Abstract: A speaker edge includes a resin layer including a resin member and a fiber layer including a tangled fiber body. A melting temperature of the tangled fiber body is higher than a melting temperature of the resin member. The hardness of the tangled fiber body is lower than the hardness of the resin member.

Abstract: A loudspeaker resin molding component includes resin and bamboo fibers refined to have a microfibril status and carbonized. By this configuration, such a loudspeaker resin molding component can achieve both of a high elastic modulus and a large internal loss.

Abstract: A portable electronic device includes a housing. An opening is formed on the housing and a containing space is formed inside the housing. The portable electronic device further includes a speaker installed inside the containing space in a rotatable manner, a first magnetic component installed on a side of the speaker, a second magnetic component installed inside the housing and disposed on a side of the containing space for attracting the first magnetic component so as to position the first magnetic component on a first location, and a restoring component connected to the speaker for driving the speaker to rotate to a second location so as to expose the speaker outside the opening on the housing when magnetic attractive force between the first magnetic component and the second magnetic component disappears.

Abstract: A speaker device has a magnet, outer yokes, and inner yokes which are assembled so that a magnetic gap is formed between the outer yoke and inner yokes over which a magnetic flux which is generated from the magnet cuts across. A voice coil unit which is linked to a diaphragm is disposed within the magnetic gap, and positioning members determine the positions of the inner yokes and the outer yokes which attach magnetically to the magnet such that a magnetic gap is formed. The speaker device has a magnetic circuit of which the construction facilitates assembly, and recycling of various individual parts is relatively easy.

Abstract: A low frequency transducer arrangement includes at least one substantially annular magnet. A voice coil is disposed within and concentric with the magnet. A pole is disposed within and concentric with the voice coil. An air gap is defined between the magnet and the pole. The pole includes a bottom half having a downwardly facing axial recess. A plurality of first air passages extend laterally from the axial recess and fluidly interconnect the recess and the air gap. A top half has an upwardly facing axial recess. A plurality of second air passages extend laterally from the upwardly facing axial recess and fluidly interconnect the upwardly facing recess and the air gap. The first air passages and/or the second air passages are non-radially oriented.

Abstract: A connector housing made of resin includes a hole through which an eyelet terminal is inserted, a first wall for regulating a position of the eyelet terminal in an inserting direction of the eyelet terminal, and a second wall for regulating the position of the eyelet terminal in a direction opposite to the inserting direction of the eyelet terminal. The eyelet terminal includes a stopper contacts a wall surface and is provided at a place corresponding to the wall surface for regulating the position of the eyelet terminal in the inserting direction of the eyelet terminal, and a protrusion engaged with the second wall. The second wall is provided on a side wall surface of the hole. The above structure prevents the eyelet terminal from being taken off from the connector housing.

Abstract: A micro-speaker includes a yoke, a magnet assembly attached to the yoke, a voice coil, and a diaphragm connected with the voice coil. The yoke defines a bottom wall, and a number of sidewalls extending upwards from the bottom wall. The magnet assembly includes a main magnet positioned on the bottom wall, and a number of secondary magnets positioned on tops of the sidewalls.

Abstract: A balanced armature receiver includes a magnet, a coil, and a housing. The magnet and the coil are disposed within the housing and the housing comprising a bottom surface. The bottom surface includes a first bottom portion with a first dimension and a second bottom portion with a second dimension. The bottom surface further includes a stepped portion that is integrally formed with and connects the first bottom portion and the second bottom portion. The first dimension is greater than the second dimension. A second base of the second bottom portion is coupled to the magnet. The second base is adjacent to a first base formed in the first bottom portion allowing the coil to extend through a plane where the magnet and the second base meet.

Abstract: A loudspeaker includes a movable diaphragm, a resilient centering device for centering and guiding the movement of the diaphragm, and a magnet system for controlling the movement of the diaphragm, where the diaphragm is positioned between the magnet system and the resilient centering device.

Abstract: A micro-speaker includes a case having a cavity and a receiving hole, a magnetic circuit unit and a vibrating unit with a voice coil received in the cavity, a pair of needle seats embedded in the case for electrically connecting with the voice coil, a pair of pogo-pins arranged in the receiving hole for electrically connecting with the pair of needle seats. Each of the pogo-pins has a barrel unit, a first protrusion and a second protrusion extending from an outer surface of the barrel unit, at least one plunger extending from the barrel unit and projecting out of the receiving hole, a receiving space formed between the first protrusion and the second protrusion. A third protrusion extends from an inner surface of the receiving hole and accommodated in the receiving space for fixing the pogo-pin in the corresponding receiving hole.

