Vibration field rendering for a point-excited rectangular panel speaker

Abstract

A point excitation to a rectangular plate is often used to convert it as a panel speaker. However, the rectangular radiator has a disadvantage in invoking the high order vibration modes even at very low frequencies, thus deteriorating the sound quality. Furthermore, it can suffer a lengthy transient response when the plate subject to an external impact has a small damping. An inverse rendering for generating a virtual speaker, circularly shaped, is the study object in this work. The virtual speaker system is comprised of a circular speaker zone, excited at a center point, and a surrounding baffle zone. The system is controlled by an array of actuators, which is equivalent to find the proper gain for the actuator by solving the inverse problem consisting of the transfer matrix between array actuator and interior points. Two kinds of control array configuration are tested: a circular and rectangular array surrounding the main excitation point. The preliminary test indicates that the circular array results in better control performance than the rectangular one. The characteristics of control performance are also investigated by changing the parameters of the actuator array and the excitation frequency to obtain a strategy for realizing the most efficient panel speaker.