Abstract: In a loudspeaker device of the present invention, an interior space of a cabinet 20 is parted into first and second chambers Wb1 and Wb2, a diaphragm 23 on which ring-shaped magnetic boards 29a and 29b are fixed is attached to a parting board 22 via an edge portion 24, and ring-shaped fixed magnets 25 and 27 are provided so as to face magnetic boards 29a and 29b, respectively. Vibration of the diaphragm 23 vibrated by sound pressure from a speaker unit 21 is intensified by forces of attraction of the magnets 25 and 27 in order to reduce an acoustic stiffness of the cabinet 20 and equivalently increase a cabinet volume, thereby realizing satisfactory bass reproduction with a small cabinet.

Abstract: A magnetic circuit includes an annular magnet magnetized in the axial direction thereof; an annular stacked plate disposed on the magnet and including first and second annular plates; and a yoke facing the inner circumferential surface of the stacked plate across a cylindrical space. Upper and lower magnetic gaps are provided at two axially separated positions in the cylindrical space. A loudspeaker includes the magnetic circuit; a voice coil placed in the upper and lower magnetic gaps; a diaphragm connected to the voice coil; and a frame fixed to the stacked plate and supporting the diaphragm in a vibratable manner. The inner circumferential portions of the first and second annular plates are axially deformed downward and upward, respectively, such that the inner circumferential surface of the stacked plate faces the lower and upper magnetic gaps. The remaining portions of the first and second annular plates are stacked on the magnet.

Abstract: Speaker design/method positively centering speaker components one with the other with a unique design of the surround and radiator. Surround has a main body extending radially through more than 180°, extending from the body there is a flat outer ring and a flat inner ring at substantially 180° radially around the body from the outer ring with a portion of the main body extending below the inner ring, forming a channel between the inner ring and the body portion that extends below it. The radiator has outer and inner edges with a central opening defined by the inner edge, with the outer edge either blunt or defined by a short downward extending ring. The shape and dimensions of the outer edge of the radiator and the channel are substantially the same outer with the radiator edge fitting snugly within the surround channel.

Abstract: A lead wire of a voice coil is wired along the surface of a diaphragm. The lead wire is bent toward a reverse side of the diaphragm at a peripheral edge portion of the diaphragm. The lead wire is led to the interior of a frame. An external terminal is provided to extend from outside to inside the frame. In addition, a connecting portion for connecting the lead wire and the external terminal is provided inside the frame. The connecting portion is prevented from coming into contact with another part and becoming short-circuited.

Abstract: A sound reproducing system using sound pressure is disclosed. The sound reproducing system is constructed in such a manner that the conductive wire is arranged in multiple rows or columns and the gap between neighboring parts of the arranged wires is sealed up by a thin film alternately. In addition, sound pressure generated by a sound pressure generator passes through the gap between neighboring wires that is not sealed up and the wires are vibrated around the thin film so as to change the sound pressure, thereby reproducing sound.

Abstract: The micro-speaker includes a driver unit having a housing, a magnet disposed within the housing forming a radial gap between the magnet and the circumferential walls of the housing, and a magnetic plate disposed on the magnet, a vibration system having a diaphragm and a voice coil where the vibration system is fixed to the drive unit and the voice coil protrudes into the radial gap, and a volatile magnetic fluid in the radial gap about the voice coil.

Abstract: An electromagnetic transducer such as an audio speaker, having a tube geometry motor which is not axisymmetric. The tube geometry motor includes a tubular yoke of soft magnetic material. The tube includes an air gap hole through a wall of the tube. A pole piece extends through the air gap hole to define the magnetic air gap between the tube wall and the pole piece. A hard magnet is coupled to the tube. In some embodiments, the pole piece is coupled to a back plate inside the tube, which in turn is coupled to the hard magnet. A diaphragm assembly is coupled to the outer side of the tube. The axis of movement of the diaphragm assembly and the extruded axis of the tube motor are perpendicular. Different models of the transducer motor can be fashioned by increasing the magnetic flux over the magnetic air gap, without having to make the motor wider or deeper, and without requiring new tooling for the tube, simply by making the motor longer and longer along the extruded axis.

