a new hybrid optimization method including of simplex method and method of design of experiments is developed. The objective of the optimization includes the minimization of the root mean square level of structure borne sound. Application of this new hybrid optimization method is experienced on a square plate. The shape modification concept is considered. The structure’s local geometry modification values at the selected surface key-points are considered as design variables. It is shown that the presented hybrid optimization method is able to reduce the value of objective function with a few number of objective function evaluations.