Abstract: A loudspeaker is provided, which has a configuration in which suspension holder extending in a cylindrical shape widening downward is provided on the rear surface of diaphragm so as to be integrated with diaphragm, and the periphery of suspension holder is coupled to frame via second edge. With such a configuration, adhesion work between the suspension holder and the diaphragm as well as heating and drying work of adhesive are not required, thus enabling the productivity to be considerably improved and production equipment and space to be reduced.

Abstract: A diaphragm for use in a speaker is manufactured using a plurality of thin wooden boards having flat rectangular shapes. The thin wooden boards are impregnated with a resin; then, a plurality of cutouts, which are elongated along wooden fiber directions or which are elongated in directions crossing wooden fiber directions, are formed in the thin wooden boards. Instead of the cutouts, it is possible to form a plurality of folded portions elongated in directions crossing wooden fiber directions. The thin wooden boards are integrally laminated together in such a way that the wooden fiber directions thereof mutually cross with a prescribed angle therebetween. The thin wooden boards integrally laminated together are subjected to thermal pressing so as to form a wooden vibrator serving as the diaphragm. Thus, it is possible to easily produce the diaphragm having a high strength and superior acoustic characteristics without causing defects.

Abstract: A diaphragm in one mode of the present invention comprises an outer shape section having a circle with one diameter, or a shape of a polygon to be inscribed in a circle with the one diameter; an inner shape section protruding in one direction with regard to a plane including the outer shape section, wherein a shape formed by projecting the inner shape section on the plane is rotationally symmetric about the central axis of the circle; and a vibrating face section linking the outer shape section and the inner shape section and having an inclined face inclined to the central axis, wherein any one of cross-sectional shapes of the vibrating face section is rotationally symmetric about an eccentric axis which is eccentric with regard to the central axis, the cross-sectional shapes being defined by a plane intersecting perpendicularly to the central axis. An electroacoustic transducer uses the above diaphragm.

Abstract: A diaphragm (6) for an electroacoustic transducer is preferably designed to be essentially rectangular and has a diaphragm inner region (20) for sound conversion and a diaphragm outer region (21) for attaching the diaphragm (6) and a diaphragm intermediate region (22) which lies between the diaphragm inner region (20) and the diaphragm outer region (21), wherein the diaphragm inner region (20) is delimited toward the outside by preferably rectilinear sides (23, 24, 25, 26) and the diaphragm outer region (21) is delimited toward the inside again by preferably rectilinear sides (31, 32, 33, 34), and wherein the aforementioned sides (23, 24, 25, 26) of the diaphragm inner region (20) are joined to rounded outer corner regions (27, 28, 29, 30) with a mean outer radius value R and the aforementioned sides (31, 32, 33, 34) of the diaphragm outer region (21) are joined to rounded inner corner regions (35, 36, 37, 38) with a mean inner radius value r, wherein the mean inner radius value r of each inner corner region

Abstract: A sound generator, particularly a loudspeaker, configured to emit sound, comprising a rigid element (2) enclosing a plurality of air compartments (3), wherein the rigid element (2) has a back side (B) comprising apertures (4), and a front side (F) that is closed, wherein the generator is provided with at least one actuator (6), for instance one or more electromagnetic actuators and/or piezoelectric elements, configured to actuate the rigid element (2) for the generation of the sound.

Abstract: A membrane for an electroacoustic transducer is disclosed, wherein said membrane (201) comprises a rigid membrane portion (202) having an edge (203); a flexible membrane portion (204) being connected to the rigid membrane portion (202) along the edge (203); wherein an exterior surface (205) of the flexible membrane portion (204) is concave in an idle state of the membrane (201) and shaped such that a change of the curvature of said exterior surface (205) contributes to an air volume shifted by the rigid membrane portion (202) when membrane (201) is excited.

