Abstract: The invention is a novel circuit wherein maximum shove is achieved yet the transducer's height profile is minimized. The profile is minimized by using mated beveled surfaces on an annular magnet and the top plate which prevents the top plate from reaching saturation and reduces the reluctance f the magnetic flux path. A novel anti-fringe geometry to reduce flux leakage and net saturation in the center post improves the magnetic reluctance of the circuit. An external housing assembly is provided with integral suspension elements for radial stiffness and axial compliance and for aligning the circuit within the housing to prevent cocking and resulting distortion.

Abstract: A voice coil bobbin coupled to a damper is allowed to vibrate in its axis direction within a magnetic circuit including a magnet and a plate supported by a yoke. A range extending between a neutral position of an end of the voice coil bobbin and a portion of the yoke opposing the end of the voice coil bobbin is longer than a range extending between the plate and a neutral position of a portion where the voice coil bobbin is coupled to the damper. A damper ring is fitted around the voice coil bobbin in a position closer to the plate within the portion where the voice coil bobbin is coupled to the damper. A rear face of the damper ring opposing the plate is shaped in face-geometry parallel to a face of the plate opposing the damper ring.

Abstract: An electro-acoustic transducer includes a tone generator, a vibrator, and a case. The tone generator includes a diaphragm, and a voice coil joined to the diaphragm. The vibrator includes a magnetic circuit having a magnetic gap at which the voice coil is positioned, and a suspension made of metal and having a first end joined to the magnetic circuit to suspend the magnetic circuit for allowing the magnetic circuit to vibrate. The case is joined to a periphery of the diaphragm, and includes a metal plate joined to a second end of the suspension. The metal plate is joined to the suspensions reliably, hence allowing the electro-acoustic transducer to be manufactured stably.

Abstract: An electrodynamic exciter has a tubular frame, a magnetic circuit assembly, a voice coil, and first and second suspensions axially vibratably supporting the magnetic circuit assembly and the voice coil, respectively, in the frame. One end of the frame is secured to a diaphragm to form an air chamber between the second suspension and the diaphragm. The vibration of the voice coil is transmitted to the diaphragm from the second suspension through the frame and also from the second suspension through the air chamber. The air chamber functions as an air spring or an air damper. Thus, vibrations of the voice coil in the mid and high frequency audio range are efficiently transmitted to the diaphragm, and the sound pressure level of the diaphragm in the mid and high frequency audio range is increased.

Abstract: The invention relates to a moving-coil electrodynamic motor and a loudspeaker. A moving-coil includes a winding with a given number of turns. A motor comprises a magnet arranged between a front pole piece and a rear pole piece. The front pole piece and the rear pole piece enclose a magnetic field in a gap and the moving coil is arranged in the gap. The gap may include a groove arranged essentially parallel to the turns. The coil has a height less than or equal to the height of the gap and the groove forms a recessed zone with an internal ring made from electrically conducting material.

Abstract: An audio speaker having a removable voice coil, which may be a part of a voice coil assembly. The voice coil may be user-removable to facilitate replacement of a damaged voice coil or reconfiguration of a speaker system. Properly positioning the voice coil assembly may provide a solder-free electrical connection between the voice coil and leads that provide current to the voice coil. In some embodiments, the voice coil is user-removably attached to an inner circumferential surface of a diaphragm. In other embodiments, the voice coil is connected to the diaphragm, and the voice coil assembly and the diaphragm are both user-removably attached to a frame.

Abstract: An electromagnetic transducer is described including a magnet assembly (50) and a conductive drive coil (52). The magnet assembly provides an emanating magnetic field within which the drive coil is located. The drive coil is a flat ring coil having a width that is equal to or greater than its height. As assembled, the drive coil is mounted in close proximity to the magnet assembly such that relative axial motion may occur between them during use. In one embodiment, the magnet assembly includes two permanent disc magnets (64), (66) having axial magnetizations and being oriented with like poles facing one another to produce a radially emanating magnetic field. In another embodiment, the magnet assembly includes a pair of axially magnetized permanent ring magnets (64), (66) also oriented with like poles facing one another.