Abstract: The present invention relates to a multifunctional device, which is particularly applicable to a twin magnet loop (called TML) transducer with both vibrating and sound functions. The present invention integrates an inner and an outer magnet loop of TML into one device, which can be used as a vibrator and a speaker. A disc-shaped pole core, a flange bowl-shaped magnetic transfer, an annular pole piece, a cylindrical magnet and an annular magnet constitute the inner and outer magnetic loops; wherein the disc-shaped pole core is placed on the cylindrical magnet and centered with the flange bowl-shaped magnetic transfer; the annular magnet and the annular pole piece are overlaid together under the ring of the flange bowl-shaped magnetic transfer; the entire of the TML assembly is connected with a housing base via a resilient plate.

Abstract: To reduce the effects of disturbing electromagnetic effects on a loudspeaker of a mobile telephone, the loudspeaker is provided with a compensation coil in addition to an excitation coil. The compensation coil is series-connected with the excitation coil. However, it is dispensed of the need for playing a driving role by being bonded to the permanent magnet of the loudspeaker. It is shown that the harmful effects are reduced without stopping the loudspeaker from working.

Abstract: There is a terminal block with leaf spring metal terminals that extend downward from a housing on the side opposite the open end of the housing in which a diaphragm is fitted and fixed, and an elastic material functions as a pad that is sandwiched between the surface of a circuit board and the open side of the housing on the side from which the metal terminals project, with the metal terminals pressed against the conduction pattern of the circuit board to make an electrical connection.

Abstract: Ring magnets (5) are concentrically placed with certain spacings (6) on a magnetic frame (4). The magnetic members on the magnets (5) are removed, and the magnets are arranged so that the polarities of adjacent magnets (5)are alternately opposite to each other, thus forming a magnetic circuit. Ribs (7) are provided to a planar vibrating plate (1) and a voice coil (2) fabricated by vertically stacking conductive wires annularly is attached to the planar vibrating plate (1). The planar vibrating plate (1) is secured to a frame (4) through a gasket (3). The voice coil (2) is inserted into magnetic gaps of spacings (6). Since no magnetic body is placed over the magnets (5), the height of the magnetic circuit can be low, and an increase of the reactance due to provision of the magnetic body of the voice coil (2) does not occur. Since the rigidity of the planar vibrating plate (1) is high, it is unnecessary to secure the planar vibrating plate (1) to the frame (4). while applying a tension.

Abstract: The method of assembling a micro-speaker includes disposing a quantity of volatile magnetic fluid into a radial gap of a driver unit, aligning a vibration system having a diaphragm and a voice coil to the driver unit such that the voice coil is accommodated into the radial gap, fixing the vibration system to the driver unit, and removing the volatile component of the volatile magnetic fluid. The micro-speaker includes a driver unit having a housing, a magnet disposed within the housing forming a radial gap between the magnet and the circumferential walls of the housing, and a magnetic plate disposed on the magnet, a vibration system having a diaphragm and a voice coil where the vibration system is fixed to the drive unit and the voice coil protrudes into the radial gap, and a volatile magnetic fluid in the radial gap about the voice coil.

Abstract: An electroacoustic transducer 1 includes a base 24 made of a magnetic material; a magnetic core 22 made of a magnetic material and upstanding on the base 24; a diaphragm 20 made of a magnetic material and spaced from a leading end of the magnetic core; a magnetic field generating member 25 cooperating with the base 24, the magnetic core 22 and the diaphragm 20 to constitute a magnetic circuit, for supplying a static magnetic field; a coil 23 placed around the magnetic core, for supplying an oscillating magnetic field to the magnetic circuit. The magnetic field generating member 25 constitutes a multiplex ring structure in which a magnet 25a and a support ring 26 are integrated together, whose faces opposing the diaphragm 20 have respectively magnetic poles of the same polarity.

