Abstract: A method of forming diamond-like carbon layer which is advantageously adaptable as a coating layer on acoustic diaphragms. In the method, carbon vaporized out of solid carbon source is deposited onto the surface of the diaphragm as the coating layer in the atomosphere of catalystic gas, for instance, H.sub.2 +Ar or H.sub.2 of about 10.sup.-4 Torr. The deposited carbon layer on the surface of the diaphragm is an amorphous carbon of inclusion of hybridized orbital SP.sup.2 bond and hybridized orbital SP.sup.3 bond and crystalline carbon particles of hybridized orbital SP.sup.3 bond dispersed in the amorphous carbon, or an amorphous carbon of inclusion of hybridized orbital SP.sup.2 bond and hybridized orbital SP.sup.3 bond.

Abstract: A magnetic speaker equipped with a flat diaphragm comprising a straight-grain wood plate or a cross-grain wood plate, for instance, made of Sitka spruce having the specific gravity range from 0.25 to 0.8, presenting excellent acoustic properties, especially, suitable for low to medium frequency speakers. The flat diaphragm is treated to chemically modify hydroxyl groups contained in the wooden component. Modification may be by esterification, etherification, acetilation, formalinization, or the like to enhance acoustical characteristics.

Abstract: A diaphragm for use in an electro-acoustic transducer comprises a diaphragm main body only or mainly composed of natural fibers, a layer formed by laminating thereover a polyamide resin and a synthetic resin coating layer further formed to the surface of the laminate layer. The diaphragm is free from pin holes, exhibits satisfactory water proofness and excellent physical properties such as sonic propagation velocity inherent to the natural fibers. It can be fabricated with ease at a good yield and can reduce the fabrication cost.

Abstract: A felted paper loudspeaker diaphragm in which the felted paper of the annular supporting flange is thinner, and of lesser density and higher compliance than the cone body. The supporting flange is permeated with a high compliance elastomer which provides most of the tensile strength of the supporting flange.

Abstract: A loudspeaker of plane diaphragm type has a skin-like material with smaller diameter than that of the plane diaphragm pasted thereon so that the skin-like material will not stick out of the diaphragm surface and the edge piece surrounding it can securely support the plane diaphragm, preventing unpleasant noises and split vibrations.

Abstract: A diaphragm of a loudspeaker is made up of a plurality of laminated composite sheets each including a number of fibers, for example, carbon fibers having a high Young's modulus to density ratio, and a matrix bonding together the fibers. Each composite sheet is divided into a plurality of adjoining sections formed by dividing the composite sheet about the center axis of the diaphragm. The divided composite sheets are laminated such that joints between adjacent sections of one composite sheet do not overlap joints between adjacent sections of the other composite sheet. In other embodiments a similar composite sheet is spirally bonded to the outer surface of the diaphragm or rings having different diameters and made of similar composite sheet are coaxially bonded along the outer surface of the diaphragm.

Abstract: An improved diaphragm material for use with an acoustical transducer, such as a moving-coil electrodynamic loudspeaker and a loud speaker containing such diaphragm, which diaphragm comprises a formed, self-supporting, woven carbon fiber cloth material optionally having a thin air sealing plastic coating thereon, the diaphragm having a sonic velocity of about 5.times.10.sup.3 or greater and an internal loss of about 0.02 or more.

Abstract: A compression speaker driver has a relatively stiff, light weight diaphragm 11, including a dome portion and a rim portion around the periphery of the dome portion. The mounting plate 17 has an opening larger than the dome portion of the diaphragm 11, and a ring 31 is laminated to both the diaphragm 11 rim and to the mounting plate 17. Producing a composite compliance which prevents significant radial movement of the dome portion and which distributes the stress of flexing across the width of the compliance.

Abstract: A loudspeaker diaphragm is disclosed which is formed of a slurry of cellulose fibers and polypropylene fibers. In the fabrication of the diaphragm, a felt is made of the slurry, and the felt is subjected to sufficient heat and pressure to fuse the polypropylene fibers together to form a skeleton or matrix which extends through the felt.

Abstract: The present invention is directed to a diaphragm for loudspeakers which is integrally constructed through the combination of a core material being formed as a disc-shaped solid construction through the independent or series of combination of a plurality of flat-plate pieces and disc-shaped skin materials each being approximately equal in diameter on the top face and the bottom face of disc-shaped core material, the core material and skin materials being made of either boron or beryllium, thus resulting in the higher efficiency, wider zone and lower distortion of the loudspeakers.

