State-space simulation of sound source directivity for interactive geometric acoustics

A method is proposed for simulating the frequency-dependent directivity of sound sources for use in interactive geometric acoustic rendering applications. The method is based on using measurements to design a state-space filter allowing the interactive simulation of a time-varying number of radiated sound wavefronts, each towards a time-varying direction. With applicability in sound synthesis or auralization within virtual environments where sound sources dynamically change position and orientation, techniques are proposed for modeling and simulating directivity profiles on perceptually motivated warped frequency axes, along with alternatives for representing directivity on a per-vibration-mode basis or by reduced-order efficient representations. We demonstrate the method by using experimental acoustic data to simulate the directivity of a violin body and a clarinet air column.