Abstract: The present invention provides a dome-shaped diaphragm fabricated based on a film base of polyethylene terephthalate resin film. The diaphragm includes a first vibrating part of a dome shape or a flat shape, and a second vibrating part of an annular shape. The second vibrating part includes a peripheral portion of the film base provided around a central portion of the film base. The first vibrating part includes the central portion of the film base, a thermosensitive adhesive resin film, provided on the central portion, and a fiber sheet made of a woven fabric using carbon fiber or an embossed nonwoven fabric. The fiber sheet is layered over the central portion with the thermosensitive adhesive resin film interposed therebetween.

Abstract: A speaker diaphragm made of a resin containing a thermoplastic polymeric material is provided. The speaker diaphragm includes a changed portion formed on the diaphragm that is molded using the resin. The changed portion is formed by partially changing physical properties of the thermoplastic polymeric material for dispersing local vibrations based on a characteristic of local vibrations measured in advance.

Abstract: A complex speaker edge and asymmetric resonator panel in which the acoustic vibration damping capacity of the speaker edge varies longitudinally around the speaker edge. The resonator panel has an aspect ratio of approximately 1.3:1 or more, and is composed of top and bottom panels held in spaced apart relationship by a plurality of longitudinally extending ribs extending therebetween. The ribs extend at an angle of from approximately 5 to 35 degrees to the longitudinal axis of the panel. The angle is acoustically matched to the complex speaker edge to improve the accuracy with which said acoustic vibration is reproduced. The effectiveness of the differential damping capacity of the edge in improving the quality of sound output from a speaker assembly is determined by observing the average magnitude of the excursions of the sound level pressure versus frequency curves for comparable complex and single speaker edges, particularly in the 200 to 10,000 Hertz range.

Abstract: A loudspeaker diaphragm having a small overall height dimension, in which a dome portion has a sufficient rigidity and which is capable of realizing a stable loudspeaker operation, wherein the loudspeaker diaphragm can realize a desirable sound reproduction without noise, or the like, with a frequency response that is flat over a wide range.

Abstract: [PROBLEM] There is provided a diaphragm, and a loudspeaker unit using the same, capable of providing better low-tone characteristics than conventional ones. [SOLUTION] A loudspeaker unit of the present invention includes a base frame and a cover plate joined to each other to provide a flat casing. Arranged in the casing are a diaphragm 3 and a drive mechanism 2 for vibrating the diaphragm 3. The diaphragm 3 consists of a rectangular area 30a and a pair of semielliptic areas 30b, 30b spreading rightward and leftward from the rectangular area 30a, and has an elliptic central portion 31 having its major axis in the longitudinal direction of the diaphragm 3 and a peripheral portion 32 spreading around the central portion 31. The central portion 31 includes an adhesive layer 33 for fixing a coil 21, laid on a central area of a diaphragm body 30, and is formed thicker than the peripheral portion 32.

Abstract: The present invention provides a loudspeaker diaphragm and an electrodynamic loudspeaker of an elongated shape being shorter in the minor-axis direction than in the major-axis direction, which have a desirable sound reproducing capability with a high efficiency and are not significantly influenced by divided vibrations of an elongated loudspeaker diaphragm, and which are suitably installed in devices such as display devices.

Abstract: A diaphragm body (12) is provided with a plurality of slits (14, 14a) extending from the central part thereof toward the outer circumference. The slits (14, 14a) are filled with a low-elasticity filling material composed of a material different from that of the diaphragm body (12). The slits (14, 14a) are extended rectilinearly or curvedly. The filling material (15) has a Young's modulus lower than that of the principal material of the diaphragm body (12) and/or an internal loss larger than of the principal material of the diaphragm body (12). Furthermore, the filling material (15) employs UV ray and/or visible ray curable resin or thermoplastic resin. Alternatively the filler (15) may be a porous material or a foamed material. The diaphragm body (12) produced by filling the slits (14, 14a) with the filling material (15) is employed for constituting a loudspeaker.