Abstract: In manufacturing a speaker, ultrasonic complex vibration welding is applied at least to: a process of fixedly putting together a magnet, a pot yoke a the pole piece; a process of fixing, to a portion of an inner circumference of a frame, an outer periphery of a spider, which has its periphery fixed to a bobbin; a process of fixing to a portion of the frame an outer circumferential edge of a surround, which has its inner circumferential edge fixed to an outer periphery of a diaphragm whose inner periphery is fixed to the bobbin; and a process of fixedly connecting both ends of each of tinsel leads respectively to terminations of a voice coil and to terminals.

Abstract: The present invention provides a transducer for converting between mechanical vibration and electrical signal, the transducer comprising a housing enclosing a substantially cylindrical permanent magnet and a coil, the magnet having a side-to-side polar orientation. The transducer may be used as sensor that is part of a sensor array for detecting vibrations from a hollow-bodied musical instrument and converting the vibrations into electrical signals for amplification.

Abstract: In an electromagnetic induction type speaker apparatus, individual constants are set in such a manner that the following formula is satisfied

Abstract: A speaker has a frame provided with a yoke, a magnet, a vibrating plate and a voice coil, and a pair of leads. An end of each of the leads is connected to an end of the coil and the other end portion of the lead is exposed in a hole formed in the frame and secured to the frame so as to be connected to an outside terminal. A terminal connecting device is provided for connecting the other end of the lead to the outside terminal. The terminal connecting device comprises a cylindrical case secured in the hole of the frame, 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 portion of the lead.

Abstract: The speaker comprises a ring-shaped frame 110, a magnetic circuit section 120, a vibration section 130, a terminal 140, a tinsel wire 145, and a weight ring 150. The ring-shaped frame 110 has a through hole formed in the center of thereof. The magnetic circuit section 120 is coupled to the outside of the through hole. The vibrating section 130 include a diaphragm 131 with an upper end coupled to the inner side of the through hole at the upper side of the frame 110, and a voice coil 133 having an upper end coupled to the diaphragm 131 and a lower end located in the magnetic circuit section 120. The tinsel wire 145 has one end connected to the terminal 140 and the other end connected to the voice coil 133. The weight ring 150 is coupled to the outer surface of the voice coil 133. With this configuration, the weight ring coupled to the voice coil allows the weight of the voice coil 133 to be increase.

Abstract: An information processing device and a speaker unit applicable to the device. In one aspect of the present invention, the device includes a housing, a pole piece, a voice coil, a magnet, and a frame. The housing has an elastically vibratory vibration region. The pole piece has a first end and a second end. The first end is fixed to the vibration region of the housing. The voice coil is fixed to the second end of the pole piece. The magnet forms a magnetic field interlinking the voice coil. The frame fixes the magnet to the housing at a region other than the vibration region, for example. With this configuration, vibration of the voice coil due to a current flowing through the voice coil is transmitted through the pole piece to the vibration region of the housing, thus eliminating the need for a vibration board of a speaker and further eliminating the need for formation of holes for sound transmission through the housing.

Abstract: A mid and high frequency transducer having a compact magnet system. A first seat has an annular wall that retains a first disk shaped magnet therein and an annular channel is defined therebetween. A second seat rests on top of the first magnet and first seat and is connected thereto but does not occlude the annular opening. The second seat has an annular wall that retains a second disk shaped magnet therein such that a uniform annular gap is defined therebetween. A first voice coil is connected to a first diaphragm and is moveably suspended within annular channel and a second voice coil is connected to a second diaphragm and is moveably suspended within the annular gap. Application of an electric current to the voice coils causes movement of the diaphragms due to the magnetic flux created within the annular channel and gap and thereby produces sound waves.

Abstract: A speaker device and associated method for producing a speaker device that includes a voice coil and a radiant layer made of a radiant energy emissive material provided on a surface of the voice coil for suppressing the heat generated at the voice coil while simultaneously improving the input durability of the speaker device.

Abstract: An acoustical speaker and planar magnetic transducer therefore wherein the transducer is provided with at least array of spaced magnets which are oriented having their pole faces at an angle with respect to a plane defining a surface of a sound producing diaphragm on which extends an electrical trace circuit.

