Optimal Design of Exciter Array to Minimize Bending Mode Effect of Multi-Actuator Panels in Beamforming

Recently, flat-panel loudspeakers have been applied to many product designs as a way to solve space constraints when installing speakers. In addition, multi-actuator panels with multiple exciters on the panel can be used for sound field control such as sound field synthesis and beamforming, instead of conventional cone-type loudspeaker arrays. At this time, the bending mode of the panel adversely affects the control performance. Conventional multi-actuator panel solves this problem by using a panel having a large damping loss factor. However, it is difficult to apply this method when the material properties or geometry of the structure cannot be changed. In this regard, this study aims to minimize the bending mode effect of the panel on beamforming performance through the optimal exciter array design. Vibration localization factor is used to investigate the bending mode effect of the panel. Simplified forms of vibration localization factor based on mode frequency and modal participation factors are used to optimize the exciter position. The optimized exciter array design minimizes the bending mode effect of the panel in a controllable