Abstract: A speaker cabinet including at least one bass speaker having a voice coil aligned by a magnetic fluid without a ‘spider’ and having an anodised metal cone, and at least one further speaker having a thin conductive membrane, and having integrated preamplifiers and at least one power amplifier, for use with musical instruments, for playing small to medium sized venues and/or for use as a personal monitor speaker on a performance stage for playing medium to large venues. Multiple channels are provided to amplify more than one instrument, and microphone inputs are provided for acoustic instruments and/or voice amplification. A line level input is also provided for external signal sources. An auxiliary input is provided to facilitate the monitoring of accompanying musicians, thus permitting the loudspeaker system to also function as a stage monitor. Reverberation and notch filtering, as well as tone control, may also be provided.

Abstract: A vibrator of the present invention comprises a coreless coil (2), a driver (4) including a magnet (4a) inserted in the coreless coil (2), a yoke (4b) for pinching the coreless coil (2) and facing the magnet (4a), and a top plate (4c), suspensions (6 and 8) for carrying resiliently the driver (4). The driver (4) is reciprocated in an axial direction of the coreless coil (2) by applying an alternate current to the coreless coil (2) to generate vibrations. The vibrator can be miniaturized without increasing a cost and has a good rising of vibrations.

Abstract: The present invention relates to a multi-function actuator, in which a voice coil vibrates a sound-generating diaphragm in response to an audio signal. A vibration coil is placed on a central axis coaxial with the voice coil for generating vibration in response to the audio signal or a vibration signal. A vibration unit includes a magnet for generating a magnetic field to both of the voice coil and the vibration coil and a yoke having a predetermined mass. The vibration unit is vertically vibrated by an electromagnetic force produced from at least one of the voice coil and the vibration coil. A switch selectively applies the audio signal to the vibration coil. The multi-function actuator can prevent the vibration of the vibration unit during sound generation in response to user's switch selection.

Abstract: Disclosed is a voice coil mounting structure, which includes a reel, which has a first end mounted with a coil and a second end provided with equiangularly spaced female retaining portions, and a reel holder, which defines an annular space for accommodating the second end of the reel and has female retaining portions provided inside the annular space for engagement with the female retaining portions to lock the reel to the reel holder upon a rotary motion of the reel relative to the reel holder after insertion of the second end of the reel into the annular space.

Abstract: An improved structure for the sound coil of loudspeaker comprises a cylinder provided with multiple layers of coils surrounding one end thereon. The coils are divided into sections in the middle position which provide more than two conducting wires. The cylinder is rolled by a single plate and is provided with four layers of coils. The conducting wire extends to the other end of cylinder and is wrapped with oilpaper; and connects to a piece of thick wire. The cylinder is provided with several ventilation holes. Every two layers of coil being a independent wire material, the sound coil comprised four conducting wires; or each layer of coil being a independent wire material, the sound coil comprised eight conducting wires. Thus the sound coil produces larger output power and reduces the size of sound coil, the coils surrounding the cylinder, production costs, and the size of products.

Abstract: In a loudspeaker, even if an interval between a diaphragm and a yoke is small, a lead wire, an end of the coil wire of a voice coil, moves upward and downward in and/or over a cutout portion formed in the yoke, and does not collide with the yoke. The loudspeaker does not have disadvantages, such as noises and disconnection of the end of the coil wire, and can be thin.

Abstract: A speaker is provided in which a coil wire can withstand a large amplitude motion caused by vibration of a voice coil bobbin and a diaphragm, and in which a bias of weight of the voice coil bobbin and the diaphragm caused by a constitution of the coil wire is reduced to a minimum. The coil wire, winding around the voice coil bobbin, is composed of a core thread having a bending strength and a heat-resistance and is wound by a conductive material. An end of the coil wire is directly connected to an external input terminal attached to a frame.

Abstract: In an electromagnetic induction type speaker apparatus, individual constants are set in such a manner that the following formula is satisfied N×(R1×R2)1/2/(2?×L1×(1?k2)1/2>2000 where R1 is the DC resistance of a primary coil; L1 is the inductance of the primary coil; N is the number of turns of the primary coil; R2 is the DC resistance of the secondary coil; L2 is the inductance of the secondary coil; and k is the coupling coefficient of the primary coil and the secondary coil. In addition, the constants L1 and l2 are selected in such a manner that the ratio of the inductance L1 and the inductance L2 becomes equal to the ratio of the DC resistance R1 and the DC resistance R2.

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: A speaker has a relay portion disposed on a resin frame for relaying the connection between a terminal and a voice coil. The relay portion comprises a clamping section and a wall section, and is configured so that a flexible wire does not make contact with a diaphragm or a damper during operation of the speaker. The assembly operation for placing and fixing the flexible wire becomes quite easy, and the number of components can be reduced among the speakers in accordance with the present invention.