Abstract: It is an object of the invention to provide an improved speaker apparatus which maintains the advantages as an inverted dome speaker and has a good directivity and a thin thickness, as well as a broad playback frequency band extending from a high frequency band to a low frequency band. The speaker apparatus includes a dome diaphragm carrying a voice coil and having a concave cross section protruding towards the voice coil, an edge provided on the outer periphery of the dome diaphragm, having a concave cross section protruding towards the voice coil, and supporting the dome diaphragm on a frame, and a magnetic circuit forming a magnetic gap containing the voice coil. Particularly, the edge has a broad edge width {b=(1.5-3)a} bearing a lower playback frequency band than a playback frequency band born by the dome diaphragm.

Abstract: A loudspeaker consisting of a diaphragm, a voice coil carrier secured to the diaphragm in a central area, a voice coil wound around said voice coil carrier, a magnetic system inserted into the voice coil carrier and voice coil in a partial or complete manner, a basket supporting the magnet system and enclosing the diaphragm on one face thereof, an elastic bead fastened to the basket and an edge area of the diaphragm, and a centering device attached to the basket and fastened to the diaphragm in a central area, said centering device being provided with an elastic bead that is directly or indirectly fastened to the basket and the diaphragm.

Abstract: A weight is attached to the rear side of a magnetic circuit of a speaker unit. The tip of a boss that projects to the front side from the weight is joined to the rear side of a center pole of the magnetic circuit with a bolt. Even if reactive force that is generated when an electrical signal is converted into mechanical vibration by the magnetic circuit and a voice coil and sound waves are emitted from a vibration plate is transmitted to the magnetic circuit, the vibration of the magnetic circuit is suppressed by the weight. In this manner, sound quality with a good transient characteristic can be obtained.

Abstract: The present invention provides an electroacoustic transducer capable of removing non-uniformity of a gap between a coil and a magnet and of vibrating a diaphragm properly, and an electronic apparatus using the same. An electroacoustic transducer 1 of the present invention comprises a plane diaphragm 2 and a vibration-generating source 3 for vibrating the diaphragm 2, wherein the vibration-generating source 3 is supported in the vicinity of one end 2a on the backside of the diaphragm 2, at least the one end 2a and two sides 2b and 2b of the diaphragm 2, which are perpendicular to the one end 2a and are opposite to each other, are supported on an elastic cushion member 9, and wherein the diaphragm 2 is vibrated in a plane direction perpendicular to the plane of the diaphragm 2 when the vibration-generating source 3 is driven.

Abstract: A speaker has a magnet structure mounted ahead of the speaker diaphragm to produce a shallow compact unit. The magnet structure defines a flux gap, and a voice coil residing in the flux gap is connected to a main diaphragm such that drive current applied to the voice coil moves the diaphragm to generate sound. The voice coil and magnet structure provide a flux gap at the rear of the magnet structure, ahead of and centered on the main diaphragm, while the magnet occupies space within the cone, freeing up space in the rear. In one embodiment, the magnet structure has an additional flux gap located at its forward end and the speaker includes an additional diaphragm driven by a coil positioned in the additional flux gap. The main diaphragm and additional diaphragm are better positioned to maintain a common sound center for enhanced spatial fidelity and different tuning techniques present a broad flat response below crossover to form a pinpoint sound source of wide angular coverage.

Abstract: Disclosed is a linear actuator which includes a core, a coil, a magnet assembly, and a housing. The coil that is shaped to be positioned about the core for movement along a longitudinal axis of the core. The housing is supported by core flanges and positioned about the coil and the core. The magnet assembly includes magnets of the same polarity facing the coil and shaped to be positioned inside or outside of the coil, and supported by the core or by the housing, respectively. The core includes first and second portions, each having an end face, and the first and second portions are positioned along the longitudinal axis so that the end faces oppose each other and are separated by a gap. A cavity is formed in each of the end faces along the longitudinal axis.

