Department of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
J Acoust Soc Am. 2011 Oct;130(4):1926-35. doi: 10.1121/1.3624823.
Active control of sound can be employed globally to reduce noise levels in an entire enclosure, or locally around a listener's head. Recently, spherical loudspeaker arrays have been studied as multiple-channel sources for local active control of sound, presenting the fundamental theory and several active control configurations. In this paper, important aspects of using a spherical loudspeaker array for local active control of sound are further investigated. First, the feasibility of creating sphere-shaped quiet zones away from the source is studied both theoretically and numerically, showing that these quiet zones are associated with sound amplification and poor system robustness. To mitigate the latter, the design of shell-shaped quiet zones around the source is investigated. A combination of two spherical sources is then studied with the aim of enlarging the quiet zone. The two sources are employed to generate quiet zones that surround a rigid sphere, investigating the application of active control around a listener's head. A significant improvement in performance is demonstrated in this case over a conventional headrest-type system that uses two monopole secondary sources. Finally, several simulations are presented to support the theoretical work and to demonstrate the performance and limitations of the system.
声音的有源控制可以全局使用，以降低整个封闭空间的噪声水平，或者在听众头部周围局部使用。最近，球形扬声器阵列已被研究作为多通道声源，用于局部有源控制声音，提出了基本理论和几种有源控制配置。本文进一步研究了使用球形扬声器阵列进行局部有源控制声音的重要方面。首先，从理论和数值上研究了在远离声源处创建球形安静区的可行性，结果表明这些安静区与声音放大和系统鲁棒性差有关。为了减轻后者的影响，研究了围绕声源的壳形安静区的设计。然后研究了两个球形声源的组合，目的是扩大安静区。这两个声源用于产生环绕刚性球体的安静区，研究在听众头部周围进行有源控制的应用。在这种情况下，与使用两个单极次声源的传统头枕式系统相比，性能得到了显著提高。最后，提出了几个模拟结果，以支持理论工作，并演示系统的性能和局限性。
