Broadband Multizone Sound Rendering by Jointly Optimizing the Sound Pressure and Particle Velocity

TL;DR

This paper analyzes and improves a multizone sound field synthesis method called JPVM, demonstrating that removing the tangential particle velocity component enhances performance and reduces complexity, with validation through simulations and noise impact assessment.

Contribution

An improved JPVM approach is proposed that simplifies the optimization process and enhances sound field control accuracy by discarding the tangential velocity component.

Findings

Discarding tangential particle velocity improves sound field reproduction.

The improved method offers better performance and lower complexity.

Sensor noise impacts are quantitatively assessed.

Abstract

In this paper, a recently proposed approach to multizone sound field synthesis, referred to as Joint Pressure and Velocity Matching (JPVM), is investigated analytically using a spherical harmonics representation of the sound field. The approach is motivated by the Kirchhoff-Helmholtz integral equation and aims at controlling the sound field inside the local listening zones by evoking the sound pressure and particle velocity on surrounding contours. Based on the findings of the modal analysis, an improved version of JPVM is proposed which provides both better performance and lower complexity. In particular, it is shown analytically that the optimization of the tangential component of the particle velocity vector, as is done in the original JPVM approach, is very susceptible to errors and thus not pursued anymore. The analysis furthermore provides fundamental insights as to how the spherical harmonics used to describe the 3D variant sound field translate into 2D basis functions as observed on the contours surrounding the zones. By means of simulations, it is verified that discarding the tangential component of the particle velocity vector ultimately leads to an improved performance. Finally, the impact of sensor noise on the reproduction performance is assessed.