Abstract: A loudspeaker including a frame, a movable diaphragm that oscillates, and a suspension for mounting the diaphragm to the frame, where the suspension comprises a flexible surround having a substantially enclosed space where at least a portion of the flexible surround is air permeable.

Abstract: A loudspeaker system, and a method and device for actuating a loudspeaker, using a loudspeaker element connected to a memory metal part and provided in a portable electronic device; and a power source unit configured to supply power to the memory metal part, wherein, when power is supplied to the memory metal part, the memory metal part is configured to exert a force on the loudspeaker element to actuate it.

Abstract: A loudspeaker suspension structure has an inner circumferential border, and an outer circumferential border, and grooves each extending from the inner circumferential border to the outer circumferential border at an angle with respect to a normal to the inner circumferential border, a profile of a circumferential section of the suspension structure having continuous curvature. Each of the grooves varies from the inner border to the outer border, the variation corresponding to a variation of a principal contour of the suspension structure.

Abstract: A speaker of the present invention includes the following: a diaphragm that includes an inner periphery coupled to a voice coil, and a corrugation provided at the intermediate position between the inner periphery and an outer periphery; a speaker edge for supporting the outer periphery of the diaphragm; and a damping member attached to an outer peripheral part of the diaphragm outside the vicinity of an outer periphery of the corrugation. The effective vibration area of an inner peripheral part of the diaphragm inside an inner periphery of the corrugation is substantially half or less of the total effective vibration area. The damping member is configured as a damping portion by extending an overlap portion of the speaker edge overlapping with the diaphragm to the vicinity of the outer periphery of the corrugation.

Abstract: An acoustic apparatus comprising a yoke, a main speaker mechanism disposed on a first surface of the yoke, and a sub speaker mechanism disposed on a second surface of the yoke opposite to the first surface and adjacent to the main speaker mechanism, the main speaker mechanism including a first magnet disposed on the first surface of the yoke, a first top plate disposed on the first magnet, a vibration-transmitting panel attached to the yoke and contactable with a vibrating member in a communication device, and a first voice coil attached to the vibration-transmitting panel and inserted in a first magnetic gap formed between the yoke and the first magnet, the sub speaker mechanism including a second magnet disposed on the second surface of the yoke, a second top plate disposed on the second magnet, a vibrating plate attached to a frame disposed to surround the yoke and a second voice coil attached to the vibrating plate and inserted in a second magnetic gap formed between the yoke and the second magnet.

Abstract: Various linkage assemblies are shown and described for connecting a first movable member to a second movable member of a transducer. The linkage assemblies provide for motion amplification or reduction and, when used for sound generating purposes such as hearing aids or speakers, three different schemes for compensating for amplification-induced distortion. One scheme for compensating for distortion while providing amplification is the use of a lower horizontal span segment in a closed-loop linkage assembly that is longer than a corresponding upper horizontal span segment or upper vertex. Thus, a horizontal span segment used to connect the loop to the first movable member of the armature is longer than a corresponding segment or vertex used to connect the loop to the second movable member. A second distortion compensating feature that provides amplification is found in the use of non-parallel legs used to connect the linkage loop to the housing.

Abstract: A speaker that is designed to substantially eliminate wobble of the voice coil during operation, and thus remove that source of distortion and early failure of the speaker. This is accomplished with the creation of triangular ring that extends upward from the top edge of the voice coil bobbin with that ring mating with a flat diaphragm at a right angle directly above the top edge of the bobbin. The outer edge of the diaphragm connects to the inner edge of the surround at the point where a sloping side of the “triangle” is also connected and slopes down to the top edge of the bobbin where the opposite end is connected. The outer portion of the diaphragm provides the third side of the triangle.

Abstract: The present invention provides methods and apparatuses for an audio transducer. The audio transducer is excited by driving a paddle of a diaphragm. A plurality of node regions of a paddle is determined for the higher-order modal components, which correspond to resonance frequencies and have an order greater than one. An intersection region of at least two higher-order modal components is identified, in which an excitation point is located with the intersection region. The diaphragm of the audio transducer includes a frame, at least one hinge, and a paddle. The paddle connects to the frame by the at least one hinge and is excited by a signal source at an excitation point to produce an acoustic signal.