Abstract: In an electromagnetic induction type speaker apparatus, individual constants are set in such a manner that the following formula is satisfied N×(R1×R2)1/2/{2 ?×L1×(1?k2)1/2}?20000 where R1 is the DC resistance of a primary coil 15: L1 is the inductance of the primary coil 15; N is the number of turns of the primary coil 15; R2 is the DC resistance of the secondary coil 18; L2 is the inductance of the secondary coil 18; and k is the coupling coefficient of the primary coil 15 and the secondary coil 18. In addition, the constants L1 and L2 are selected in such a manner that the ratio of the inductance L1 and the inductance L2 becomes equal to in the ratio of the DC resistance R1 and the DC resistance R2.

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: A vibration actuator in which a magnetic circuit device (1,2,3) is elastically suspended to a vibration transmitter (12) by a suspension plate (5)in a predetermined direction, a primary elastic member (6a) is interposed between the suspension plate and the magnetic circuit device in the predetermined direction. A coil (10) is fixed to a vibrating member (9) and disposed in a magnetic gap of the magnetic circuit. It is preferable that the suspension plate has a leaf spring portion extending along a spiral curve between central and peripheral portions thereof.

Abstract: This invention provides a speaker apparatus that outputs sound having smooth frequency characteristics. To solve the inconvenience with the prior art, this invention is a speaker apparatus comprising a diaphragm and a cylindrical-shaped coil bobbin, and not comprising a center cap that covers the coil bobbin, and where the diaphragm is located such that it rests on the coil bobbin, and the coil bobbin and diaphragm are located such that sound from the coil bobbin and diaphragm is not reflected.

Abstract: A moving coil transducer which comprises a yoke, permanent magnet and pole piece which are assembled to form a magnet circuit leaving an air gap between two opposing surfaces of the yoke and pole piece for receiving the moving coil. The permanent magnet is positioned between other opposing surfaces of the yoke and pole piece, and its faces are not parallel. Thus the thickness of the magnet increases away from the air gap of the magnetic circuit. In an annular or toroidal design in which the pole piece, permanent magnet and yoke are all annular and define an annular air gap, the magnet may be of conical form, having a thickness which increases away from the air gap. The pole piece and yoke are correpondingly tapered at the portions which meet the permanent magnet. The use of the non-flat magnet allows more magnetic material to be included in the transducer without increasing the overall volume of the transducer.

Abstract: An audio speaker having a removable voice coil, which may be a part of a voice coil assembly. The voice coil may be user-removable to facilitate replacement of a damaged voice coil or reconfiguration of a speaker system. Properly positioning the voice coil assembly may provide a solder-free electrical connection between the voice coil and leads that provide current to the voice coil. In some embodiments, the voice coil is user-removably attached to an inner circumferential surface of a diaphragm. In other embodiments, the voice coil is connected to the diaphragm, and the voice coil assembly and the diaphragm are both user-removably attached to a frame.

Abstract: The present invention provides an electromagnetic drive motor assembly (EDMA) that has an inner flux return assembly formed from an upper pole piece and a lower pole piece oppositely disposed relative to each other along the center of the EDMA. An annularly positioned conductive ring (or flux stabilization ring) encircles the inner flux return assembly, concentrically in contact with the outside of the inner flux return assembly. Along the exterior side of the flux return pieces, is a magnet that is between a top plate and a bottom plate. Each plate contacts with the magnet to form a magnetically conductive system. A magnetic gap is formed in between the inner flux return assembly and the top and bottom plates. Disposed within the magnetic gap is a dual coil wound around a cylinder. The dual coil includes a first coil portion and a second coil portion. To minimize the modulation, the top and bottom plates may be saturated and plate tips may be provided near the magnetic gap.

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: A sound reproduction apparatus includes a left channel speaker apparatus for receiving a left-channel sound output signal of a sound source, a right channel speaker apparatus for receiving a right-channel sound output signal and a center speaker apparatus disposed at the center, or in the central front space between the speaker apparatuses for the left and the right channels. A speaker unit of the center speaker apparatus is provided with a left-channel voice coil for receiving the left-channel sound output signal and a right-channel voice coil for receiving the right-channel sound output signal; and these two voice coils are disposed co-axially. The center speaker apparatus is formed only of the above-described speaker unit, a front baffle and a cabinet. The amplifying unit that was indispensable in the conventional configuration has been totally eliminated.

