Abstract: A composite loudspeaker diaphragm is disclosed having first and second substantially flat carbon fiber skins, and a honeycomb core sandwiched between the first and second carbon skins. In a preferred form, each carbon fiber skin comprises a sheet formed of primarily unidirectional carbon filaments bound together by an epoxy resin. In the preferred embodiment, the honeycomb core is formed of nomex, and is glued with epoxy to the first and second carbon skins, and then heated. The sandwich diaphragm is manufactured so that the direction of the carbon fibers of the cross plies of each outer skin are out of phase relative to each other, preferrably in the range of approximately ninety degrees. The improved diaphragm is used in an flat-panel loudspeaker system having improved performance at higher frequencies.

Abstract: The cone of a speaker which has fibers perpendicularly fastened thereto by an electrostatic fiber implanting apparatus to eliminate the reflection of transverse waves between the diaphragm and the peripheral flange of the cone.

Abstract: This invention provides an acoustic vibrational material containing various fibers as the reinforcement material and having the epoxy resin as the matrix resin, wherein the epoxy resin is modified by a polybutadiene base elastomer containing not less than 90 mole percent of 1,2-linked units. The epoxy resin modified with the above polybutadiene elastomer exhibits a maximum value of loss coefficient at the temperature region near the room temperature. This region is much higher than that of the conventional epoxy resin modified with polybutadiene elastomer mainly including 1,4-linked unit. Decrease in elastic modulus of the epoxy resin with increase of temperature is lesser in the epoxy resin of the present invention, whereas larger in the conventional one. Thus compatibility between large internal loss and high elastic modulus is achieved.

Abstract: A diaphragm of an electroacoustic transducer is made of a material including fibers taken out of young stems of bamboo grasses and preferably, used as the material is paper made by mixing the fibers taken out of young stems of bamboo grasses and wood pulp in a predetermined ratio. Containing fibers taken out of young stems of bamboo grasses allows rigidity and internal loss characteristics of the diaphragm to be enhanced without increasing its density, thereby expanding a frequency band of the diaphragm. In addition, young stems of bamboo grasses can be gathered without affecting parent bamboo grasses, which prevents destruction of the environment.

Abstract: An acoustic diaphragm employed in a speaker or the like and a method for producing the acoustic diaphragm are disclosed. A diaphragm substrate is a diaphragm exhibiting air permeability such as a paper diaphragm. The substrate is processed with filling by microfibrilated pulp. For filling, the substrate is immersed in the liquid dispersion of the microfibrilated pulp and the pulp is deposited on the substrate under suction. When the microfibrilated pulp is deposited on the substrate under suction, any voids present in the substrate are closed by the microfibrilated pulp so that air tightness is improved without lowering the sound quality or detracting from desirable properties of the diaphragm, such as low density, high toughness and low losses.

Abstract: The present invention relates to a diamond vibration plate for a speaker having high sound velocity or E/.rho. and which is superior in high-pitched tone performance. Conventional, diamond vibration plates which are made overall from crystalline diamond were apt to split or break at a flange due to the high rigidity. According to the present invention periphery of the flange is circularly cut by laser beams to eliminate rugged circumference. The laser treatment also converts the crystalline diamond of the flange into non-diamond carbon. The resulting vibration plate with a central spherical part of crystalline diamond and a periphery of a flange of non-diamond carbon excels both in high frequency property and mechanical strength.

Abstract: Process for the preparation of films or diaphragms for acoustic applications, exhibiting improved vibration properties, and films or diaphragms obtained by this process, particularly diaphragms for electro-mechanical transducers, particularly for loudspeakers. The invention has for an object a process for preparing films or diaphragms for acoustic applications exhibiting improved vibration properties, consisting in preparing a dispersion, in a liquid, of at least one macropolymer, especially at least one synthetic macropolymer having at least 30,000 atoms in a molecule, adding, to the dispersion, a product capable of swelling said macropolymer and of transforming said dispersion in a gel of similar material, and drying sale gel or similar material by evaporating substantially all the liquid from the gel or similar material, thereby obtaining the film or diaphragm in the porous solid slate. NO DRAWING.

