This paper proposes designing an optimal static output feedback controller for a structural-acoustics coupled system as efficient control architecture. Modelling of sound transmission through a plate-cavity-plate system is presented. In this coupled structural acoustic system, an approximate series solution is assumed for the displacements of the plates and the pressure inside the cavity. The solution of the coupled system is obtained using Galarkin's method. The system to be modeled is consisting of a rectangular cavity with two flexible plates, one at the top of the cavity while the other at the bottom and four other fixed boundaries. Piezoelectric pair patches are considered to be bonded to the top plate, and each
pair is assumed to produce a pure moment actuation. The top plate is exposed to an external pressure excitation due to a planar wave generated by a sound source mounted above the cavity. Displacements at the mid points are calculated for the upper and lower plates. In the control scheme, the controller gains have been optimally tuned using genetic algorithms. The proposed architecture is compared to the linear quadratic Gaussian state feedback controller. The two controllers are compared for the time responses. The proposed controller shows a superior performance with simple implementation requirements.