsal-as-research to study free-improvisation by ensembles of DMI performers. Sessions are structured to mirror established practices for training in free-improvisation. These sessions also allow controlled, order-balanced studies with extensive data collection in the style of factorial HCI experiments. Experiment structures, designs for questionnaires, and objective measures such as session duration will be discussed. We ask whether improvised rehearsal processes from music could apply more broadly to studying collaborative interaction.

Keywords: New Interfaces for Musical Expression (NIME); Evaluation; Methodology; Rehearsal; Improvisation; Collaboration.