Abstract: Disclosed is a micro-speaker. The micro-speaker includes a frame, a magnetic circuit unit assembled with the frame, a diaphragm extending along a longitudinal direction, a coil, an elastic member and an FPC. The diaphragm includes a top plate and a periphery portion surrounding the top plate. The top plate includes a supporting portion extending from the top plate towards the base wall of the frame and disposed at a periphery portion of the top plate in the longitudinal direction. The elastic member includes an elastic part, a first end connecting to the supporting portion of the diaphragm and a second end connecting to the frame.

Abstract: A transducer magnet for a low profile loudspeaker transducer is provided having a voice coil, surround suspension, diaphragm, and top plate. The transducer magnet may include a first magnet assembly, including an annular outer magnet having an outer perimeter, an outer diameter and an inner diameter. The inner diameter defines a vacant circular center within the annular outer magnet, and the difference in length between the diameter of the circular inner magnet and the inner diameter of annular outer magnet define an annular first magnet assembly air gap. The annular outer magnet includes one or more channels extending inwardly from the outer perimeter of the annular outer magnet to the first magnet assembly air gap, which is configured to receive the voice coil. The channels are configured to pass hookup wires from the voice coil to an external device from the transducer magnet.

Abstract: A speaker device includes a voice coil unit and a diaphragm linked to the voice coil unit. A first supporting unit and a second supporting unit elastically support the end portions of the voice coil unit so that the voice coil portion of the voice coil unit can vibrate within the magnetic gap in the direction of the face thereof. Each of the first supporting unit and the second supporting unit has a configuration that is in a shape bent so as to extend up and bend down from an end that is fixed to a fixing position. Thus, a speaker device in which the voice coil unit can vibrate with a greater amplitude is provided.

Abstract: A loudspeaker includes a diaphragm that vibrates back and forth to emit a sound, a magnetic circuit that is provided on a rear side of the diaphragm and has a magnetic gap on a diaphragm side, and a voice coil that is directly or indirectly joined to the diaphragm and disposed within the magnetic gap. A magnetic fluid is loaded within the magnetic gap. Also, a plurality of first edge pieces are provided at different positions in an outer circumferential portion of the diaphragm for vibratably supporting the diaphragm, each of the first edge pieces having a non-linear cross-sectional shape.

Abstract: An acoustic molded article, such as a frame for a speaker, used for an acoustic instrument, includes a regenerated glass and a regenerated resin both collected from household electric appliances which have been incinerated as fuel, or used for reclamation to be discarded. Thus, this article is an environment-friendly acoustic molded article which is light, high in rigidity and internal loss, and also capable of decreasing the discharge of carbon dioxide.

Abstract: The present invention relates to magnetic field interface clothes performing contactless magnetic field communication with a mobile terminal, the magnetic field interface clothes includes: a receiving part in which a mobile terminal is received and a coil part performing contactless magnetic field communication with a coil part of the mobile terminal at a position facing a coil part of the mobile terminal is formed, wherein the coil part formed in the receiving part includes a first coil and a second coil, the first coil and the second coil are received in the receiving part to have different winding directions.

Abstract: A speaker device, wherein vibration of a magnetic circuit section is suppressed with a magnetic influence on the magnetic circuit section suppressed. A speaker device having a vibration section and generating an audio sound by vibration of the vibration section is provided with a magnetic circuit section for forming a magnetic field for vibrating the vibration section and also with a weight section fixed to the magnetic circuit section and suppressing vibration of the magnetic circuit section subjected to reaction force caused by vibration of the vibration section. The weight section is fixed to the magnetic circuit section through a joint section for joining the magnetic circuit section and the weight section to each other, and this forms between the magnetic circuit section and the weight section a predetermined space for magnetically separating the magnetic circuit section and the weight section from each other.

Abstract: A loudspeaker includes a diaphragm that vibrates back and forth to emit a sound, a magnetic circuit that is provided on a rear side of the diaphragm and has a magnetic gap on a diaphragm side, and a voice coil that is directly or indirectly joined to the diaphragm and disposed within the magnetic gap. A magnetic fluid is loaded within the magnetic gap. Also, a plurality of first edge pieces are provided at different positions in an outer circumferential portion of the diaphragm for vibratably supporting the diaphragm, each of the first edge pieces having a non-linear cross-sectional shape.

