A Concentric Compact Spherical Microphone and Loudspeaker Array for Acoustical Measurements

Several commonly used descriptors of acoustical conditions in auditoria (ISO 3382-1) utilise omnidirectional transducers for their measurements, disregarding the directional properties of the source and the direction of arrival of reflections. This situation is further complicated when the source and the receiver are collocated as would be the case for the acoustical characterisation of stages as experienced by musicians. A potential solution to this problem could be a concentric compact microphone and loudspeaker array, capable of synthesizing source and receiver spatial patterns. The construction of a concentric microphone and loudspeaker spherical array is presented in this paper. Such a transducer could be used to analyse the acoustic characteristics of stages for singers, while preserving the directional characteristics of the source, acquiring spatial information of reflections and preserving the spatial relationship between source and receiver. Finally, its theoretical response and optimal frequency range are explored.