This paper is a reflection on our experience of design of an interactive instrument and its evaluation and redesign using a collaborative creativity process. This paper examines the interface from three different perspectives; designer, performer, and expert audience. The designer describes and evaluates the chain of decisions taken to release an experimental tangible interface for professional use by a duo of electronic musicians. The performers examine the usability aspects, and a group of composers participate in a creative workshop to explore different aspects of the interface in a collaborative creativity process.