Abstract: An acoustic diaphragm comprising two or more laminated composite sheets, being formed into a shape with a curved surface. The composite sheet is made up of sliced wood and nonwoven fabric cloth consisting of adhesive resin, being stuck on backside of the sliced wood. Thus, it is capable of forming a three-dimensional shape, making use of natural wood characteristics, and improving unevenness of natural material properties. In one preferred embodiment, the diaphragm is woven of slit wood or other article forming the weft and synthetic or inorganic fibers forming the warp.

Abstract: A conical loudspeaker (10) has a dust protection cap (23) of hot-pressed polymer foam. Dust protection caps (23) made from this material are largely insensitive to finger pressure and can be attached to the conical speaker membrane using simple adhesives. Preferably the outer rim of the conical speaker membrane is secured by a lock beading (14) made from the same foam as the dust protection cap (23). This has the advantage that if the pressing die is suitably configured, the dust protection cap (23) can be made from the portion of the foam mat that otherwise, if only a lock beading (14) was being produced, would be left over in the center of the foam mat.

Abstract: An acoustic diaphragm is obtained by forming micro-fibrillated cellulose into a web by a process similar to a paper-making process. The micro-fibrillated cellulose is the cellulose obtained by beating to the Canadian standard freeness of not more than 300 ml, or bacterial cellulose. Since the micro-fibrillated cellulose is poor in wet strength, it is reinforced by a reinforcement element and, in this state, is formed into the web on a wire screen. The reinforcement element may be detached after forming the web, or may be left laminated with the cellulose web so that the resulting composite product is used as the acoustic diaphragm.

Abstract: A cone formed from paper such as used in speaker as a diaphragm, wherein the wing portions, which may function to reinforce the cone, are selectively arranged and extending from any point in the periphery of the larger diameter circle to any point in the smaller diameter circle of the cone which has a frusto-conical shape and a coating layer is applied to the entire surface of the cone, and a method for making a cone using a sheet of paper, wherein the method comprises steps of cutting a sheet of paper into a desired pattern simultaneously with seaming at least a pair of folding portions composed of a centeral folding line and two lateral folding lines equi-angularly and symmetricaly displaced to each side of the center line, forming wing portions by folding said lines, honding the facing surfaces of the folded portions and, coating the entire surface of the entire surface of the cone with moisture-proof material.

Abstract: A speaker diaphragm has a laminated construction in which a core layer is made of a porous diamond type wafer or wafers and sandwiched by a pair of surface layers made of diamond type material. Presence of numerous small pores in the core layer reduces the specific gravity of the entire diaphragm, thereby increasing efficiency in acoustic conversion. The porous construction of the core layer reduces internal loss of the diaphragm, and suppresses resonance in the treble range.

Abstract: A speaker diaphragm includes a combined fiber paper made with crushed silk chips and a crushed bast fiber. In the preferred embodiment, the bast fiber is a natural Manila hemp fiber. The silk fiber contributes vibration damping to the diaphragm while the bast fiber contributes strength and stiffness. The crushed silk chips and the crushed bast are mixed with water to produce a slurry from which the water is drained to produce the combined fiber paper. In a further embodiment of the invention, a layer of a different material is disposed between two layers of the combined filter paper. The layer of different material is selected from a hard wound silk gauze, a glass fiber, a polyamid fiber and a carbon fiber.

Abstract: A diaphragm formed of a material for molding mainly composed of a uniform mixture of an ultra-high molecular weight polyolefin with a high melting viscosity and a polyolefin with a lower melting viscosity, wherein the ultra-high molecular weight polyolefin is extensively oriented by the lubricating action of polyolefin having the lower melting viscosity and the method for producing the diaphragm. The diaphragm superior in specific modulus of elasticity and internal losses may be produced by producing the polyolefin composition by multi-stage polymerization and injection molding the composition for radially orienting the molecular chains of the ultra-high molecular weight polyolefin.

Abstract: Disclosed are a speaker diaphragm formed from a polyamide resin reinforced with continuous fiber reinforcements and/or long fiber reinforcements, and a production method therefor. The speaker diaphragm has high internal loss and excellent specific modulus so as to produce a large sound volume, and has reduced high frequency distortion, flat frequency characteristics and reduced sound distortion for the capability of faithfully reproducing low volume sound.

