The objective is to use active control to suppress the acoustic energy that is radiated to the farfield from a structure that has been excited by a short duration pulse. The problem is constrained by the assumption that the farfield pressure cannot be directly measured. Therefore, a method is developed for estimating the total radiated energy from measurements on the structure. Using this estimate as a cost function, a feedback controller is designed using linear quadratic regulator theory to minimize the cost. Computer simulations of a clamped‐clamped beam show that there is appreciable difference in the total radiated energy between a system with a controller designed to suppress vibrations of the structure and a system with a controller that takes into account the coupling of these vibrations to the surrounding fluid. The results of this work provide a framework for a general, model‐based method for actively suppressing acoustic radiation that can also be used to deal with steady, narrow or broadband disturbances. [Supported by DARPA/ONR and AFOSR.]