A study is presented examining the participatory design of digital musical interactions. The study takes into consideration the entire ecology of digital musical interactions including the designer, performer and spectator. A new instrument is developed through iterative participatory design involving a group of performers. Across the study the evolution of creative practice and skill development in an emerging community of practice is examined and a spectator study addresses the cognition of performance and the perception of skill with the instrument. Observations are presented regarding the cognition of a novel interaction and evolving notions of skill. The design process of digital musical interactions is reflected on focusing on involvement of the spectator in design contexts.