Abstract: An inertial vibration exciter having a magnet assembly defining an annular gap, a coil assembly disposed in the annular gap, suspension means mounting the coil assembly for reciprocating movement in the gap, means coupling the coil assembly to a member to be vibrated, and a hermetically sealed housing in which the magnet assembly, the coil assembly, the suspension means and the coupling means are disposed. The housing may comprise a heat sink thermally coupled to the magnet assembly and the heat sink may be resiliently coupled to the housing. The coupling means may comprise a plate-like member to which the coil is rigidly attached and of a size substantially greater than the diameter of the coil. The plate-like member may be resiliently coupled to the housing.

Abstract: An electrodynamic speaker in which the number of steps of forming a tinsel wire to be connected to a voice coil and connecting the tinsel wire to a terminal can be reduced is provided. A frame of the electrodynamic speaker includes an edge mounting section, a magnetic circuit mounting section, a coupling section for coupling the edge mounting section and the magnetic circuit mounting section so as to define a plurality of window sections, a terminal fixing section for fixing a terminal, and at least one void for dividing the edge mounting section having an approximately annular shape, the void being communicatively connected to the window sections of the coupling section. A middle portion of the tinsel wire passes through the void or the window sections communicatively connected to the void, and the other end of the tinsel wire is connected and fixed to the terminal.

Abstract: An inductive electroacoustic transducer which includes a yoke, a magnetic circuit system disposing in the yoke, a vibration membrane which is driven by the magnetic circuit system, a cover coupled on one side of the yoke and it has a plurality of sound holes, and a circuit board which has a positive pole and a negative pole for importing acoustic electrical signals. The circuit board also has an inductive soldering disc and it is coupled to another side of the yoke. A portion of the yoke is connected to the inductive soldering disc with which it is conducted.

Abstract: An electroacoustical apparatus and method is described that alters the output properties of an audio device to improve the sound properties for both hearing impaired and normal hearing listeners. The device includes a coil element of specific design and may incorporate digital signal processing techniques to modify audio signal output. The electrical device and method of processing provides for the beneficial alteration of sound waves to an audio signal, and further modification of the audio signal to provide for improved loudness and clarity characteristics. The improved characteristics provide for greater intelligibility of the audio signal to persons with hearing impairments and to persons with normal hearing.

Abstract: Described is a vented speaker driver assembly utilizing a speaker driver having a pole piece that defines therein a vent that is not covered by a dust cap. The frame of the speaker driver is configured to be mounted to a structure's surface such that the pole piece of the driver is located within the structure's interior space. The vented speaker driver is configured to be utilized in a back-to-back vented driver assembly wherein the sound of more than one speaker driver is achieved in a footprint of only one driver and with minimized generation of physical vibrations from the assembly.

Abstract: A novel ribbon microphone incorporates rounded-edge magnet motor assembly, a backwave chamber, and a phantom-powered JFET circuit. In one embodiment of the invention, one or more novel rounded-edge magnets may be placed close to a ribbon of the ribbon microphone, wherein the one or more novel rounded-edge magnets reduce or minimize reflected sound wave interferences with the vibration of the ribbon during an operation of the ribbon microphone. Furthermore, in one embodiment of the invention, a novel backwave chamber operatively connected to a backside of the ribbon can minimize acoustic pressure, anomalies in frequency responses, and undesirable phase cancellation and doubling effects. Moreover, in one embodiment of the invention, a novel phantom-powered JFET preamplifier gain circuit can minimize undesirable sound distortions and reduce the cost of producing a conventional preamplifier gain circuit.

Abstract: An acoustic transducer includes a sound-producing member at least partially disposed within the first magnetic flux gap region between the magnetic poles, the sound-producing assemblage is magnetically excited through a magnetic circuit that passes from a location outside the magnetic flux gap region to inside the magnetic flux region through an air gap.

Abstract: The present disclosure relates to a coil transducer motor structure (20) including at least one coil (22), at least one magnetic element (23) arranged in use to provide a path for magnetic flux between the ends of said coil (22), wherein the magnetic element (23) has a structure providing a curvilinear path therethrough for said magnetic flux.