Abstract: An electromagnetic transducer such as an audio speaker, having an improved geometry in the positioning of its voice coils relative to its magnetic air gaps, facilitating a greater linear travel. The transducer has a push-pull geometry with at least two voice coils. At all positions throughout the linear travel region, less than 100% of the total voice coil windings are active, and less than 100% of the total available magnetic air gap height is active. As the voice coil assembly moves in one direction, the percentage of active windings or magnetic air gap is seamlessly handed off from the upper voice coil or magnetic air gap to the lower voice coil or magnetic air gap, and vice versa in the opposite direction. Some of the available voice coil windings and some of the available magnetic air gap height are left unused throughout the linear travel region, but, in exchange, the distance of the linear travel is dramatically increased.

Abstract: An armature for a receiver includes a first leg portion, a second leg portion, and a connection portion in communication with the first and second leg portions. The connection portion reduces the stiffness of the armature and minimizes magnetic reluctance of the connection between the first and second leg portions.

Abstract: An elongated oval track-shaped loudspeaker has a diaphragm of a track-shape having major and minor axes, and a pole piece of an elongated oval shape and disposed to conform its major axis to that of the diaphragm, whereby a sufficient space is secured for a width size of a diaphragm-supporting damper at its portions on both sides along the major axis of the diaphragm, a magnet around the pole piece is enlarged, and the pole piece is dimensioned in its sectional area to correspond to the magnet to cause no magnetic saturation.

Abstract: An improved speaker having a modified front plate with air intake apertures, a vented frame, and a voice coil supported by a diaphragm constructed of gas impermeable material connected at one end to the frame and at the other end to the voice coil. Operation of the voice coil causes the diaphragm to draw air through the air intake apertures where it is drawn past the voice coil and vented out through the frame. The diaphragm operates as an air pump forcing the air past the voice coil for supplying of cool are and exhausting of heated air. A unidirectional flap may be used on the vented frame to an create air flow current past the voice coil for higher efficiency. The improved speaker provides longevity to the voice coil, the voice coil to diaphragm coupling, and to the diaphragm itself.

Abstract: A speaker includes: a frame; a magnetic circuit fixed to the frame; a diaphragm fixed to the frame so as to be capable of vibrating in a predetermined direction; a driving force transmitting member connected to the diaphragm; and a damper for supporting the driving force transmitting member, wherein the magnetic circuit is positioned between a first plane and a second plane, the first plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, and the second plane being parallel to the diaphragm and defined as a plane with which at least a portion of the magnetic circuit is in contact, and one end of the damper is connected at a position between the first and second planes, and the other end of the damper is connected at another position between the first and second planes.

Abstract: Loudspeakers and other transducers of the dual-voice-coil/dual-magnetic-gap type can be improved by the addition of one or more annular shorting rings strategically located in the vicinity of the two magnetic gaps. The shorting rings have no effect on a steady state magnetic field but act in opposition to any change in flux density or any displacement of the flux lines such as those that occur under the loading imposed when the voice coils are driven hard with audio frequency current. The location of the shorting rings determines their effect: location close to a voice coil reduces the voice coil inductance, location entirely within the magnetic flux loop centerline favors reduction of second harmonic and higher order even harmonic distortion, a centered location on the flux loop centerline, i.e.

Abstract: The described invention refers to a new type of loudspeaker module in the form of a ribbon element, designed in such a way that the module can be optionally equipped with a membrane, 50 millimeters in width or narrower, and with any length from 50 millimeters to 2500 millimeters.

Abstract: An electromagnetic transducer, such as an audio speaker, in which magnetic flux is provided to the drive magnetic air gap(s) by both an external permanent magnet (as in conventional pole plate geometry transducers) and an internal permanent magnet (as in conventional neo or cup geometry transducers). Both magnets may have the same polarity orientation, enabling them to be simultaneously charged after assembly of the transducer's motor structure. A lower one of the permanent magnets uses the yoke as its return path. A low reluctance return path is provided for the upper one of the permanent magnets to improve performance.

