Abstract: An electroacoustic transducer converts an electric signal into sound by vibrating a diaphragm magnetically in response to the electric signal input thereto. A movement restricting means for restricting the movement of the diaphragm within an allowable movement range is provided on the inner wall of a resonant chamber disposed at one side of the diaphragm. The restricting means normally confronts at a magnetic member attached to the center of the diaphragm. The restriction means contacts the magnetic member when the diaphragm attempts a deflection beyond the allowable range.

Abstract: The present invention provides a sounding apparatus with surface-mountable terminals, the sounding apparatus being capable of being automatically assembled onto a printed circuit board by the use of surface-mounting method. The sounding apparatus is formed by joining a molded housing including a pole piece and surface-mountable terminals to a container having sound emitting ports formed therein. A bobbin about which a magnet wire is wound is mounted on the pole piece of the housing and serves to actuate a vibrating plate spaced therefrom by a predetermined distance under the action of magnetic force. The bobbin includes bobbin terminals electrically connected with the terminations of the magnetic wire. When the bobbin is mounted on the pole piece, the bobbin terminals are brought into contact with the surface-mountable terminals on the housing so that the magnet wire on the bobbin will be electrically connected with the surface-mountable terminals.

Abstract: Disclosed is an electroacoustic transducer which comprises a diaphragm including an elastic plate, an added mass secured to a center portion of the elastic plate. The added mass has a contact portion, which contacts the elastic plate and is shaped to provide a portion to allow for deformation of the elastic plate within an imaginary circle defined by connecting an outer surface portion of the contact portion. Thus, the contact portion can provide a deformable elastic-plate portion within that circle. In other words, it is possible to accomplish such a structure obtained as if by connecting different springs having different spring characteristics, located outside and inside the circle. This structure can suppress and stabilize a variation in resonance frequency (f.sub.0) caused by a change in the amplitude of the diaphragm. The follow-up reproducibility of an output to an input is thus improved enough to cope with the case of using the electroacoustic transducer for AM sounds or attenuating sounds.