Abstract: A speaker apparatus has a magnetic circuit portion, a diaphragm, a secondary coil, at least one primary coil, a cylindrical member, and a positioning portion. The magnetic circuit portion has a magnet, a yoke for which the magnet is provided, and a top plate for forming a magnetic gap together with the yoke. The primary coil is arranged in the magnetic gap of the magnetic circuit portion. The secondary coil is provided for the diaphragm so as to face the primary coil in the magnetic gap. One side of the cylindrical member locating in the magnetic gap is attached to the primary coil, and the cylindrical member supplies a current to the primary coil. The positioning portion is provided for a yoke and positions the other side of the cylindrical member.

Abstract: A loudspeaker (10) according to the invention is presented, which contains at least one radially magnetized permanent magnet (12), and whose receiving part is made of a paramagnetic or diamagnetic material. Such loudspeakers (10) can be constructed in a very simple and compact manner. With the further development of loudspeakers (10) able to utilize the stray flux from radially magnetized permanent magnets (12), it is possible to produce derivations with two diaphragms (13, 13′) with identical reproduction frequencies, without great cost.

Abstract: A loudspeaker having a flux gap defined by central pole and a magnet surrounding the central pole, includes a plurality of low-friction ridges extending from an outer surface of a the central pole. A voice coil, connected to the loudspeaker's diaphragm, is free to reciprocate within the flux gap. The ridges are linear and run generally in an axial direction, along a length of the pole where the voice coil reciprocates. Instead of rubbing directly against a metal pole, which has relatively high friction, the voice coil will rub against the ridges, thus reducing some of the noise that would otherwise occur due to rubbing. The voice coil includes a relatively stiff structure, created in part with a ceramic or epoxy material, that is coupled to a diaphragm, and a relatively flexible multiple layer structure at the terminating free end having dampening properties.

Abstract: A speaker apparatus for reproducing acoustic sounds includes a magnetic circuit unit having a substantially ring-shaped center plate of a magnetic material and a set of substantially annular magnets arranged on both sides of the center plate so that magnetic poles of repulsive polarities face each other with the center plate in-between. The magnetic circuit unit produces a magnetic field on each of an inner rim side and an outer rim side of the center plate. The speaker apparatus also includes a first vibrating system including a first vibrating plate arranged on the inner rim side of the center plate so as to be driven by the magnetic circuit unit, and a second vibrating system including a second vibrating plate arranged on the outer rim side of the center plate so as to be driven by the magnetic circuit unit. The first and second vibrating plates are substantially flat plate shaped and arranged so that their respective major surfaces lie on substantially the same horizontal plane.

Abstract: A speaker system includes a plurality of double-voice-coil speaker units fitted to a closed type cabinet and connected in parallel with each other so that first voice coils are connected to each other at the same polarities, and second voice coils are connected to each other at the same polarities, and a single impedance compensating circuit is connected in series to the second voice coils for making the input impedance as the speaker system constant.

Abstract: A fully integrated, low cost, amplified electro-acoustic loudspeaker is disclosed in which an amplifier circuit (30, 130, 230, 330, 930, 1030), radio-frequency receiver amplifier circuit (430, 530), optical receiver amplifier circuit (630, 730), or network based amplifier circuit (830) is directly mounted on the loudspeaker's magnetic assembly (105, 505, 705, 805), contained within the loudspeaker's moving assembly (20, 29, 629, 42, 45, 50, 65), or a combination thereof. The amplified loudspeaker's magnetic assembly (5, 105, 405, 505, 705, 805, 905, 1005) is utilized as an electro-magnetic interference shield and/or a heat dissipating element for the attached electronic circuitry. In selected embodiments of the amplified loudspeaker system, the former (42) containing voice coil (45) is additionally utilized for convection cooling of the amplifier circuit (30, 230) or receiver/amplifier circuit combination (430, 630).

Abstract: An electro-acoustic speaker having no permanent magnet. An audio input signal is applied to a pair of parallel coils, each being in series with a diode. The diodes are oppositely acting, so that the coils conduct during alternate half cycles of the input signal. As a result, the coils alternately generate magnetic flux for cooperative establishment of an unidirectional magnetic field. The input signal is also applied to a third coil for generation of a full wave current therethrough. This full wave current produces magnetic flux which establishes an alternating magnetic field. Interactions between the current-carrying coils and their respective magnetic fields produce acceleration forces for a speaker cone.

Abstract: An electromagnetic induction type acoustic transducer apparatus including a magnetic gap formed between a plate and a pole piece serving as assemblies of a magnetic circuit, a conductive ring attached to a diaphragm, the diaphragm interposed within the magnetic gap for generating sounds when it is vibrated, and a flat coil disposed in the plate or the pole piece at the position opposing the magnetic gap and of which winding is increased from the vibration direction of the diaphragm to the direction perpendicular to the vibration direction of the diaphragm, wherein a width of the magnetic gap can be reduced.