Abstract: A multi-layer block to be developed into a disk having a honeycomb construction is initially developed into a columnar block, and then the bottom of the columnar block is radially developed for obtaining a core of a speaker diaphragm. A suitable circular thin layer is attached to the top and bottom of the core to complete a diaphragm. The columnar block may be developed by means of a cone-shaped tool into a truncated cone, and this truncated cone may be further developed into a flat disk by applying a force to the top thereof. Since the forces on development are applied to the block uniformly, the density of hexagonal sections of the honeycomb construction is uniform throughout the entire circumference of the core providing superior speaker characteristics.

Abstract: A planar diaphragm type magnetic transducer with an acoustically transparent magnetic backing, and a diaphragm overlying and spaced from the magnetic backing, the magnetic backing having magnetized strips lying parallel to each other and adjacent magnetized strips having opposite polarities at their faces confronting the diaphragm, the diaphragm being stiff and resisting flexing and connected by a flexible surround at its periphery.

Abstract: This is a vibratory diaphragm for a loudspeaker of sound appliances such as stereophonic phonographs or television receivers, which is made of composite material composed of polyimide resin, graphite granules and fabric of high strength and high modulus filaments. A vibratory diaphragm having well-balanced characteristics in the specific modulus, the internal loss, the mechanical strength, the thermal stability and the fatigue resistance is obtained. The polyimide resin gives high thermal stability, while the graphite granules greatly increase the internal loss. The fabric of high strength and high modulus filaments improves the specific modulus, the mechanical strength and the fatigue resistance.

Abstract: The invention relates to an electro-acoustic transducer using a self-supporting active radiating membrane made from a polymer material. The invention provides a transducer in which a resilient shape restoring member fixed to the case capped by the radiating membrane takes on the shape of the concave parts of the membrane, so as to oppose the definitive staving-in of the membrane by an accidental thrust force acting on the dome shaped protuberance on its outer face and restore the member to its initial shape when the force is removed.

Abstract: In an electro-acoustic transducer in a loud speaker and like devices, a diaphragm and/or a voice coil bobbin is or are formed by a composite material consisting of a foamed resin containing reinforcing fibers. Such diaphragm has a large Young's modulus-to-density ratio E/.rho., a large internal loss tan.delta. and a large flexural rigidity E.I, and thus it exhibits good characteristics in sound reproducing. Such voice coil bobbin which is an electric insulator can have a small thickness and is light in weight and has a large mechanical strength, and thus it is free from adversely affecting the vibration of the diaphragm, and accordingly, the sound reproduced.

Abstract: A speaker diaphragm assembly comprises a body made of a foam resin, and a sound radiating surface portion integrally formed with the body. In one embodiment, the sound radiating surface portion is made of a foam resin the density of which is greater than that at the body. In another embodiment, the sound radiating surface portion comprises a thin layer made of a solid resin, which thin layer is welded to the body. The rear end portion of the body may be reinforced in the same manner. In another embodiment, a supporting member is attached to the side surface of the diaphragm body for increasing the efficiency in vibration transmission from the voice coil. In another embodiment, a ring-like recess is made in the side surface of the body for spaced electrical terminals, to which heat is transmitted from the voice coil via lead wires, from the body, while a sub cone having low thermal conductivity is sandwiched between the lead wires and the body.

Abstract: The diaphragm of a speaker is supported by a viscous supporting member placed in an annular gap defined between the periphery of the diaphragm and the inner surface of a frame structure and by a conventional damper. Grooves may be made in the periphery of the diaphragm and in the inner surface of the frame structure for receiving some portions of the viscous supporting member. In another embodiment, a film made of a resin is welded to the front surface of a diaphragm body which is made of a foam resin. In other embodiments, one or more reinforcing members are fixedly adhered to both the voice coil bobbin and the flat rear surface of the diaphragm.

Abstract: A dome-shaped diaphragm for loudspeakers comprising a substrate fabric of synthetic fiber, a poly-urethane elastomer film for giving airtightness to the substrate fabric, and a viscoelastic resin adhesive adhering the fabric and the film together.

Abstract: A honeycomb shaped diaphragm for use in acoustic instruments such as speakers is manufactured by kneading a mixture of flaky graphite powder and thermoplastic resin, preferably polyvinyl chloride, rolling the mixture into a plate, forming honeycomb recesses in the plate, and mating two recessed plates with each other so that the corresponding recesses form closed cavities. The formed plate may be carbonized before assembly. The resultant diaphragm shows a high Young's modulus, a low apparent density and a remarkably high specific modulus of elasticity ensuring improved acoustic characteristics.

