Investigation of Excitation Methods in Active Control of Sound Transmission through a Thin Planar Structure

This study deals with the active control of sound transmission through a thin planar structure. The effect of the active sound transmission control depends significantly on the methods used to excite the structure, such as the location of the actuators. However, the principle to determine the excitation method has not been revealed clearly thus far. In this study, the methods used to excite a panel with point actuators for active sound transmission control in the case of normal incidence are investigated by simulations. Further, various actuation methods using point actuators, e.g., center-point control, four-point control, sixteen-point control, etc., are compared. On the basis of the simulation results, we propose an effective excitation method in which the point actuators are located on the nodal lines at frequencies slightly less than the resonant frequencies of the panel at which the transmitted sound power significantly decreases. Then, it is shown that the proposed method can suppress both the transmitted sound and vibrations in a low-frequency range. Finally, experiments are carried out to confirm the simulation results and the validity of the proposed method.