The surrounding structure of the loudspeaker forms an annular structure, including attaching parts and curved part. The cross section of the curved part is in a hollow and approximately elliptical form. The height along the major axis of the ellipse is made parallel to the center axis of the vibrating diaphragm of the loudspeaker while the width along the major axis of the ellipse is set in the direction orthogonal to the center axis of the vibrating diaphragm. In the elliptical surrounding structure having such a structure, the width in the cross section of the surrounding structure of the loudspeaker can be made narrow in comparison with a semi-circular surround, whereby the linearity of the amplitude and the maximum displacement are increased.

An annular surround for a loudspeaker cone wherein a radial cross-section of the surround varies around the circumferential extent of the surround, so as to accommodate peripheral expansion or contraction of the surround by bending. Thus a trough shaped cross-section of the surround may vary sinusoidally with angle around the polar axis of the surround between a semicircular and semielliptical cross-section. The trough section may bland to an adjacent portion of the surround by a fillet which also varies sinusoidally in cross-section in phase with the variation of the trough.

An economical and compact flat panel loudspeaker is disclosed that effectively dampens undesirable standing waves that form in the diaphragm without adversely affecting the frequency response. The diaphragm is preferably anisotropic, and has at least one compliant compressed dampening member transposed between it and a substantially planar support. The dampening member is preferably positioned at or near at least one mode of constructive or destructive interference on the diaphragm, and urges the diaphragm away from the planar support, thereby placing as light bending force on the diaphragm, and a slight compression force on the dampening member. Accordingly, the dampening member serves as a sink for transferring undesirable standing waves from the diaphragm to the planar support. In a preferred embodiment, the dampening member is an elongated strip of compliant foam rigidly secured to the diaphragm and planar support and extending through a plurality of modes on the diaphragm. The loudspeaker can include a plurality of dampeners with each dampener having different compliance characteristics. Alternatively, one or more dampeners can have layers of different compliance.

For transducers such as loudspeakers and actuators which must operate at unusually low or high ambient temperatures, a robust resilient annular support member for mounting the vibratable diaphragm extends outwardly therefrom to the main frame. The support member is formed from silicone elastomer or a silicone rubber composite in a molding process which may be a constant temperature process, preferably transfer molding. A diaphragm and a surround member may be bonded together in the molding process by inserting the edge of the diaphragm into the cavity mold. The molding techniques of silicone rubber composites containing pulp and weave fiber grades of commercially available mix materials allow transfer, compression or injection molding of diaphragm suspension system members with good control of the mechanical properties and thickness. Particularly with regard to surround suspensions, the ability to mold silicone rubber composite in thin cross sections and to vary the thickness and undulation pattern in the resilient region adds a great degree of design freedom.

A speaker includes a diaphragm, a frame accommodating the diaphragm and an edge attached to an outer periphery of the diaphragm as well as to an inner periphery of the frame so as to retain the diaphragm within an interior of the frame. The edge has a thickness which is smallest at substantially a central portion between the diaphragm and the frame and the vicinity thereof, and increases toward the diaphragm and the frame.