Acoustic contrast control for sound fields outside and inside an enclosure

Loudspeaker arrays are commonly used for personal audio systems. Alternatively, panel loudspeakers can be employed in place of conventional loudspeaker arrays. The advantage of panel loudspeakers is that they preserve the appearance and aesthetic quality of products. Specifically, structural actuators can be mounted on the rear side of a product enclosure and thus remain concealed. However, directivity control on the front side may be undesirably accompanied by sound leakage on the rear side because the enclosure acoustically couples the two sides. To address this issue, acoustic actuators, i.e., loudspeakers, are introduced inside the enclosure and used in conjunction with the structural actuators. The array signal processing of the structural and acoustic actuators is based on acoustic contrast control, which simultaneously aims to achieve directivity control in the exterior space and sound reduction in the interior space. The performance of the proposed methods is verified through computer simulations and experiments using a rectangular plate-cavity model.