The present study evaluates the effectiveness of active sound transmission
control inside an enclosure using a purely acoustic source under the potent
ial energy, squared pressure, and energy density control algorithms. Full c
oupling between a flexible boundary wall and the interior acoustic cavity i
s considered. Formulas based on the impedance-mobility approach are develop
ed for the active control of sound transmission with the energy density con
trol algorithm. The resultant total acoustic potential energy attenuation a
nd sound fields under the three control algorithms are compared. Global amp
lification of the sound level with localized quiet zones under the squared
pressure control is observed. This adverse effect can be removed by using t
he energy density control. It is also shown that the energy density control
provides a more uniform control of sound field. Better performance of glob
al and local control of sound field using the squared pressure and energy d
ensity controls can be achieved by locating the error sensors at the peak q
uiet zones and the areas of peak energy density attenuation, respectively,
obtained under potential energy control. (C) 2001 Acoustical Society of Ame
rica.