Abstract: A diaphragm in one mode of the present invention comprises an outer shape section having a circle with one diameter, or a shape of a polygon to be inscribed in a circle with the one diameter; an inner shape section protruding in one direction with regard to a plane including the outer shape section, wherein a shape formed by projecting the inner shape section on the plane is rotationally symmetric about the central axis of the circle; and a vibrating face section linking the outer shape section and the inner shape section and having an inclined face inclined to the central axis, wherein any one of cross-sectional shapes of the vibrating face section is rotationally symmetric about an eccentric axis which is eccentric with regard to the central axis, the cross-sectional shapes being defined by a plane intersecting perpendicularly to the central axis. An electroacoustic transducer uses the above diaphragm.

Abstract: A diaphragm in one mode of the present invention comprises an outer shape section having a circle with one diameter, or a shape of a polygon to be inscribed in a circle with the one diameter; an inner shape section protruding in one direction with regard to a plane including the outer shape section, wherein a shape formed by projecting the inner shape section on the plane is rotationally symmetric about the central axis of the circle; and a vibrating face section linking the outer shape section and the inner shape section and having an inclined face inclined to the central axis, wherein any one of cross-sectional shapes of the vibrating face section is rotationally symmetric about an eccentric axis which is eccentric with regard to the central axis, the cross-sectional shapes being defined by a plane intersecting perpendicularly to the central axis. An electroacoustic transducer uses the above diaphragm.

Abstract: A suspension with a plurality of roll sections each of which has a semi-cylindrical shape from a cross-section view. The roll sections are disposed side by side based on a straight line connecting two points on an inner periphery or an outer periphery. The roll sections form a closed loop in a manner that a roll section of the roll sections being disposed first adjoins a roll section of the roll sections being disposed last. Adjacent roll sections are coupled with each other through a boundary section forming a continuous three dimensional curved surface. A linearity of compliance improves, and generation of distortion or rolling is restricted using the suspension.

Abstract: Diaphragm (9) has through-hole (10) for fixing a voice coil at its center part, and has a fixing part of edge (12) at its outer periphery whose shape is substantially circular. The shape of the outer periphery of diaphragm (9) is formed as follows: first circle and second circle (9A, 9B) are overlapped each other with their center points (9a, 9b) displaced in such a manner that at least one part of an outer periphery of first circle and second circle (9A, 9B) forms a part of the substantially circular outer periphery of an entire shape. Signal reproduction characteristics can be flattened as much as possible by reducing a resonance level.

Abstract: A preferably elongated loudspeaker (LS), which preferably comprises a cylindrical moving coil (SP) and an elongated diaphragm (M) with an elongated fastening part (B) and an annular retaining part (H) lying within the fastening part (B), and with corrugations (S1) extending in radial directions, wherein the diaphragm (M) comprises an arrangement for reducing its stiffness in at least one narrow region (SM1, SM2), which arrangement is present between the fastening part (B) and the retaining part (H). In a preferred embodiment comprising an arrangement of the corrugations (S1) in the at least one narrow region (SM1, SM2) the corrugation density is smaller than the corrugation density in at least one wide region (BM1, BM2). Preferably, the diaphragm (M) furthermore comprises an additional corrugation (S2) in the at least one narrow region (SM1, SM2), which additional corrugation (S2) extends transversely to radial directions.

Abstract: A resin-molded component such as a loudspeaker diaphragm, in which rigidity is enhanced while light weight and high specific modulus of elasticity are maintained, is formed by applying carbon dioxide gas with a predetermined pressure to a thermoplastic resin in which crystallization is facilitated in the resin flowing direction to fill a mold. After the resin is filled, injection molding is performed by somewhat moving the mold to form five layers of: oriented minute-foaming layers, having approximately cylindrical foams, the length of which is twice the diameter thereof in the resin flowing direction in the mold, an unfoamed core layer positioned between both the foaming layers, and unfoamed skin layers formed on the front and rear surfaces.