Abstract: Disclosed is a linear voice coil actuator having a latching feature, the actuator having a coil assembly, a field assembly, a magnetic structure positioned in the coil assembly, and a stop which limits the position of the magnetic structure with respect to the field assembly when the coil is not energized. The coil assembly has a coil base and a coil located in a cavity in the coil base. The field assembly preferably has an axially magnetized cylindrical magnet, a soft pole piece, and a soft magnetic housing. Preferably the magnetic structure is a magnetic plate positioned coaxially with the axis of magnetization of the magnet and having a diameter or a thickness which is selected to set a latching force between the plate and the magnet when the coil is not energized.

Abstract: A speaker comprising; a substantially rectangular case having connection terminals at corners, a substantially rectangular voice coil, a diaphragm, and a substantially rectangular magnetic circuit. The speaker of the present invention is characterized in that a lead drawn out from a corner of the voice coil in proximity to one of the connection terminals extends to the vicinity of another corner on a shorter side of the voice coil, is bent, and then is connected to the connection terminal. The present invention can provide a speaker for use in portable equipment, such as a portable telephone, that can meet the requirements of space reduction without impairing characteristics, such as sound quality and sound pressure, and has excellent connection reliability of the terminal and reduced cost.

Abstract: An electromagnetic transducer such as an audio speaker employs a slotted yoke and two suspension components enabling very large excursion relative to the size of the diaphragm which results in improved low frequency output. A first suspension component includes an inner ring, flexible springs, and an outer body. The flexible springs extend through the slots of the yoke and couple the inner ring to the outer body. The inner ring, outer body, and flexible springs of the first suspension component may be of monolithic construction or they may be distinct components coupled together. The inner ring couples to the bobbin of the diaphragm assembly, and the outer body couples to the outer cylindrical surface of the yoke or to a mounting ring which is coupled to the outer cylindrical surface of the yoke. A second suspension component, such as a surround, couples the diaphragm assembly and to the mounting ring.

Abstract: A conductor wire comprises a core, a copper-clad layer clad around the core, and an insulating layer provided therearound as required. The core is formed of an alloy of aluminum, magnesium and silicon for flatting with a purity of aluminum greater than or equal to 90%. The copper-clad layer has a cladding rate of 25-40% in an a real ratio. Adoption of the conductor wire provides a voice coil and a loudspeaker device with the same voice coil having excellent waterproof and effective strength.

Abstract: A loudspeaker comprises a frame, a magnetic circuit unit, a vibration unit and a snap fastening device. The frame has a recess. The magnetic circuit unit is received in the recess of the frame. The magnetic circuit unit includes a yoke. The vibration unit is received in the recess of the frame. The snap fastening device connects the yoke, which is inserted into the recess of the frame, to the frame.

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: 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: 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: 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: 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: A composition for a loudspeakers voice coil wire material that reduces the thermal modulation of the motor force factor due to wire resistance changes with temperature.

Abstract: The present invention provides an electromagnetic drive motor assembly (EDMA) that has an inner flux return assembly formed from an upper pole piece and a lower pole piece oppositely disposed relative to each other along the center of the EDMA. An annularly positioned conductive ring (or flux stabilization ring) encircles the inner flux return assembly, concentrically in contact with the outside of the inner flux return assembly. Along the exterior side of the flux return pieces, is a magnet that is between a top plate and a bottom plate. Each plate contacts with the magnet to form a magnetically conductive system. A magnetic gap is formed in between the inner flux return assembly and the top and bottom plates. Disposed within the magnetic gap is a dual coil wound around a cylinder. The dual coil includes a first coil portion and a second coil portion. To minimize the modulation, the top and bottom plates may be saturated and plate tips may be provided near the magnetic gap.

Abstract: A combination voice coil and diaphragm device for use in a receiver is disclosed having a diaphragm injection-molded from plastics, and a voice coil formed integral with the diaphragm by means of thin film plating. The voice coil has electrodes integral with the diaphragm and extended to the periphery of the diaphragm for quick installation in the receiver.

Abstract: It is one object for the present invention to improve current-carrying capacity of a wire and input characteristics. A speaker is provided with a wire unit, which is formed by combining a plurality of unit electric wires and the unit electric wires are electrically parallel with each other to form one voice coil; an insulation member for insulating the unit electric wires each other; a bobbin for being wound by the electric wires; a vibration plate for being vibrated by the bobbin; a magnet for surrounding the bobbin; a yoke for being substantially connected to the magnet; a plate for being substantially connected to the magnet; and a damper for being connected to the bobbin.