Abstract: A diaphragm subassembly comprises a voice coil, a diaphragm, a frame, and a pair of terminal members. A magnetic circuit unit comprises a yoke, a magnet, and a base. The diaphragm subassembly and the magnetic circuit unit are accommodated in a bottomed cylindrical cover. In the manufacturing process, the cover is placed with the open end directed upward. The diaphragm subassembly, the yoke, the magnet, and the base are dropped into the cover in this order. The manufacturing process of a dynamic electroacoustic transducer is thereby simplified.

Abstract: A frame with a pot type yoke incorporated therein is held on a seating base, and an adhesive supplying means is disposed at a position located in close proximity to this seating base. A supply head of this adhesive supplying means has its supply port opposing an end face of an annular portion. The supply of the adhesive is effected while the seating base is rotated, and the adhesive is supplied starting with one groove, and is supplied continuously up to the other groove.

Abstract: A microphone sensing element and a method for making the same are disclosed. The sensing element has a diaphragm and an attached electrical lead-out arm preferably made of polysilicon that are separated by an air gap from an underlying backplate region created on a conductive silicon substrate. The backplate region has acoustic holes created by removing an oxide filling in a continuous trench that surrounds hole edges and by removing oxide to form the air gap. The diaphragm is softly constrained along its edge by an elastic element that connects to a surrounding rigid polysilicon layer. The elastic element is typically a polymer such as parylene having a Young's modulus substantially less than that of the diaphragm. First and second electrodes are connected to the diaphragm through the lead-out arm and to the substrate through polysilicon via fillings, respectively, and thereby establish a variable capacitor circuit for acoustic sensing.

Abstract: A speaker includes a diaphragm having a central aperture at which a bobbin with a voice coil wound therearound is mounted, and mounted at the outer periphery thereof on a frame with an edge therebetween, and a magnetic circuit section that has a magnetic gap in which the bobbin is placed, and that drives the diaphragm to vibrate in the frontward and rearward direction. The speaker can use a larger diaphragm by providing the frame with an edge-mounting portion on which the edge is mounted, and a portion formed in front of the edge-mounting portion.

Abstract: A frame is provided with an opening allowing insertion of a jig for setting an inner rim of a suspension holder to a proper position. The jig ensures positive alignment of the suspension holder when making connection to the frame. The jig also ensures reliable bonding of a diaphragm to the suspension holder with a bonding agent, since it steadily supports the suspension holder in position during the bonding process. The positioning of the bobbin and a voice coil is thus reliable when being assembled, thereby improving acoustic performance of a speaker.

Abstract: In a speaker device, a supporting member is arranged on a central axis, a diaphragm is provided on an outer circumference of the supporting member, and a damper is provided on the diaphragm. Preferably, the damper has a waterproof property. An inner peripheral edge portion of the damper is fixed to the supporting member on a sound output side with respect to the diaphragm, and an outer peripheral edge portion thereof is fixed to the diaphragm. The damper has a bent raised portion, on the outer peripheral side with respect to the fixing position to the diaphragm. By forming the bent portion on the outer peripheral end of the damper, it can be suppressed or prevented that the outer peripheral edge portion of the damper is deformed by a solvent of an adhesive agent at the time of attaching the outer peripheral edge portion of the damper and the diaphragm.

Abstract: A speaker device for improving mid/high-range frequencies includes a magnetic base, a frame annularly mounted to the magnetic base, a cone mounted to an inner side of the frame, a voice coil mounted to the cone and suspended in a gap of the magnetic base, and a deadening phase plug mounted on a central portion of the magnetic base. The magnetic base includes a T-iron, a magnet, and a pole plate. The deadening phase plug is made of a sound-absorbing material for absorbing and eliminating sound waves generated by the voice coil and the cone.

Abstract: A membrane (20) has a membrane axis (5) and a middle area (50), a central cup-shaped depression (52) being provided around said membrane axis (5), which depression (52) preferably has a connecting channel (53), wherein the middle area (50) comprises groups of stiffening grooves (54, 55, 56, 57) which extend parallel to radial directions and of which a first group of long stiffening grooves (54, 55, 56) extends up to the depression (52), said connecting channel (53) issuing into two of the long stiffening grooves (55, 56), thus interconnecting these two long stiffening grooves (55, 56).

Abstract: A loudspeaker has a diaphragm with an edge area and a central area. A voice coil carrier may be fastened to the diaphragm in the central area, a voice coil being wound around the voice coil carrier. A magnet system may be included into which the voice coil carrier and the voice coil are completely or partially inserted. A basket may enclose one face of the diaphragm and to which the magnet system is fastened. An elastic bead may be fastened to the edge area of the diaphragm and to the basket. A centering device may be fastened to the central area of the diaphragm and to the basket. The loudspeaker may include an additional elastic bead as a centering device, which is fastened directly or indirectly to the basket and the diaphragm.