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 square speaker is disclosed having a novel surround with a novel rounded corner design and with a magnet assembly and former sized, shaped, and arranged to exploit the increased excursions enabled by the novel surround. The arcuate portion of the rounded corner features smoothed trapezoidal circumferential undulations of the radially outer portion and an extension pad forms the arcuate portion of the radially inner portion of the rounded corner. An apex groove separates the inner portion from the outer portion. Tapered protrusions of the outer portion flank the smoothed trapezoidal circumferential undulations. The rounded corner is bounded by edges making angles of between 20 degrees and 40 degrees (preferably about 35 degrees) with straight sides of the square surround. Most of the outer perimeter of the entire inner flange adjoins the inner portions of the rounded corners. Significant increases in volume displacement per speaker size are achieved.

Abstract: The invention is a suspension element having an outer edge and an inner edge. The suspension element, such as a spider or surround, varies in shape along at least a portion of the suspension element to help relieve both the radial and tangential stress placed on the suspension element when it is stretched. The shape employed in the suspension element allows the suspension element to stretch more easily, creating a higher performance speaker of the same size by increasing the diaphragm excursion and voice coil movement.

Abstract: The speaker has a diaphragm main body 30 supported resiliently on a frame 23 via an edge portion 31 around its outer circumference, and the groove ribs 35 integrally formed in the edge portion 31, wherein a regulation member 37 for partially improving a flexural strength of the edge portion 31 is provided on a part of the front or back face of the edge portion 31.

Abstract: A planar diaphragm loudspeaker for use in a suspended ceiling grid and related methods of manufacturing are provided. The loudspeaker includes a rectangular, planar diaphragm of polymer material sized to fill an opening of the ceiling grid. The front surface of the diaphragm defines a three-dimensional, textured pattern formed by a secondary operation, such as, etching, perforating, and adhesion of granular or fiber material. The diaphragm may include an outer region about the periphery of the diaphragm having a density of at least 5 pcf and an inner region circumscribed by the outer region, thereby providing sufficient structural stiffness to the outside perimeter of the diaphragm and eliminating the need of an outer frame. The density of the inner region is at or below about 3 pcf throughout the inner region. Also, a shroud may secured to the diaphragm, in which the shroud and the diaphragm are securable in a first orientation for flush mounting or in a second orientation for tegular-drop mounting.

Abstract: The present invention relates to an electro-acoustic transducer suitable for applications within mobile communication equipment and hearing aids. The transducer comprises two diaphragms positioned on opposite sides of a magnetic circuit having two magnetic gaps. When used as a microphone the transducer is substantially insensitive to vibrations, and when used as a speaker the transducer generates only very low vibration levels. The magnetic circuit has a number of advantages compared to conventional transducers with circular magnetic. The transducer can be made lightweight and with very compact dimensions compared to conventional designs. In a preferred embodiment the diaphragms are rectangular. The transducer may additionally be used as a vibration generator for silent alarm signals.

Abstract: A loudspeaker diaphragm affixed with a coil includes an edge portion located outside of a portion affixed with the coil and a center portion located inside of the portion affixed with the coil. The center portion is provided thereon with ribs. With these ribs, the height of the center portion can be limited to the height of the ribs. Therefore, it is possible to save a space of a loudspeaker where the loudspeaker diaphragm is placed, thereby slimming down the loudspeaker. Furthermore, with these ribs, the rigidity of the center portion can be improved without using a conventional solution of forming, for example, a dome shape on the center portion.

Abstract: An annular surround for a loudspeaker cone wherein a radial cross-section of the surround varies around the circumferential extent of the surround, so as to accommodate peripheral expansion or contraction of the surround by bending. Thus a trough shaped cross-section of the surround may vary sinusoidally with angle around the polar axis of the surround between a semicircular and semielliptical cross-section. The trough section may bland to an adjacent portion of the surround by a fillet which also varies sinusoidally in cross-section in phase with the variation of the trough.

Abstract: A tweeter with a light, thin sandwich plate which can be excited into multiple reflected bending waves, and a driver which makes a vibrating contact and excites the sandwich plate, where the driver is designed for higher sound frequencies and the sandwich plate for propagating bending waves with low damping. The sandwich plate is freely carried with low damping by holding elements, where the latter are designed to be low damping at higher sound frequencies.

