The sound radiation from an elastically supported circular plate in an infinite baffle, which is excited by a concentric voice coil, was discussed taking account of the reaction of the acoustical fluid. Eigenvalue, elgenfunction, and volume velocity of each mode of the plate with different edge stiffness were calculated. It was found that the effect of elasticity was smaller for higher order of modes. There was a remarkable difference between the frequency response curves for light and heavy loading. For light loading(air), the peaks and dips were the results of resonances between the mass of the voice coil and the reactance of the mechanical impedance of the plate. On the other hand, for heavy loading(water), peaks and dips occurred when the reactance of mechanical impedance of the plate and radiation impedance canceled each other. The effect of several factors such as the loss factor of the plate, the mass and the radius of the voice coil on the frequency response curves were also discussed.