DAFx-2011 - Paris

Interactive navigation within geometric, feature-based database representations allows expressive musical performances and installations. Once mapped to the feature space, the user’s position in a physical interaction setup (e.g. a multitouch tablet) can be used to select elements or trigger audio events. Hence physical displacements are directly connected to the evolution of sonic characteristics — a property we call analytic sound–control correspondence. However, automatically computed representations have a complex geometry which is unlikely to fit the interaction setup optimally. After a review of related work, we present a physical model-based algorithm that redistributes the representation within a user-defined region according to a user-defined density. The algorithm is designed to preserve the analytic sound-control correspondence property as much as possible, and uses a physical analogy between the triangulated database representation and a truss structure. After preliminary pre-uniformisation steps, internal repulsive forces help to spread points across the whole region until a target density is reached. We measure the algorithm performance relative to its ability to produce representations corresponding to user-specified features and to preserve analytic sound–control correspondence during a standard density-uniformisation task. Quantitative measures and visual evaluation outline the excellent performances of the algorithm, as well as the interest of the pre-uniformisation steps.

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