2D Multizone Sound Field Synthesis with Interior-Exterior Ambisonics

Abstract

This paper presents a two-dimensional multizone sound field synthesis method based on sound field separation and interior-exterior higher-order Ambisonics (HOA) using two circular loudspeaker arrays. In the conventional methods using a circular loudspeaker array, multiple target local sound zones are represented as a global interior sound field. However, the control accuracy of the conventional methods is strongly dependent on the positional relationship between the wavefront direction in a bright zone and other dark zones. This is known as the occlusion problem. On the other hand, the global sound field is defined as a mixture of the interior and exterior sound fields based on sound field separation in the proposed method. The separated global interior and exterior sound fields are then simultaneously synthesized via interior-exterior HOA using two circular loudspeaker arrays with a cylindrical baffle to avoid the forbidden frequency problem in exterior HOA. The results of computer simulations demonstrate that the proposed method using the two circular arrays can successfully avoid the occlusion problem and realize higher control accuracy than the conventional methods using a single circular array.