Abstract: Disposed within a space formed between a base cover (2) and a top cover (1) attached to the base cover (2) is an electromagnetic sound generating part which has a diaphragm (9) attached to the base cover (29) and a drive part causing the diaphragm (9) to vibrate. The drive part includes a yoke (5) fitted in the base cover (2), a magnet (7) mounted on the yoke (5), a top plate (8) mounted on the magnet (7) and an exciting coil (6) disposed to oppose to side surfaces of the magnet (7) and top plate (8). Coil contact springs (10) are contained into housings (2a) provided on portions of the base cover inside than an outer peripheral edge of the diaphragm. The coil contact springs (10) act to connect the exciting coil (6) with an outside power source. The base cover (2) is provided with a pair of connecting pieces (11) or lead frames which are used to connect the exciting coil (6) and coil contact springs (10). The connecting pieces (11) are embedded in the base cover (2).

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: 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 voice coil bobbin comprises a cloth material woven from longitudinal and lateral fibers, and transmits driving force caused by a voice coil wound thereon to a diaphragm. The longitudinal or lateral fibers are obliquely oriented with respect to the direction of the driving force. Thus, rigidity and mechanical strength required for the voice coil bobbin are ensured with reduced weight and cost.

Abstract: A hi-fi tweeter mainly comprises a diaphragm, an inner supporting edge, a voice coil, and a phase sensitive rectifier. The diaphragm is integrated with a coil core portion, made of unitary material to avoid structurally connecting to different material, and the inner supporting edge mounting the diaphragm and the coil core portion to the phase sensitive rectifier. The voice coil is wound around the coil core portion and produces excellent ultrahigh sound wave in 1 KHz-100 KHz range.

Abstract: A linearly compliant, flexible, resilient and flat speaker damper connected between the frame and the cone of the speaker with electrically conductive paths applied to the damper to conduct the signal to be applied to the voice coil of the speaker. A method for linearly compliant audio speaker damping and a method for application of voice coil conductors on the damper.

Abstract: Fixing of a voice coil (16) to a diaphragm (12) is performed by caulk-fixing a coil supporting member (26) to the diaphragm (12) and by fit-supporting the voice coil (16) by the coil supporting member (26). Hereby, the voice coil 16 is physically fixed to the diaphragm (12) and its fixing strength is heightened. The caulk-fixing is performed by subjecting a caulking projection of the coil supporting member (26) to a plastic deformation thereby to provide a caulk-fixed portion (26b), whereby deformation injurious to the acoustic property does not occur in the diaphragm (12). Further, the fit-supporting is performed by interposing a flange portion (16a1) formed at an upper end portion (16a) of the voice coil (16) between an engaging portion (26a) of the coil supporting member (26) and a central flat portion (12b) of the diaphragm (12) and holding it by them from upper and lower sides.

Abstract: The invention relates to a speaker that can cool a voice coil efficiently. A bobbin that supports the voice coil is made from a material having good thermal transfer characteristics. Slits are formed in the bobbin to further promote heat emission from the voice coil.

Abstract: An electroacoustic transducer operating in accordance with the electrodynamic principle include a diaphragm which has in the region of the coil an annular protrusion which is integrally connected to the diaphragm, wherein the coil is attached, preferably glued, to the annular protrusion at a desired distance from the diaphragm. The attachment can be end face against end face. The diaphragm may in the area of the coil have an annular reinforcing corrugation which is attached to the coil in an appropriate manner, preferably by gluing.

Abstract: An open-type magnetic circuitry of loudspeaker includes a lower yoke having a central portion upward projected to form a bobbin, a magnet positioned on top of the bobbin, a voice coil wound around the bobbin and the magnet, and a diaphragm connected at a root portion to the voice coil. The magnetic circuitry of loudspeaker is characterized in that the lower yoke is provided at an upper side surrounding the bobbin with a plurality of radially equally spaced supporting posts, a top end of which being higher than at least a bottom side of the magnet, and that a ring-shaped upper yoke having a central hole is covered onto the top end of the supporting posts, such that heat produced by the voice coil during working could quickly dissipate via the spaces among the supporting posts. Since no heat would accumulate in the loudspeaker, the loudspeaker could always maintain good sound quality.