The A20: Musical Metaphors for Interface Design

We combine two concepts, the musical instrument as metaphor and technology probes, to explore how tangible interfaces can exploit the semantic richness of sound. Using participatory design methods from Human-Computer Interaction (HCI), we designed and tested the A20, a polyhedron-shaped, multichannel audio input/output device. The software maps sound around the edges and responds to the user’s gestural input, allowing both aural and haptic modes of interaction as well as direct manipulation of media content. The software is designed to be very flexible and can be adapted to a wide range of shapes. Our tests of the A20’s perceptual and interaction properties showed that users can successfully detect sound placement, movement and haptic effects on this device. Our participatory design workshops explored the possibilities of the A20 as a generative tool for the design of an extended, collaborative personal music player. The A20 helped users to enact scenarios of everyday mobile music player use and to generate new design ideas.