Sound fields in a rectangular enclosure under active sound transmission control

The present study evaluates the effectiveness of active sound transmission control inside an enclosure using a purely acoustic source under the potential energy, squared pressure, and energy density control algorithms. Full coupling between a flexible boundary wall and the interior acoustic cavity is considered. Formulas based on the impedance-mobility approach are developed for the active control of sound transmission with the energy density control algorithm. The resultant total acoustic potential energy attenuation and sound fields under the three control algorithms are compared. Global amplification of the sound level with localized quiet zones under the squared pressure control is observed. This adverse effect can be removed by using the energy density control. It is also shown that the energy density control provides a more uniform control of sound field. Better performance of global and local control of sound field using the squared pressure and energy density controls can be achieved by locating the error sensors at the peak quiet zones and the areas of peak energy density attenuation, respectively, obtained under potential energy control.