Abstract: In a speaker system employing a bass reflex or Kelton type cabinet intends to solve deterioration in efficiency of a speaker caused by an increase in impedance otherwise occurring on both sides of the antiresonance frequency, and to improve the sound radiating efficiency. The speaker system comprises a plurality of dual-voice-coil speaker units (20) which are attached to a bass reflex or Kelton type cabinet (50) and made up of first voice coils (21) connected in parallel to each other with the same polarities joined into one terminal and second voice coils (22) connected in parallel to each other with their same polarities joined into one terminal, and one impedance compensation circuit (10) connected in series to the plurality of second voice coils, which are connected in parallel to each other, for thereby keeping constant the input impedance as a parameter of the speaker system.

Abstract: An electromagnetic induction type acoustic transducer including a plate as an assembly of a magnetic circuit and having an opening of a predetermined diameter about a central axis, a pole piece as an assembly of the magnetic circuit and protruded on the central axis, having an outer peripheral diameter smaller than the opening of the plate and having an upper surface located lower than a lower surface of an opening peripheral portion of the plate by a predetermined distance, a lower surface portion of the opening peripheral portion of the plate and an upper surface portion of the pole piece constitute a magnetic gap of the magnetic circuit,a diaphragm vibrated in the upper and lower direction on the central axis at the position perpendicular to the central axis in the predetermined distance, an annular ring attached to the diaphragm at the position of the magnetic gap, and a coil attached to the plate and/or pole piece.

Abstract: A loudspeaker has a chassis, a cone, an actuator and a sub-frame. The actuator is coupled between the chassis and the diaphragm. The sub-frame is flexibly coupled to the chassis and the diaphragm. The diaphragm is flexibly suspended from the chassis. The actuator directly drives both the diaphragm and the sub-frame through coils attached to the cone and to the sub-frame.

Abstract: The planar magnetic continuous-tone transducer functions as a low power, wide dynamic range speaker. The planar magnetic continuous-tone transducer uses a conventional pair of ferrite cores on which are tightly wound primary and secondary coils. A very small air gap is provided between the two ferrite cores and the secondary coil is left unterminated. The application of a voltage at a selected frequency to the primary coil induces a harmonic force in the open secondary coil, which is transmitted to the two ferrite cores. The harmonic force causes the ferrite cores to vibrate, emitting a tone from the air gap region.

Abstract: An electromagnetic transducer diaphragm having an electrical conductor layer, with a conductor pattern, positioned between two insulating layers of a flexible, electrically-insulating material bonded together to protect the diaphragm. An electrical current can flow through the conductors to produce magnetic and electrostatic fields around said conductors which interact with an electromagnetic field to produce mechanical displacement of the diaphragm which in turn produces an audio signal. Non-ferrous supports can be used to support the diaphragm. A magnet or magnets may be used to create the electromagnetic field. The magnets can be bonded to the cross arms of the non-ferrous support.

Abstract: A spacer for mounting around the outer peripheral surface of a bobbin. The spacer has first and second edge surfaces formed in a circular arc shape. Subsequent to the formation of a first coil by winding wire around the bobbin, the wire is continuously curved from a distal end portion of the first coil along the first edge surface of the spacer. After making a U-turn of substantially 180 degrees, the wire is wound to form the second coil. Upon completion of winding of the second coil, the wire is guided along the second edge surface, from an end portion of the second coil, and a second portion of the first coil is wound. The portion of the wire for connecting both of the first and second coils is free from bent corners, thus avoiding the generation of stress concentration. Also, the wire is guided by smooth and curved edge surfaces of the spacer, thus preventing damage to a coating on the wire.

Abstract: A speaker apparatus which drives an electromagnetic-coupling-type speaker in accordance with a digital signal is provided with a speaker unit, and a plurality of amplifiers corresponding to the number of quantization bits of a digital audio signal. The output terminals of the amplifiers are connected to the respective primary coils, respectively, and the output impedances of the plurality of the amplifiers are made equal to those of the respective primary coils to which the amplifiers are connected. Each bit of each sample of the digital audio signal is amplified by the plurality of the amplifiers and supplied to the respective primary coils, respectively.

Abstract: A light and cost effective speaker is provided which is suitable for a vehicle mount speaker, thin, and has a broad reproduction frequency band. Like a cone diaphragm and a center cap or the like, the cone diaphragm having a valley at the junction point with the center cap is integrally mounted with the center cap, and a plurality of voice coils, preferably three or more voice coils, are radially disposed along the valley or at the area near the valley to drive the diaphragm.