Most analyses of loudspeaker performances are based primarily on the consideration of details of the electromechanical coupling. This approach has proved too inadequate to handle loudspeaker radiation problems. An attempt has been made to set up a general expression relating the free field sound pressure at a remote point to the electrical signal applied to the loudspeaker terminals. This relation in the form of an integral equation is solved exactly for a loudspeaker of circular shape. By means of the solution of the integral equation it appears possible to apply to this problem methods analogous to circuit analysis techniques which represent the transfer function of the system in terms of its characteristic points in the complex frequency plane.