Optimized Spherical Sound Source for Room Reflection Analysis

Abstract:
Spherical loudspeaker arrays are commonly used for measurement tasks in room and building acoustics due to their omni-directional radiation. Using an individual excitation of their membranes allows to form a radiation with arbitrarily pronounced directivity patterns, with a maximal spatial resolution depending on the frequency and on the number of transducers used. In this contribution, an optimized spherical sound source is described which maximizes the spatial resolution by using a set of sequential measurements with different orientations of the source. A superposition approach allows to form various directivity patterns, which can be set to narrow beams in order to scan the room of interest with respect to the room reflections. The measured impulse responses can give insight into the parameters of the reflecting walls. Index Terms — Room acoustics, reflection detection, sound source, spherical harmonics