Abstract: A speaker diaphragm 10 is provided having an improved quality of radiation sounds and a good outer appearance. The speaker diaphragm has in its slanted area projections typically represented by a peak line 4 and recesses typically represented by a bottom line 5. The projection typically represented by the peak line extends radially from the central area to the edge portion, and curves along the circumferential direction as it comes near to the edge portion. While the speaker diaphragm 10 vibrates at a large amplitude and moves toward the bottom side thereof, a rotation force is applied to air which is likely to concentrate upon the central area to thereby lower the air pressure to the central area. The speaker diaphragm 10 has a three-dimensional structure like a screw propeller so that the mechanical strength of the speaker diaphragm 10 can be increased over the whole area thereof and division vibrations can be suppressed.

Abstract: An audio speaker including a chassis and a diaphragm defining an axis. A suspension movably interconnects the diaphragm and the chassis for reciprocating movement of the diaphragm along the axis. A motor is operably connected to the diaphragm for powered movement thereof. The diaphragm includes a cylindrical flange extending from its peripheral edges axially in the direction of the motor. The termination of said cylindrical flange provides an attachment for an annular rear flexible suspension member that, in turn, attaches to the frame.

Abstract: The invention is a suspension element having an outer edge and an inner edge. The suspension element, such as a spider or surround, varies in shape along at least a portion of the suspension element to help relieve both the radial and tangential stress placed on the suspension element when it is stretched. The shape employed in the suspension element allows the suspension element to stretch more easily, creating a higher performance speaker of the same size by increasing the diaphragm excursion and voice coil movement.

Abstract: A piezoelectric speaker includes a piezoelectric vibrator and a metal reflection plate. The piezoelectric vibrator includes a piezoelectric element which has a dome shape with a hollow portion and which is polarized in the thickness direction, a first electrode disposed on the inner surface of the piezoelectric element, a second electrode disposed on the outer surface of the piezoelectric element. The piezoelectric vibrator further includes a hole provided in the top thereof. The reflection plate is arranged to cover the hollow portion of the piezoelectric vibrator.

Abstract: An electro-acoustic converter, comprising a barrel shaped diaphragm (2) formed about a longitudinal axis (3) and comprising first and second annular opposed ends (4, 5), and a first electrically driven vibration generator (6-11) for inducing a vibrational movement in the first annular end in the direction of the longitudinal axis.

Abstract: The present invention is directed to an electroacoustic transducer, which is capable of controlling a particular vibration mode having large amplitude generated in a diaphragm and reproducing and outputting with fidelity a sound signal transmitted to the diaphragm.

Abstract: A fire protective flat panel radiator assembly for installation in a suspended ceiling grid is provided. The assembly includes a flat panel radiator having a frame that supports a sonic diaphragm, which is driven by a transducer to reproduce an audio program. A back box is mounted to the radiator and the back box covers and encloses the diaphragm and other fire susceptible components of the radiator. The back box is provided with a cut-out portion that is covered with an air pervious panel, which is resistant to fire hazards but that allows air flow in and out of the back box. In one embodiment, the radiator has a bridge and the back box is formed by a pair of shells mounted on each side of the bridge to enclose and protect the diaphragm. The result is a fire protected flat panel radiator assembly that meets the fire performance requirements for air handling plenums while retaining the sonic fidelity of a flat panel sound radiator without a fire protective back box.

Abstract: A planar diaphragm loudspeaker for use in a suspended ceiling grid and related methods of manufacturing are provided. The loudspeaker includes a rectangular, planar diaphragm of polymer material sized to fill an opening of the ceiling grid. The front surface of the diaphragm defines a three-dimensional, textured pattern formed by a secondary operation, such as, etching, perforating, and adhesion of granular or fiber material. The diaphragm may include an outer region about the periphery of the diaphragm having a density of at least 5 pcf and an inner region circumscribed by the outer region, thereby providing sufficient structural stiffness to the outside perimeter of the diaphragm and eliminating the need of an outer frame. The density of the inner region is at or below about 3 pcf throughout the inner region. Also, a shroud may secured to the diaphragm, in which the shroud and the diaphragm are securable in a first orientation for flush mounting or in a second orientation for tegular-drop mounting.