Abstract: A sensory signal output apparatus is provided. The sensory signal output apparatus, includes: a magnetic circuit vibrating in response to an alternating signal flowing through a coil; and an elastic support means elastically supporting the magnetic circuit to surround the circumferential outer surface of the magnetic circuit from one side direction thereof, in which coupling recesses are formed at the circumferential outer surface of the magnetic circuit to be spaced apart from each other, and a coupling piece is provided at a periphery of the elastic support means to be coupled to the coupling recess, the coupling piece is attached to and inserted into the coupling recess. In the sensory signal output apparatus, an elastic support means is inserted into and coupled to a magnetic circuit without using a curling operation to provide easy coupling.

Abstract: The inertial transducer comprises a foot, a modular key, at least one suspension means having at least three contact points, and heat dissipation means comprising multiple heat transfer points. The foot alternatively includes an opening or a cap. The cap may be frangible. Preferably, the foot includes a cylindrical wall that extends within the inertial transducer and the foot's lower surface is coplaner with the lower surface of a housing of the transducer, thereby reducing stack height. The cylindrical wall may or may not be threaded and may accept a shaft from a receiving apparatus used to associate the transducer with a substrate.

Abstract: An inductive electroacoustic transducer which includes a yoke, a magnetic circuit system disposing in the yoke, a vibration membrane which is driven by the magnetic circuit system, a cover coupled on one side of the yoke and it has a plurality of sound holes, and a circuit board which has a positive pole and a negative pole for importing acoustic electrical signals. The circuit board also has an inductive soldering disc and it is coupled to another side of the yoke. A portion of the yoke is connected to the inductive soldering disc with which it is conducted.

Abstract: A loudspeaker having a magnet system and a method of assembling the magnet system are disclosed. The magnet system comprises a magnet and an armature core that is mounted on the magnet. The magnet system also includes a shell pot configured to receive the magnet and the armature core in a hollow interior. The magnet system further includes a shaft that interlocks with the magnet, the armature core and the shell pot, and that is, on one end, mechanically connected to the shell pot. The magnet system also includes a push-on fastener that has an aperture through which the shaft passes and that is secured to the shaft at another end of the shaft such that it applies pressure onto the first surface of the armature core to fixedly position the armature core and the magnet with respect to the shell pot.

Abstract: Coaxial two-way or more loudspeaker system comprising a low range electro-dynamic transducer and a high range transducer with compression chamber, mounted in a coaxial and frontal with respect of the low range transducer.

Abstract: An example apparatus comprises a drive coil energizable by a drive signal, at least one permanent magnet, and at least one magnetic return path element for flux induced by the drive signal, the magnetic return path element, such as a balanced armature, being configured to provide a variable reluctance, so as to reduce nonlinearities in a displacement versus drive signal relationship. Modifying the reluctance versus flux properties of the magnetic return path of a transducer, e.g. the armature of a balanced armature device, allows compensation for nonlinearity arising in another part of the apparatus.

Abstract: The present invention provides a sensory signal output apparatus wherein a coil is disposed in the gap between a magnet/top plate and a yoke, and a portion elastically supported in the free space vibrates in reaction to the magnetic flux generated in the gap in accordance with the direction of the alternating current signal applied to the coil to generate sound and/or vibration, wherein the yoke has a groove formed at a side other than that with the magnet, and the groove has a diameter smaller than that of the magnet, and an inner edge portion with a magnetic fluid. The sensory signal output apparatus of the present invention improves the position retaining force of the magnetic fluid and reduces the deformation of the magnetic fluid, as the magnetic fluid is formed in the edge of the groove of the yoke corresponding to the edge portion of the magnet which has a relatively bigger magnetic force and magnetic field than the plane portion of the magnet.

Abstract: In configuring a magnetic circuit, by forming polarities of a magnet to be aligned along a vertical direction, and by optimizing a yoke providing a flow path of a magnetic flux, a vibration system is formed inside a magnetic circuit, so that a height of a speaker can be remarkably reduced. Additionally, by increasing a volume of the magnet and a diameter of a bobbin, a speaker with enhanced sound effect characteristics may be provided herein.

Abstract: A speaker includes a diaphragm 11, edges 12, at least one voice coil bobbin 14, a voice coil 15, and a magnetic circuit 21. The diaphragm 11 is a long flat plate. The edges 12 at ends of the diaphragm 11 in a longer-side direction support the diaphragm 11 to vibrate. The voice coil bobbin 14 has a substantially square pillar shape with a height more than twice as vibrational amplitude of the diaphragm 11, includes an opening having a periphery connected directly to the diaphragm 11, and supports the diaphragm 11 to transmit vibration to it. The voice coil 15 is wound around an outer periphery of the voice coil bobbin 14 substantially at center in a height direction. The magnetic circuit 12 drives the voice coil 15. The long speaker is unlikely to cause breakeup resonance, and has smooth frequency characteristics to offer good sound quality.