Abstract: A process for preparing a wholly carbonaceous integrated diaphragm for acoustic equipment use comprises blending under application of high shearing force a mixture of one or more kinds of organic high polymeric substances carbonizable on baking and powder of graphite with crystals high elastic modulus developed therein; extrusion-molding the uniformly blended and dispersed mixture through a profile extrusion die to give a core material with orientation along the direction of the extrusion and to be cut to a desired form; independently blending and sheeting under application of high shearing force the mixture with the organic powder oriented to high degree parallel to the direction of the surface of the sheet and further passing the sheet through a calendering roll to give a skin material in the form of a film or sheet; bonding said skin material on both sides of the core material by the use of such organic liquid composition that provides high yield of carbon residue on baking and then baking the resulting un

Abstract: A speaker diaphragm is formed by heat-pressurized molding a composite structure of fabric cloth and resin sank into the fabric cloth. The fabric cloth is woven from high strength and high elasticity polyethylene fiber which has at least tensile modulus of 4,500 kg/mm.sup.2 (500 g/d).

Abstract: A diaphragm for an electroacoustic transducer comprising stratiform mineral of layers into which a hardener or an agent for facilitating hardening is adsorbed between the layers, thermosetting resin monomer, and carbonfibers which constitute a composite material which is formed under heat and pressure. The diaphragm is increased in rigidity which is required as physical properties therefor and is easy in forming.

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: An electro-acoustic transducer comprising a diaphragm (1) and means for shifting the high-frequency roll-off of the frequency-response characteristic of the transducer towards lower frequencies. This is accomplished by making the diaphragm (1) permeable to air, the permeability to air over the entire surface area of the diaphragm being such that at least a passage of 50 liters of air per second per square meter is obtained for a pressure difference of 200 Pa (=200 N/m.sup.2) between opposite sides of the diaphragm.

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 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: A speaker provided with a diaphragm having a foamed resin body of relatively low density on its front surface includes a thin sheet of foamed resin applied to its surface. The thin sheet of foamed resin has relatively high flexural rigidity and is impermeable to air, to enable the surface of the foamed resin body to be protected against damage or indentation that might otherwise be caused. The thin sheet of foamed resin may be coated with a paint or have a foil applied to its surface. The speaker has improved electroacoustic transducing efficiency.

Abstract: A flame retardant diaphragm for speakers, etc. comprises an admixture of natural fibers and inorganic fibers. The admixture is impregnated with a thermosetting resin and an organic bromine compound, and heat-treated under pressure. The organic bromine compound acts as a flame retarder.

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: A flame-retarded speaker diaphragm is prepared by making a cone from cellulose fibers, impregnating the cellulosic cone with a solution of a trimethylol melamine monomer, an organic phosphorus- and nitrogen-containing compound, and a trialkyl amine catalyst in an alcohol solvent, and heating the impregnated cone until the solvent is removed and the melamine resin is cured. Flame retardancy is imparted to the cellulose cone-shaped diaphragm without the sacrifice of its frequency response.

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 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: The disclosure is of a high performance speaker diaphragm which comprises needled and interlocked textile staple fibers of a first, relatively heat-resistant fiber and a second, heat-softenable fiber. The fibers are molded together to soften the second fiber whereby it interlocks with the first fiber.

Abstract: A diaphragm for electro-acoustic transducer comprising a core member of honeycomb structure made of either a thin film of a metal or a high molecular material, and a skin member bonded to at least one side of this honeycomb core structure and being prepared by the use of aromatic polyamide fibers having a high tensile strength, a high Young's modulus and a high Young's modulus-to-weight ratio and reinforced by a thermo-setting resin. Such diaphragm has a high Young's modulus, an improved mechanical strength and a wide frequency range of piston motion, and presents reduced distortion throughout a wide frequency range, and has a superior transition characteristic, whereby a good sound reproduction characteristic is obtained.

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: 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: 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: A diaphragm for a loud speaker is manufactured by impregnating a diaphragm blank made of natural or man-made fibers or formed by molding a synthetic resin, with a water-soluble inorganic flame retarder, and thereafter with an aqueous solution of a fluorine containing water repellent and oil repellent agent, and then by heating and molding into a speaker diaphragm.

Abstract: A vibratory plate of pulp and chopped carbon fibers mixed uniformly in the paper. The pulp is thoroughly beaten to a degree not higher than 300 cc. of Canadian standard freeness.