Optimized nonlocal active sound control with preservation of desired sound field

Abstract

In this study we implement nonlocal active sound control to shield a bounded domain from ambient noise generated outside. This technique is practically applicable even if internally generated desired sound exists. Within the protected domain, the secondary field provided by the controls located at the perimeter neutralizes the external noise while preserving the desired sound unchanged. The generality of nonlocal active sound control facilitates its real-life application since only the total acoustic field at the boundary of the protected region is required as input data. The external noise and internal desired sound are automatically separated. We investigate the optimized distributions of sensors and controls to make this method more practically realistic. A series of numerical experiments are carried out, illustrating that significant noise attenuation can be achieved even with the sparse distribution of sensors and controls if the optimized distributions are implemented. The results also demonstrate that even two controls per wavelength enable to provide essential noise attenuation with optimized distributions.