Abstract: A loudspeaker includes a frame coupled to a magnetic circuit, a cone diaphragm coupled to an outer periphery of the frame, a voice coil coupled to the cone diaphragm, the voice coil having a portion placed in a magnetic gap of the magnetic circuit, a tubular port having an end coupled to the voice coil, and a diameter of another end of the tubular port is larger than a diameter of a connecting portion at which the end of the tubular port is coupled to the voice coil, and a dome covering an upper end of the tubular port. A center axis of the tubular port inclines at least by 5° with respect to a center axis of the voice coil.

Abstract: A magnetic circuit includes a cylindrical yoke member having an inner circumferential surface and a collar formed at one end thereof and turned back substantially at right angles, and a plurality of permanent magnet segments of a partially circular arc in cross section. Each of the permanent magnets has an outer surface attracted magnetically to the inner circumferential surface of the cylindrical yoke member, and one end face attracted magnetically to the collar of the cylindrical yoke member. The magnetic circuit is applied to an actuator or a speaker.

Abstract: A speaker of the present invention is used for converting audio electrical signals to audible sounds. The multi-magnetic circuit speaker includes a box with a sound hole, at least one magnetic circuit having at least two magnetic gaps, at least two vibrating units corresponding to the magnetic gaps, respectively, at least two pair of pads embedded in the box to electrically connecting with the two vibrating units, a terminal board engaged with the box and pressing on the two pads for conducting electrical signals to the two vibrating units. The terminal board includes a first portion, a second portion extending from the second portion and a third portion extending from the second portion.

Abstract: A speaker is disclosed herein. And, in configuring a magnetic circuit of the speaker, unlike the vertical polarity alignment of the related art speaker, the polarities of the magnet are configured to be horizontally aligned, and a vibration system is configured on an inner side surface of the vertically configured magnetic circuit. Accordingly, by having the magnetic circuit encircle the vibration system, unlike in the related art speaker, wherein the height of the speaker corresponds to a sum of the thickness of the vibration system and the thickness of the magnetic circuit, the speaker may be configured only by using the height of the magnetic circuit. Furthermore, by being capable of reducing the height of the speaker, even if the volume of the magnet is being increased, the sound effect of the speaker may be enhanced.

Abstract: The present invention relates to a loudspeaker in the acoustic field and the information communication field. The invention provides a loudspeaker that can realize a thinner size. To achieve this, the loudspeaker of the present invention is structured so that a part of a diaphragm is inserted to a dent or an opening formed at the center poles of a lower plate of a magnetic circuit. This structure allows the diaphragm to be stored within the height of the magnetic circuit, thus allowing the loudspeaker to have a thinner size.

Abstract: A vibration device includes a support system member that supports a diaphragm to allow vibration, a tubular voice coil bobbin attached to the diaphragm, and a magnet disposed on at least one of inner and outer circumferential surface sides of the bobbin. The magnet is polarized in a vibration direction of the diaphragm, and forms a magnetic gap on a side that faces the bobbin. A voice coil is attached to the bobbin and disposed within the magnetic gap, and vibrates the diaphragm and the bobbin in response to a driving force generated when an electrical signal is inputted into the voice coil. A magnetic material member is attached to the bobbin, disposed in a balancing position within the magnetic gap, and, when vibrating with the bobbin, subjected to a magnetic attractive force in a direction away from the balancing position.

Abstract: A magnetic circuit includes an inner permanent magnet assembly and an outer permanent magnet assembly, a magnetically permeable yoke, and first and second air gap portions conducting first and second magnetic flux densities, respectively, the first and second air gap portions being adapted to receive first and second voice coil segments, respectively. The magnetic flux density in the first air gap portion is generated by superposition of magnetic flux generated by the inner permanent magnet assembly and magnetic flux generated by the outer permanent magnet assembly, and wherein the magnetic flux density in the second air gap portion is generated substantially exclusively by the inner permanent magnet assembly.