Abstract: A diaphragm for electro-acoustic transducer which, as a component member, utilizes a layer of ceramics material, by which the E/.rho. ratio of the diaphragm can be increased, leading to an elevated resonance frequency of the diaphragm, whereby the limit frequency for reproducting of high-pitch sound can be shifted high, thus making it possible to widen the range of piston motion of the diaphragm, and to thereby improve its frequency characteristic. Also, a diaphragm utilizing a composite board formed by lamination of a layer of ceramics material and a layer of light-weight metal eliminates the fragility of diaphragm would entail when the diaphragm utilizes a single layer of a ceramics material alone, and thus the handling of the diaphragm is facilitated.

Abstract: A diaphragm for a speaker which is prepared by heating a conjugated sheet obtained by paper-making polyethylene short fibers with other short fibers which have a high modulus of elasticity, such as carbon fiber, to melt and solidify polyethylene short fibers in the conjugated sheet; the process for the production thereof. The diaphragm for a speaker of the invention has a high modulus of elasticity and a high internal loss and a speaker prepared with such a diaphragm has the advantage of having a wider reproducing frequency response and lower distortion. Furthermore, the process for production of the invention possesses another advantage in that diaphragms for speakers can be produced in a continuous process of successively pressing out the speaker diaphragm with a cold mold press.

Abstract: An electro-acoustic transducer, such as a loudspeaker, a microphone, or the like, comprises a magnetic circuit having at least one air gap, a current conductor disposed in the air gap of the magnetic circuit to form a voice coil which is traversed by magnetic flux, and a vibratory structure mechanically coupled to the voice coil. The vibratory structure is comprised of a heat resistant film containing an epoxide-modified resin in which a heterocyclic compound containing a polyimide group is the main component. The voice coil is non-adhesively secured to the vibratory structure. For example, the voice coil is formed of a conductive substrate onto which the vibratory structure is coated and from which portions have been etched to form a generally spiral-shaped conductor. In one embodiment, the vibratory structure is a diaphragm; and in another embodiment, the vibratory structure is a bobbin having the voice coil wound thereon.

Abstract: A diaphragm for a loudspeaker includes a core member having a flat front surface from which a frustum-shaped side surface extends to a back portion, a cover member secured to the back portion and adapted to be connected to a voice coil bobbin of the loudspeaker, an outer radiation layer mounted on the front surface and having a relatively high resonance sharpness, and an intermediate layer laminated between the front surface and the outer radiation layer and having a resonance sharpness lower than that of the outer radiation layer.

Abstract: A vibrating member made of a thin metal plate and adapted to be used in an acoustic transducer such as a loudspeaker or microphone is diffused at least partially with an inorganic substance to improve the acoustic characteristics thereof, particularly the high frequency range.

Abstract: A composite diaphragm for a speaker comprises a boron layer formed on a metal foil such as titanium foil, in which a layer of a low melting point metal such as aluminum or magnesium is interposed between the metal foil and the boron layer to provide high rigidity, high elasticity and high bonding strength between the metal foil and the boron layer.

Abstract: A diaphragm for a loudspeaker includes first and second sheet members between which a core member is sandwiched and secured so that the core member has peripheral edge portions extending between the edges of the sheet members and at which the core member is of relatively low strength. A strip-like edging member, preferably of a thermosetting resin, is secured to the peripheral edge portions of the core member and to the edges of the sheet members for increasing the rigidity of the diaphragm at its periphery and preventing unwanted vibrations thereat. A damper member may be secured to the diaphragm adjacent the edging member for movably securing the diaphragm to a loudspeaker frame.

Abstract: A diaphragm for a moving evil loudspeaker is formed of a material which has a mechanical "0"value of from 7 to 12, a Youngs modulus of from 8.5 to 17.5 .times. 10.sup.5 KN/M.sup.2 and a density of from 0.85 to 1.05 g/cc. The diaphragm forming material is preferably formed of polypropylene or a propylene-containing copolymer. The diaphragm may be of cone or dome type and included are moving coil loudspeaker constructions wherein other vibrating elements, particularly spiders and outer cone support rings, are formed of the same type of material as the diaphragm.

