2.5 dimensional sound field reproduction based on mode matching and equivalent sources considering primary reflections

Abstract

Many sound field reproduction methods using many loudspeakers (secondary sources) have been studied to reproduce a physically-accurate sound field. In our previous research, we proposed a pressure matching method using the modeled transfer functions of the secondary sources based on the sparse equivalent source method (ESM). By modeling the sound field emitted from the loudspeaker, the number of measurement points required for pressure matching can be significantly reduced. Moreover, another well-known method of sound field reproduction is Mode Matching (MM). In the MM method, the driving functions are derived such that the weight coefficients of the spherical harmonics are matched between the desired and reproduced sound fields. In this study, we proposed an implementation of the MM method based on the ESM considering the sound reflections and loudspeakers' directivity. We estimate the spherical harmonic coefficients of the loudspeakers and sound reflections based on the superposition of equivalent sources. In the simulation experiments, we evaluate the reproduction accuracy achieved with the first-order sound reflections.