Abstract: The invention relates to a loudspeaker comprising at least one magnet (5), a membrane (2) with an outer edge (32) defining an outer edge plane (30) of the membrane, a bead (3) surrounding the membrane (2), a moving coil (9) which is fixed to the first membrane (2), and a magnet system (4) comprising at least one magnet (9). The loudspeaker also has a supporting structure (1) for receiving the magnet system (4) and the membrane, the membrane being connected to the supporting structure by means of the bead, and the supporting structure has a front side which is oriented towards the membrane and a rear side which is oriented in the opposite direction. The membrane (2) is at least partially convex towards the front, in the predominant acoustic direction (33), and the region (28) of the membrane (2), to which the moving coil is fixed, is arranged in front of the outer edge plane (30) of the membrane.

Abstract: Electro-dynamic loudspeakers typically include a diaphragm having a conductor applied to one of its surfaces. The diaphragm is secured to a frame. The conductor is connected to a power supply for providing electrical current through linear traces of the conductor that interact with magnetic fields generated by magnets that are mounted to the frame. The diaphragm is driven by a motive force created when current passes through the conductor within the magnetic field. The electrical current is varied to create an acoustical output from the electro-dynamic loudspeaker. Different methods of tensioning the diaphragm are provided for simplifying the manufacturing process and for assuring proper diaphragm tension.

Abstract: There is provided methods for producing an ultrasonic transducer assembly. The methods generally comprise the steps of creating a multi-layered rigid or flexible printed circuit board, having a top surface and bottom surface; creating a patterned conducting layer upon each of the top and bottom surface; creating at least one patterned backplate electrode on the board or as part of a discreet component which is then attached to the board; creating at least one conductive through-hole via integral with the board; roughening at least a portion of each of the at least one backplate to introduce gas pockets in that portion of a surface of the backplate; and attaching thin insulating or dielectric single or multi-layer film on a portion of the board in which the film has an integral conducting surface and in which the conducting surface is configured so as to form a capacitive structure with the at least one backplate.

Abstract: The present invention is to provide a speaker to prevent deterioration of sound characteristics and to be easily inspected with eyes about a cause to deteriorate the sound characteristics. The speaker includes a magnetic circuit and a vibration portion. The magnetic circuit forms a magnetic gap and the vibration portion has a voice coil, a drive cone, and a diaphragm. The voice coil accepts signal current and is disposed in the magnetic gap. The drive cone is attached to the voice coil and has an upstanding segment at an outer edge of the drive cone. The diaphragm is superposed on the drive cone and the outer edge thereof is spaced from the upstanding segment. An adhesive agent is filled between the outer edge of the diaphragm and the upstanding segment to be fixed to the drive cone.

Abstract: A loudspeaker device 1 includes an acoustic diaphragm 5 composed of a domed diaphragm 11, an edge-like diaphragm 13, and a junctional flat portion 12 which joins those domed and edge-like diaphragms, and a joined portion 23 where an end surface of a bobbin 4 of a voice coil or of a conductive 1-turn ring 3 is stuck and fixed to the junctional flat portion 12 or a reinforcement ring 15; and the reinforcement ring 15 is stuck and fixed to the junctional flat portion 12 from above or from under, thereby increasing the mechanical strength of the junctional flat portion 12 of the acoustic diaphragm 5. A loudspeaker device in which unnecessary vibrations are removed and also the quality of acoustic signals is excellent up to high range is provided.

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: A speaker has a case having a peripheral projection, a magnetic device having a yoke, and a permanent magnet and secured to the case. A diaphragm is secured to the case at the peripheral projection. A protector has an upper plate and a cylindrical holding portion at the periphery of the upper plate. The protector is secured to the case at the cylindrical holding portion.

Abstract: A speaker is provided in which first and second voice coils are disposed around a voice coil bobbin, a diaphragm has its inner circumferences attached to an area of the voice coil bobbin positioned between the first and second voice coils and its outer circumference supported at the forefront portion of the frame via a surround, and a spider has its inner circumference attached to an area of the voice coil bobbin positioned between the first and second voice coils and its outer circumference supported at the middle portion of the frame. Since the outer circumferences of the diaphragm and the spider are attached to the voice coil bobbin at the area(s) between the first and second voice coils, the axial length of the voice coil bobbin can be reduced, and consequently the entire axial length of the speaker can bereduced.