Abstract: A speaker includes an elongated diaphragm and a coupling member including forward and rearward segments, wherein at least two protrusions are provided at the rear side of the diaphragm along the major axis direction, the forward segment is engagingly disposed between the opposing end faces of two adjacent protrusions and also between the two portions of a rib of the diaphragm opposing each other in the minor axis direction, and wherein the outer circumferential surface of the voice coil bobbin is connected to the inner circumferential surface of the rearward segment, whereby the voice coil bobbin having a diameter larger than the dimension of the diaphragm measured along the minor axis direction can be successfully attached to the diaphragm. In the speaker described above, the diameter of the voice coil bobbin can be increased without decreasing the width of a surround thus enabling the withstanding of higher power input.

Abstract: A magnetic circuit and a speaker including the magnetic circuit. The speaker includes: a bottom case; a magnetic circuit including a perpendicular-magnetized permanent magnet and a horizontal-magnetized permanent magnet spaced apart from each other by a predetermined interval; a diaphragm; a voice coil attached on a surface of the diaphragm, disposed in a magnetic gap between the perpendicular-magnetized permanent magnet and the horizontal-magnetized permanent magnet and which vibrates the diaphragm; and a front cover coupled to the bottom case to fix the magnetic circuit and the diaphragm. The magnetic circuit includes a perpendicular-magnetized permanent magnet and a plurality of horizontal-magnetized permanent magnets.

Abstract: A magnet structure for use with a loudspeaker has an interlocking mechanism. The magnet structure can include a magnet, a shell pot and at least one core cap. The shell pot can contain the magnet in its hollow interior. The magnet can be a single magnet or double magnets. The core cap has two surfaces. For a single magnet, one surface of the core cap faces the magnet. For double magnets, the core cap can be vertically disposed between the two magnets. The magnet, the core cap and the shell pot can interlock with one another such that a position of the magnet relative to the core cap and the shell pot can be rigidly preserved. The magnet can be configured to be, for example, overlapped, inserted, staked and/or engaged with at least one of the shell pot or the core cap.

Abstract: Loudspeakers are provided that include a moveable magnet that can be positioned relative to the speaker piston. A user of the loudspeaker may position the moveable magnet to achieve a desired tone, distortion, or other sound without requiring the loudspeaker to be operated at an undesirable sound pressure level. The loudspeaker may include an indicator showing the relative position of the magnet relative to the piston to the user.

Abstract: A method of soldering terminals of a micro-speaker on a circuit board comprises the following steps. Firstly, providing a circuit board having a pair of through holes passing therethrough, and two soldering sections defined surrounding the pair of through holes. Secondly, the soldering sections are plated with soldering tin. Thirdly, providing a pair of columned terminals, the terminal includes an upper portion, a low portion and a body connecting between the upper portion and the low portion. Fourthly, the low portion of the terminal is inserted into the corresponding through hole and the body is resisted on the soldering section. Fifthly, the soldering tin is heated to solder the body on the soldering tin. Finally, the upper portion of the terminal is soldered onto the corresponding end of the voice coil. As a result, soldering defective can be reduced.

Abstract: A low profile miniature speaker configured for use in greeting cards such as sound generating greeting cards and other novelties. The thickness of the speaker is minimized while maintaining the sound quality and increasing strength. The speaker magnet is counter-sunk into the housing of the speaker, thereby decreasing overall thickness. The speaker is configured with concentric ribs that radiate outward from the center of the circular speaker. The ribs reinforce the plastic housing and increase the structural strength of the speaker.

Abstract: A diaphragm is formed of paper manufactured from a first fiber material and a second fiber material. The first fiber material is beaten to have a given freeness, and the second fiber material is made by carbonizing bamboo fiber that has been fibrillated into a microfibril state. This structure allows the second fiber material to increase a rigidity of the diaphragm and also increase an internal loss, so that sound quality of the speaker that employs this diaphragm can be improved.

Abstract: An electrodynamic transducer with a membrane includes an electrodynamic motor in a carcass in which a coil held by a mandrel connected to the membrane is capable of movement. The mandrel has a shape generated by an essentially linear generatrix, the coil being arranged in an air gap of a vertical free space where it is capable of movement and defined, towards the center of the transducer, by an inner magnetic structure and, towards the periphery of the transducer, by an outer magnetic structure, at least one of the magnetic structures generating a static magnetic field, wherein the transducer does not include any peripheral nor inner suspension and the guiding of the mobile equipment and the pneumatic tightness between the front and rear faces of the membrane being ensured by a ferrofluid. The mandrel is maintained in the air gap by the ferrofluid applied on at least one of the two faces of the mandrel and entirely filling the air gap.