Abstract: An electro-acoustic transducer having a flat sound radiating plane is disclosed, in which a voice coil bobbin having a voice coil wound around an outer circumference thereof is inserted in an air gap defined by an inner pole piece and an outer pole piece and dome-shaped diaphragm is inserted in the voice coil bobbin to define a front chamber surrounded by curved surfaces of an outer surface of the diaphragm and an inner surface of the voice coil bobbin, and foamed synthetic resin is filled in the front chamber.

Abstract: An acoustic diaphragm has a substrate of either a hard resin film or cloth of an organic material, and at least one side of the substrate is laid with a polyurethane elastomer layer. In the case of a cloth substrate, the cloth is optionally metallized by evaporation deposition of Al or Ti and/or impregnated with a thermosetting resin. The elastomer is a copolymer given by condensation of bifunctional polymeric alcohol and a glycol with a diisocyanate. This diaphragm features a flat response curve at medium to high frequencies on account of its relatively large value for Young's modulus and adequately great internal loss, and accordingly is particularly useful for tweeters.

Abstract: The invention relates to an electroacoustic transducer for the sound reproduction, comprising a substantially olive-shaped diaphragm body formed of a plurality of convexly pre-curved diaphragm segments capable of bending, damping material accommodated within the diaphragm body, at least one oscillation generator provided on one end of the diaphragm body and having its moving coil connected to the diaphragm body, and means for rigidly connecting the other end of the diaphragm body to the housing of the oscillation generator.

Abstract: A diaphragm for use in a loud speaker is constructed of a substrate formed into a diaphragm configuration from a thin plate or a sheet composed of an organic or an inorganic substance, and a coating layer made of boron, or, an alloy of which a major component is boron or a chemical compound of boron, being provided onto at least the surface of said substrate.

Abstract: A diaphragm for a dynamic cone speaker which is composed of a porous metal produced from a metal such as nickel, wherein a layer, such as of aluminum foil, is disposed on a surface of the porous metal to eliminate the gas permeability of the porous metal.

Abstract: A diaphragm for a dynamic cone speaker which is composed of a porous metal produced from nickel powder wherein a vinyl chloride sheet is disposed on the surface of the porous metal to eliminate the gas permeability of the porous metal.

Abstract: A loudspeaker having a diaphragm including first and second layers and a core sandwiched between the layers, the core being firmly secured to the inner surface of each layer so as to form a unitary structure therewith, a drive assembly causes the diaphragm to vibrate in accordance with a varying electrical input signal fed thereto, and a support is provided for supporting the diaphragm and drive assembly. The layers are formed of materials through which the velocity of propagation of a longitudinal wave is greater than 5000 m/sec, and the core is formed of materials having a shearing elastic modulus Gco which exceeds the value ##EQU1## WHERE E.sub.f is the longitudinal elasticity of each of the layers,t.sub.f is the thickness of each of the layers,t.sub.c is the thickness of the core, andl is the length across the surface of the diaphragm.

Abstract: This invention relates to loudspeaker diaphragms and methods of making such diaphragms. It is an object of the invention to improve damping of standing waves formed in a loudspeaker diaphragm. To this end a diaphragm in accordance with the invention is made of textile material impregnated with a stiffening material which does not completely fill the spaces between the threads of the textile material, said spaces being partially filled with damping material. The textile material is preferably a woven glass-fiber fabric or a fabric woven or knitted from an aramid fiber. The stiffening material is preferably a synthetic resin, for example, a phenolic, epoxy or melamine resin and the damping material is preferably a polyvinyl-acetate emulsion or a vinyl resin-based thermoplastic material of the kind used as a cone edge dampener.

Abstract: In assembling at least one metal frame in abutting supporting relation to a diaphragm to form a diaphragm assembly for an electro-acoustic transducer, for example, as in a microphone or headphone, the diaphragm, which may be an electret, is formed at least in part of a thermoplastic resin so as to provide the latter at each surface of the diaphragm which, in the abutting supporting relation, is engaged by a surface of a metal frame, and the frame or frames and the diaphragm are pressed together in the desired abutting supporting relation while each metal frame is heated so that heat is transmitted through the latter to melt the thermoplastic resin at the engaged surfaces of the diaphragm and frame or frames, whereupon the heating of the frame or frames is halted so that the thermoplastic resin hardens to bond together the diaphragm and frame or frames in the desired abutting supporting relation.

Abstract: A diaphragm having a flat multi-layer body with at least one layer of viscoelastic material.