Abstract: The speaker has a diaphragm main body 30 supported resiliently on a frame 23 via an edge portion 31 around its outer circumference, and the groove ribs 35 integrally formed in the edge portion 31, wherein a regulation member 37 for partially improving a flexural strength of the edge portion 31 is provided on a part of the front or back face of the edge portion 31.

Abstract: A loudspeaker diaphragm 104 affixed with a coil 103 includes an edge portion located outside of a portion affixed with the coil 103 and a center portion located inside of the portion affixed with the coil 103. The center portion is provided thereon with ribs 202. With these ribs 202, the height of the center portion can be limited to the height of the ribs 202. Therefore, it is possible to save a space of a loudspeaker where the loudspeaker diaphragm is placed, thereby slimming down the loudspeaker. Furthermore, with these ribs, the rigidity of the center portion can be improved without using a conventional solution of forming, for example, a dome shape on the center portion.

Abstract: In a speaker including a voice coil which is wound on a voice coil bobbin and is inserted into a magnetic circuit gap of a magnetic circuit, and a cone which is coupled to the voice coil bobbin for vibration, the cone (16) is constructed of two divided cones: a drive cone (16A) linked to the voice coil bobbin (14) and a cone paper (16B) linked through an edge (17) to a frame (F).

Abstract: A damper 3A is provided with an inner peripheral waveform portion 11 and an outer peripheral waveform portion 12. A flat portion 10 is provided between the inner peripheral waveform portion 11 and the outer peripheral waveform portion 12. When the damper is used for a loudspeaker, the flat portion 10 does not elastically deform in a radial direction R, so that linearity of the damper 3A in a vibrating direction Z is ensured by elastic deformation of the waveform portions. In addition, a rolling phenomenon of a voice coil bobbin and a diaphragm can be suppressed.

Abstract: A method of producing cone diaphragm having color patterns includes steps of using a fiber-made thin sheet as a base material; printing the base material with a high molecular ink; soaking the printed base material in a high molecular resin material; or alternatively, first soaking the base material in the high molecular resin material and drying the base material, and then printing the base material wish the high molecular ink; so that the base material is coated with a layer of the high molecular resin to maintain a desired brilliance of the color patterns; drying the base material and positioning it in a high-temperature mold, so that the base material is molded into a cone having a predetermined shape; painting outer surfaces of the molded cone with a paint; and trimming the molded and painted cone to produce a finished cone diaphragm having color patterns.

Abstract: An entertainment sound panel that serves foreground music and paging applications. The entertainment sound panel of the present invention is constructed of honeycomb materials and adhesives. The driver of the entertainment sound panel is mounted and supported on a bridge structure that spans the entertainment sound panel on its back side. The driver interacts with the panel through the voice coil assembly. The driver is separated from the entertainment sound panel by a contact pad to deal with the shear problems between the sound panel and driver. Improvement in low frequency (bass) response is provided by a butt joint that lays next to an adjacent isolation pad, and can float freely. In another embodiment, the present invention provides a lower cost flat panel sound radiator for low end business applications where the performance characteristics of the radiator are less important than the cost. The low end flat panel radiator is constructed from a polypropylene or similar material.

Abstract: A passive radiator and method is disclosed which improves frequency response linearity and greatly reduces the possibility that wobble of a passive radiator which will occur without the displacement limitations of a spider containing speaker structure. Two substantially flat surfaced speaker diaphragms are tied together and supported by two sets of surrounds oriented in opposite directions to reduce the non-linearity in the surround spring rate and improve low frequency sound generation. A vent (pressure relief) system is provided to improve the frequency response and range of motion of the passive speaker system. A progressive surround roll arrangement provides for improved sound quality by utilizing localized position based extension while maintaining the range of maximum travel during resonance.

