This paper is concerned with the numerical study of active control of interior noise induced by the flexible plates in a coupled enclosure. A cabin-like enclosure with four acoustically rigid walls and two flexible plates is considered. Two types of actuators are used, i.e. acoustic actuators and distributed lead zirconate titanate piezoelectric (PZT) actuators instead of point force actuators. With the control system designed to globally reduce the sound field, different control configurations are considered, including the structural actuator on the incident panel, actuator on the receiving panel, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control system corresponding to each configuration are studied numerically, and desirable placement problem of structural actuators in terms of total potential energy reduction are of particular interest.