Abstract: A speaker unit of the present invention includes a frame made of a synthetic resin, inside which a voice coil is disposed in a space between a pole piece and a yoke. A diaphragm is coupled to the voice coil. A pair of lead wires extending from the voice coil are passed between the yoke and the diaphragm, and led out of the frame. The frame has a receiving surface for receiving collisions of the lead wires due to vibrations of the diaphragm, which is formed outer than an end face of the yoke opposed to the diaphragm, and closer to the diaphragm than the end face.

Abstract: A loudspeaker apparatus includes a frame having an opening portion, a magnetic circuit constructed within the opening portion, a voice coil 27 in which a rear opening end portion is inserted into a magnetic gap of the magnetic circuit, a dome type diaphragm covered over the front opening end portion of the voice coil, and an edge for holding an outer peripheral portion of the voice coil freely vibratingly, with the outer peripheral edge attached on an opening portion of the frame. A reinforcing portion formed at an outer peripheral edge of the dome type diaphragm is formed of a flat portion and a cone portion, and has a shape of being folded back in a sound radiating direction toward a front.

Abstract: A method for fabricating a quartz nanoresonator which can be integrated on a substrate, along with other electronics is disclosed. In this method a quartz substrate is bonded to a base substrate. The quartz substrate is metallized so that a bias voltage is applied to the resonator, thereby causing the quartz substrate to resonate at resonant frequency greater than 100 MHz. The quartz substrate can then be used to drive other electrical elements with a frequency equal to its resonant frequency. The quartz substrate also contains tuning pads to adjust the resonant frequency of the resonator. Additionally, a method for accurately thinning a quartz substrate of the resonator is provided. The method allows the thickness of the quartz substrate to be monitored while the quartz substrate is simultaneously thinned.

Abstract: A loudspeaker includes a frame, a diaphragm and an electric driving arrangement for moving the diaphragm along an axis with respect to the frame. The diaphragm includes an outer conical first diaphragm body and an inner conical second diaphragm body invertedly oriented with respect to and positioned inside the first diaphragm body. The first and second diaphragm bodies each have a base portion and a top portion, the top portion of the first diaphragm body and the base portion of the second diaphragm body being interconnected. The diaphragm is suspended from the frame by a first flexible suspension member extending between the base portion of the first diaphragm body and the frame, and a second flexible suspension member extending between the top portion of the first diaphragm body and the frame. The top portion of the second diaphragm body is attached to a movable part of the driving arrangement.

Abstract: A speaker that is designed to substantially eliminate wobble of the voice coil during operation, and thus remove that source of distortion and early failure of the speaker. This is accomplished with the creation of triangular ring that extends upward from the top edge of the voice coil bobbin with that ring mating with a flat diaphragm at a right angle directly above the top edge of the bobbin. The outer edge of the diaphragm connects to the inner edge of the surround at the point where a sloping side of the “triangle” is also connected and slopes down to the top edge of the bobbin where the opposite end is connected. The outer portion of the diaphragm provides the third side of the triangle.

Abstract: A high efficiency loudspeaker without a damper is provided. The loudspeaker includes magnetic circuit having a magnetic gap and a voice coil member, which has movable coil, disposed in the magnetic gap of the magnetic circuit. The loudspeaker also includes a diaphragm, whose inner peripheral part is linked with the voice coil member, outside the magnetic gap and a frame linked with an outer peripheral part of the diaphragm via a first edge. An inner peripheral part of a suspension holder is linked with the voice coil member at a linked position which is closer to the magnetic circuit than a linked position of the diaphragm and the voice coil member. An outer peripheral part of the suspension holder is linked with a frame via a second edge. The first edge and the second edge are substantially symmetrical with each other about a median of a first edge and a second edge.

Abstract: The present invention relates to a semiconductor electret condenser microphone capable of being reduced in size and including an acoustic sensor 100 and a case 200 for accommodating the acoustic sensor 100, the acoustic sensor 100 has a semiconductor chip 110 forming necessary electronic circuits 111A to 111C, and opening a through hole 112 away from the electronic circuits 111A to 111C, an electrode layer 120 formed on the surface of the semiconductor chip 110 away from the through hole 112, an electret member 130 laminated away from part of the electrode layer 120 and through hole 112, and a diaphragm 140 provided with a spacing 160 to the electret member 130, in which the electrode layer 120 exposed from the electret member 130 is connected to the electrode 111a of the electronic circuit 111A through the case 200 (FIG. 6).