Abstract: A plurality of grooves are radially formed in an annular frame and an annular plate is secured to the frame to form a sound discharge hole in each groove, thereby communicating a back chamber under a diaphragm with the atmosphere. A projected part is outwardly projected from a peripheral edge of the annular plate, and an adhesive is adhered to a peripheral edge of a protector and to an upper surface of the projected part to adhere the protector with the annular plate.

Abstract: An electromagnetic transducer such as an audio speaker which includes an asymmetric diaphragm to deliver smooth frequency response with reduced distortion by reduction of common modes in the diaphragm. Other benefits such as asymmetric directivity patterns can be realized. The asymmetric cone has a perimeter OD at which a surround may be coupled, and an ID at which a bobbin or spacer may be coupled. The center of the ID is not coincident with the center of the OD. The transducer further includes a stabilization mechanism for reducing rocking of the diaphragm assembly. The stabilization mechanism may include mass balancing of the diaphragm and/or adjustments to the location or symmetry of the suspension components.

Abstract: A bobbin unit includes a base portion and a coil winding portion on which a conductor is wound. A hole is formed in a central part of the base portion to allow an armature to pass through. Coil side terminals to which ends of the conductor are fixed and signal input terminals to which an external signal is entered are provided at opposite ends of the base portion with the hole located in between. The coil side terminals are electrically connected to their corresponding signal input terminals inside the base portion. A coil is formed on the coil winding portion by winding the conductor. The ends of the conductor are fixed to the respective coil side terminals.

Abstract: A dual magnetic loop type receiver is composed of a yoke molding, a ferrite yoke, an annular magnet, a magnetic pole member, a vibration panel, a ferrite core, and a circular plate. While the receiver is operated, the annular magnet and the ferrite core and the ferrite yoke cause the receiver to produce an inner magnetic loop that interacts with the inner voice coil, and an outer magnetic loop that interacts with the outer voice coil such that the receiver generates vibration and sound.

Abstract: The present invention relates to an electromagnetic vibrator of variable reluctance type, according to a new principle which provides higher efficiency, smaller dimension, and higher reliability compared to known technology. This has been obtained by the magnetic signal flux around the coil is closed through a bobbin body and a yoke and through air gaps formed between bobbin body and yoke(s) where a static flux from one or more of the permanent magnets and the signal flux cooperates so that static forces are outbalanced and so that axial signal forces are generated. The new vibrator principle has been names: Balanced Electromagnetic Separation Transducer (BEST).

Abstract: In a speaker device 10 having: a magnetic circuit 13 including a magnet 14 and a yoke 11; a voice coil 16 which is placed in a magnetic gap 12 of the magnetic circuit 13; and a diaphragm 17 which is vibrating available in a state where the diaphragm is coupled with the voice coil 16, a peripheral edge of the diaphragm 17 being fixed to a housing 20, a damper holder 30 is disposed in a portion where a damper 27 is attached to the housing 20. The damper holder 30 is in point contact with the housing 20 via three or more projections 31 which are disposed on one of the damper holder 30 and the housing 20. Preferably, the damper holder 30 is made of a hybrid material of a resin (polypropylene) and tungsten, and has a specific gravity of 10.0 or larger.

Abstract: A speaker with enhanced magnetic flux loop includes a core magnet (12) installed inside hollow space of a bottom yoke (11), and a ring-shape magnet (13) with opposing polarity placed on the outer periphery of the core magnet (12). The ring-shape magnet (13) acts as an induction medium in a magnetic flux loop flowing across the core magnet (12), thus bottom yoke the magnetic flux within the boundary of the yoke (11) and preventing loss of magnetic flux. The dual magnet architecture brings about increased sensitivity to sound and output volume for the speaker, whilst the external dimensions of the conventional speaker can be scaled down as a result of smaller yoke (11).

