Abstract: An electromagnetic sound generator has a case provided with a yoke, a magnet, a vibrating plate and a coil, and a pair of leads. An end of the coil and the other end of the leads is secured to the case so as to be connected to an outside terminal. A terminal connecting device is provided for connecting the end of the lead to the outside terminal. The terminal connecting device comprises a cylindrical case secured to the case, a connecting rod slidably mounted in the cylindrical case, and a coil spring provided in the cylindrical case to outwardly urge the connecting rod so as to be contacted with the outside terminal at an end of the rod. A top end of the cylindrical case is contacted with the end of the lead.

Abstract: An electromagnetic sound generator has a vibrating plate mounted in a case. An armature is secured on the vibrating plate at a central portion thereof. The armature has a concave spherical shape.

Abstract: Disclosed is a communication buzzer.

Abstract: A metal base assembly for speaker that combines with a magnetic circuit to produce a fluctuating magnetic field which drives an acoustic diaphragm into vibration to produce a warning alarm. The metal base assembly comprises a top pad, a middle pad, a bottom plate, positioning rivets, a magnetic plate and a metal plate. The positioning rivets couple the top pad, the middle pad and the bottom plate together forming the metal base assembly with a recess cavity for accommodating the magnetic plate and the metal plate. Under influence of a magnetic force generated by a circular magnetic field generator, an acoustic diaphragm inside the speaker is made to vibrate rapidly producing a high tone warning alarm.

Abstract: A buzzer assembly for a personal communications device changes geometry in order to emit sounds at a variety of frequencies at an approximately constant volume, such as for playing melodic alerts. The buzzer assembly incorporates a buzzer and gasket to create an air chamber with an associated acoustic impedance. A translational actuator moves a portion of either the buzzer or gasket, depending on the particular embodiment, to change the air volume and thus the associated acoustic impedance. By changing the acoustic impedance, the resonant frequency of the buzzer assembly is changed. When the buzzer is then operated at or near resonant frequency corresponding to the then-current acoustic impedance, the sound generated by the buzzer assembly is louder.

Abstract: The present invention purposes to realize an electro-mechanical and acoustic transducer capable of generating both strong vibration and sound. In an electro-mechanical and acoustic transducer of the present invention, mass of a mechanical vibration system of the electro-mechanical and acoustic transducer is increased by attaching a weight to a magnetic circuit unit or integrated the weight with the magnetic circuit unit, whereby large vibration is obtained from the electro-mechanical and acoustic transducer.

Abstract: A device for regenerating powerful acoustic pressure comprises at least an arrangement for generating sound while utilizing the flextensional technique, i.e. having at least one surface element (2), the opposite ends (4, 5) of which are arranged to be influenced to oscillate away from and towards each other, and the surface element oscillating transversely thereto and generating sound.

Abstract: A method and circuit for emulating a contact breaker in trumpets having an inductor coil powered from a battery through a power driver device. The method includes obtaining the derivative of the current value flowing through the inductor of the trumpet coil, sensing a change in the slope of this derivative, and turning off a circuit portion of the driver device upon a negative slope being sensed. The circuit portion is turned back on with a transient of predetermined duration.