Abstract: An electroacoustic transducer apparatus of a type that it is inserted into a cavum concha upon use. The electroacoustic transducer apparatus of the invention is applied to a headphone of a so-called in-the-eart type or so-called inner-ear type. This headphone is provided with an air passage portion formed through an elastic ring member attached to the outer peripheral portion of the housing so as to communicate the inside and outside portions of a concave portion of the cavum concha upon use. Accordingly, a certain amount of sound escapes to the outside, thereby obtaining the acoustic characteristics of substantially the same level from a low band to a high band regardless of the size of the user's ears.

Abstract: A stereophonic reproduction system which improves an unnatural sound image localization at an asymmetric position relative to right and left loudspeakers. Deterioration in tone quality incidental thereto is improved by filters providing right and left channels with selected phase characteristics.

Abstract: An improved loudspeaker assembly for frequencies higher than approximately 6 kHz, i.e., a tweeter assembly, is disclosed. The tweeter assembly includes a dome tweeter driver for delivering high frequency sound to a listener, and a cylindrical housing for mounting the tweeter driver in a horizontal plane. A centrally located aperture is provided in the top surface of the housing for receiving the dome portion of the tweeter, and a plurality of concentric annular ridges are also provided, and are spaced outwardly from the tweeter dome. The annular ridges function to reflect sound energy transmitted off the dome structure, and are used to disperse the high frequency energy in a horizontal direction within the listening room.

Abstract: An elastic material such as rubber is employed as the material of a diaphragm and the diaphragm is constructed in such a state that tension is made to exist intrinsically therein, whereby the vibration of the diaphragm when the vibration is applied to it has a large amplitude at the center thereof, gets smaller when approaching the perimeter thereof and finally reaches zero at the edge portion. Accordingly, almost no phenomenon occurs in which air in front and air in the rear of the diaphragm interfere with each other, a speaker box is not required and a tone of good quality may be reproduced.

Abstract: In a speaker unit having a voice coil bobbin, a diaphragm and a damper, the voice coil bobbin is integrally molded with at least one of the damper and diaphragm. The voice coil may be molded into the voice coil bobbin, and the brocade lead wires from the voice coil may be molded into the damper.

Abstract: The present invention provides an insert (1) forming an independent assembly of a coil body (15). The electroacoustic transducer comprises an insert (1) formed of a case with a vibrating membrane (2) and its electric connectors (4, 5) and a coil body (15) distinct and separable from the insert. The coil body can be fitted to the rear face (14) of the insert and comprises axial passages (20, 21) through which the insert connectors (4, 5) pass. Contact pieces (22, 23) provide the electric connection of the coil with the insert connectors.

Abstract: In the case of an electroacoustic transducer with a supporting body carrying coil turns and in particular a vibrating hollow body with a curved surface, such as a magnetostrictive ball, in order to obtain an optimum distribution of the modulation energy, it is proposed that the coil is applied to the supporting body (2) as a flat material corrugated strip (3) at right angles to the running direction.