Abstract: A loudspeaker with independent magnetic dampening and excursion control includes at least two magnets for dampening the axial movement of a voice coil. The dampening magnets substantially reduce/prevent fatigue of the component parts of the loudspeaker and detrimental contact between the voice coil and its supporting parts and the remaining component parts of the loudspeaker. A pole yoke supported by a backplate defines the inner diameter of an annular gap within which the voice coil moves and a top plate defines the outer diameter of the gap. A first dampening magnet is statically supported by the pole yoke. A second dampening magnet is supported by and moves in concert with the voice coil. As the voice coil and second magnet move within the gap, the repelling forces of the magnets provide the desired dampening effect, thus limiting or reducing the movement in one direction.

Abstract: A loudspeaker comprising a moving coil and a membrane fastened to a chassis, where the membrane is divided into a concentrically disposed inner membrane part and a concentrically disposed outer membrane part, whereby a meeting area is defined between the inner membrane part and the outer membrane part, the inner membrane part being fastened to an inner moving coil and the outer membrane part being fastened to an outer moving coil.

Abstract: A magnetic circuit of the present invention uses a yoke, wherein a thickness of a bottom portion 10b of the yoke 10 is thicker than a thickness of an outer cylindrical portion 10a. The magnetic circuit of the present invention comprises the yoke, a magnet 2 bonded to the bottom portion of the yoke, and a top plate 3 bonded to the magnet, a magnetic gap being formed between the top plate and the outer cylindrical portion. According to a configuration of the present invention, it is possible to reduce the magnetic saturation in the bottom portion of the yoke and to improve the efficiency of the magnetic circuit. As a result, the configuration contributes to improve the performance and efficiency of a loudspeaker using the magnetic circuit of the present invention.

Abstract: A loudspeaker comprising at least one magnet 27, yoke 24 fixed to a bottom surface of the magnet, flat plate 26 fixed on an upper surface of the magnet, magnetic circuit 29 having magnetic gap 28 formed between the plate and the yoke, and flat diaphragm 23 provided with coil 21 disposed above the magnetic gap. The magnet has a width greater than that of the plate, and at least a part of the upper surface of magnet is exposed so that it faces directly to the diaphragm. According to the structure of the present invention, a larger volume magnet can be used without increasing a size of the magnetic circuit. Furthermore, as magnetic flux can be concentrated to an upper region of the magnetic gap, the magnetic circuit becomes efficient and compact. Thus a compact and high-efficiency loudspeaker for high frequency sounds reproduction can be provided.

Abstract: An electroacoustic transducer comprising a magnetic circuit of a magnetically conductive material with a pair of opposed surfaces defining a gap there between, the magnetic circuit comprising one magnet. The magnet can either be positioned in the centre of the magnetically conductive material so as to form two gaps. In an alternative embodiment the magnet is attached to the magnetic conductive material forming only one gap. The transducer further comprises a diaphragm and a coil system having electrically conducting paths fastened to the diaphragm. The coil system has portions of its paths situated in the gap. The transducer may be supplied with an additional diaphragm and coil system positioned on the opposite side of the magnetic circuit. In a preferred embodiment the transducer is rectangular. The transducer is suited for integration into miniature components such as mobile communication equipment and hearing aids.

Abstract: A magnetic circuit for a speaker comprises: a bonded magnet shaped rectangular in top plan view, having on its top face a plurality of grooves formed to extend all the way along two opposing sides thereof and arrayed in parallel with one another at predetermined intervals, and magnetized such that magnetic fluxes at two adjacent grooves are directed inversely to each other; and a plurality of plate-like pole pieces fixedly disposed on the top face of the bonded magnet, and arrayed along the grooves such that two adjacent pole pieces form an air gap located along the center of each groove thereby forming a magnetic gap. And, there is provided a speaker which uses the magnetic circuit thereby achieving a reduced profile.

Abstract: An electromagnetic transducer such as an audio speaker, having a push-push geometry in which there are two or more air gaps and the magnetic flux across the air gaps is in the same orientation. If there are more than one voice coil, the voice coils may thus be generating the same electromagnetic polarity by being wound in the same direction about the bobbin, or by being wound in opposite directions and having separate, opposite polarity electrical connections. The transducer exhibits high linearity over a long travel.