Abstract: The invention concerns the embodiment of panel loudspeakers working according to the bending wave principle. Said loudspeakers are generally formed by at least one acoustic panel (11) and at least one driver (12), the driver (12) being connected to the acoustic panel (11). When such acoustic panels (11) are used for reproducing low frequency audio signals, the acoustic panel (11) must be arranged in sufficiently large sound walls in order to exclude the occurrence of an acoustic short circuit between the front part and the back part of the panel. Apart from being costly, only one side of the sound walls is actively used for sound generation as a result of the separation of both acoustic panels (11). Hence, the invention aims at providing a panel loudspeaker (10) that does not require any additional sound walls in order to exclude the occurrence of an acoustic short circuit while at the same time enabling full utilization of the surface of the acoustic panel (11) for sound generation.

Abstract: The invention described herein is a low-mass, light-weight sound generator with particularly good performance at mid and low audio frequencies. It is expected to find principal use in applications where mass is of crucial importance. It is capable of delivering the high acoustic levels, as required for sound generation or active sound control. The present invention uses a generally planar acoustic membrane as a diaphragm, the diaphragm being in tension and attached at its outer edge to a support frame which provides a soft boundary condition to the acoustic diaphram. In a preferred embodiment, the support structure is an inflatable toroidal tube of rubber or rubber-like material. A polymer membrane is attached to the support structure by heat sealing the membrane in place. A voltage is applied to a piezoelectric bender-type actuator, which imparts axial displacement to a region of the diaphragm, causing resonance of the diaphragm in the desired frequency range.

Abstract: A panel-shaped loudspeaker includes a panel (1) and an exciter coupled to the panel. The panel is provided with two parallel extending thin walls (1a, 1b) which are interconnected by a structure of thin strip-shaped partitions (1c) situated between the walls. The longitudinal axes of all partitions extend parallel to each other and give the panel an anisotropic bending stiffness. The material of the walls and the partitions of the panel has an internal damping which is at least 2.5% of the critical damping of the relevant material, used in the panel.

Abstract: A panel speaker includes an acoustic vibrating plate, and a vibration driver mounted off a center of the acoustic vibrating plate and applying vibration to the acoustic vibrating plate. A control unit may be provided to control the vibration driver to apply vibration to the acoustic vibrating plate.

Abstract: The invention concerns a method for making a material absorbing surface mechanical wave generated by local waves capable of producing interference phenomena relative to the pressure wave with propagation direction orthogonal to said surface. The method consists in forming a support (S) delimiting the surface from a continuous structure, said support having a specific rigidity in a direction substantially orthogonal to said support (S). An sound-absorbing coat (R) is then formed on at least one surface of the support (S), said coat comprising a plurality of obstacles to the propagation of the surface mechanical wave and the local waves, which are thus absorbed. The invention is useful for making diaphragms for electro-acoustic transducers and high quality electro-acoustic transducers.

Abstract: A diaphragm of electroacoustic transducer has an edge formed with alternately up-rolled and down-rolled portions with respect to vibration plane of the diaphragm and disposed at regular intervals in circumferential direction and with sloped-plane portions respectively connecting rims opposing above and below of adjacent ones of the up-rolled and down-rolled portions, the sloped-plane portions extending in respective tangential lines with respect to an inner periphery of the edge and intersecting the circumferential direction at an alternately opposite angle with respect to the vibration plane.

Abstract: A frame (14) supporting a diaphragm (12) by its outer periphery is constructed by a connecting ring (30) and a base (28) which comprises a bottomed cylinder portion (28A) and a mounting portion (28B) which extends radially outward from the bottomed cylinder portion (28A) which is a part of the magnetic circuit unit (18). The connection is achieved by the caulking of the ring (30) and the mounting portion (28B) with the diaphragm (12) clamped therebetween.