Acoustics Laboratory

Spherical microphone arrays are used for capturing three-dimensional sound fields, from which binaural signals can be obtained. Plane-wave decomposition of the sound field is typically employed in the first stage of the processing. However, with practical arrays the upper operating frequency is limited by spatial aliasing. In this paper, a measure of plane-wave decomposition error is formulated to highlight the problem of spatial aliasing. A novel method for plane-wave decomposition at frequencies that are typically considered above the maximal operating frequency is then presented, based on the minimization of aliasing error. The mathematical analysis is complemented by a simulation study and by a preliminary listening experiment. Results show a clear perceptual improvement when aliasing-cancellation is applied to aliased binaural signals, indicating that the proposed method can be used to extend the bandwidth of binaural signals rendered from microphone array recordings.