Abstract: A spider with an enhanced structure is disclosed. The spider has a plurality of concentric corrugations each of which has a plurality of inflections so that the concentric corrugations have polygonal shapes. With this enhanced structure, a spider can have an improved strength while maintaining an appropriate flexibility. A spider with the enhanced structure can avoid deformations due to un-uniform applications of external forces over a long period of time.

Abstract: A transducer for a hearing aid includes a housing, a relatively thin membrane having a free end suspended in the housing for vibration in response to a motor. The motor has a coil and a magnet assembly, the coil being mounted in the housing beneath the membrane; the magnet assembly being mounted in the housing coaxially with the coil and to one edge of the membrane.

Abstract: A speaker that is designed to substantially eliminate wobble of the voice coil during operation, and thus remove that source of distortion and early failure of the speaker. This is accomplished with the creation of triangular ring that extends upward from the top edge of the voice coil bobbin with that ring mating with a flat diaphragm at a right angle directly above the top edge of the bobbin. The outer edge of the diaphragm connects to the inner edge of the surround at the point where a sloping side of the “triangle” is also connected and slopes down to the top edge of the bobbin where the opposite end is connected. The outer portion of the diaphragm provides the third side of the triangle.

Abstract: A thin speaker having a magnetic circuit (2) disposed at the front of a cone-like diaphragm, wherein an internal magnetic type magnetic circuit (2) and a vibration system are supported by a sufficiently strong frame formed of two pieces having an outline of generally disk-shape and partly overlapped concentrically with each other, the acoustic characteristics are prevented from being deteriorated by preventing support bodies (7, 7A) for the magnetic circuit (2) from covering the forward of the sound emitting face of the cone-like diaphragm (3), and speaker component parts are formed so as to be assembled by stacking on one jig (1) from one direction with a specified procedure, whereby an assemblability can be improved.

Abstract: A case for containing an electrical instrument, comprises a frame having a peripheral wall portion, a cover member having a peripheral wall portion fitted on the peripheral wall portion of said frame and configured to form a space for containing the electrical instrument between the frame and the cover member, at least one hole provided in one of the peripheral wall portions of the frame and the cover member to fix the frame and the cover member, and a protrusion provided on the other of the peripheral wall portions of the frame and the cover member for being inserted in said hole.

Abstract: A method of manufacturing a thin quartz crystal wafer from a quartz crystal block which is cut from a crystal body of synthetic quartz crystal and has a flat principal surface, comprises the steps of (a) converging a laser beam at a region in said quartz crystal block at a predetermined depth from the principal surface thereof to cause multiphoton phenomenon state, thereby breaking Si—O—Si bonds of quartz crystal in said region to form voids in said region, and (b) peeling said thin quartz crystal wafer from a body of said quartz crystal block along said voids. The above process is repeatedly performed on one quartz crystal block to peel off a plurality of thin quartz crystal wafers successively from the principal surface of the quartz crystal block. Each of the thin quartz crystal wafers is divided into individual quartz crystal blanks for making quartz crystal units.

Abstract: An edge-driven diaphragm loudspeaker driver is configured such that the suspension system of the driver is connected to the voice coil rather than to the diaphragm. Thus, the diaphragm in the loudspeaker is free of suspension systems connected to or extending from the diaphragm. By attaching the surround suspension to the voice coil rather than to the diaphragm, the diaphragm is isolated from the influence of spurious high frequency vibrations in the suspension system, thereby increasing the performance of the loudspeaker at high frequencies. The loudspeaker driver configuration also provides for a longer excursion range for the voice coil/diaphragm assembly, which allows for the driver components to be more accurately aligned during manufacturing, thereby enabling the loudspeaker driver to operate as a full range unit by producing low output frequencies.

Abstract: An electroacoustic transducer has an annular permanent magnet provided in a frame, and an annular top plate mounted on the permanent magnet. A ring is secured to the upper surface of the top plate. A diaphragm is secured to the ring.

Abstract: Electro-dynamic loudspeakers typically include a diaphragm having a conductor applied to one of its surfaces. The diaphragm is secured to a frame. The conductor is connected to a power supply for providing electrical current through linear traces of the conductor that interact with magnetic fields generated by magnets that are mounted to the frame. The diaphragm is driven by a motive force created when current passes through the conductor within the magnetic field. The electrical current is varied to create an acoustical output from the electro-dynamic loudspeaker. Different frame structures are provided for simplifying the manufacturing process and defining a reduced cost electro-dynamic loudspeaker.

Abstract: An electroacoustic transducer employing a polymer connection for maximizing volume displacement. The transducer includes a diaphragm in a case and means for converting. The diaphragm includes a central portion. The means for converting converts between an electric signal and a vibration of the central portion of the diaphragm or vice versa while the diaphragm is coupled to the case. The central diaphragm has an outer edge, and between the outer edge and the inner wall of the transducer case a capillary space is present in which a polymer is provided as a coupling between the outer edge and the inner wall of the case.

Abstract: A method is provided for making a backing layer for an ultrasonic matrix array transducer useful in medical imaging and the like. A conductive grid is provided which includes a plurality of micro-contacts each joined together by a common base so that spaces are provided between the free ends of the contacts. A mold for the grid is filled with an acoustically absorbent material such that the absorbent material fills the spaces between the contacts, so as to produce a block when cured. The common base is removed so as to separate the contacts from one another within the block. Further machining exposes the opposite ends of micro-contacts so that a like number of contact faces or pads are provided at opposed surfaces of the backing layer. Improved transducer constructions are also disclosed.

Abstract: A loudspeaker module in the form of a ribbon element, where the module can be equipped with a membrane, 50 millimeters in width or narrower, and with any length from 50 millimeters to 2500 millimeters. The magnet system is equipped with so called booster-magnets in order to reduce loss of magnetic flow in the soft iron pole pieces and in order to equalize and in order to even the magnetic flow at the magnet ends. The signal-feed is designed in the form of passive current-feeding, whereby the inductance's negative impact of the frequency response up to the 1/f point is eliminated. Above the 1/f point, the ribbon membrane is compensation fed from a separate circuit consisting of R and C, whose values have been chosen in such a way that the resulting frequency response is flat over the whole operating area.

Abstract: The invention provides a continuous layer of polymer that is shaped to act as the suspension, the former, and an attachment to the diaphragm. The coil may be located within the pocket providing insulation to the coil thus preventing electrical short circuiting of the voice coil as the voice coil expands or contracts based on its operating temperature. The invention also provides an inner flange area of a suspension that may act as a spring generating additional acoustic energy from the compression driver. The inner flange area may also be tuned to vibrate at a predetermined high frequency. Thus, in certain applications, where more acoustic energy is desired at high frequency, the inner flange area may be tuned to provide that extra acoustic energy. To further increase the high frequency energy generated by the compression driver, the diaphragm may be coupled to the bottom side of the inner flange area.

Abstract: An acoustic transducer design having a slotted oval-shaped shell and active transducer elements located on the inner surface of the shell is disclosed. The design provides a high power, ultra-low frequency oval projector having a number of applications, including underwater seismic prospecting and fish mitigation.

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: The present invention relates to a semiconductor electret condenser microphone capable of being reduced in size and including an acoustic sensor 100 and a case 200 for accommodating the acoustic sensor 100, the acoustic sensor 100 has a semiconductor chip 110 forming necessary electronic circuits 111A to 111C, and opening a through hole 112 away from the electronic circuits 111A to 111C, an electrode layer 120 formed on the surface of the semiconductor chip 110 away from the through hole 112, an electret member 130 laminated away from part of the electrode layer 120 and through hole 112, and a diaphragm 140 provided with a spacing 160 to the electret member 130, in which the electrode layer 120 exposed from the electret member 130 is connected to the electrode 111a of the electronic circuit 111A through the case 200 (FIG. 6).

Abstract: An electromagnetic sound producing device has a yoke, a coil, a permanent magnet, and a diaphragm provided in a case. The permanent magnet is made of SmFeN-base isotropy plastic magnetic material.

Abstract: The surrounding structure of the loudspeaker forms an annular structure, including attaching parts and curved part. The cross section of the curved part is in a hollow and approximately elliptical form. The height along the major axis of the ellipse is made parallel to the center axis of the vibrating diaphragm of the loudspeaker while the width along the major axis of the ellipse is set in the direction orthogonal to the center axis of the vibrating diaphragm. In the elliptical surrounding structure having such a structure, the width in the cross section of the surrounding structure of the loudspeaker can be made narrow in comparison with a semi-circular surround, whereby the linearity of the amplitude and the maximum displacement are increased.