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 loudspeakers and the like comprises a diaphragm base component formed of ceramics of a three-dimensional network structure so as to be light in weight, high in bending stiffness, easy to make and high in sound velocity. The diaphragm base component is sealed by a sealing material so as to be made air-permeable. This diaphragm is made by impregnating combustible foamed plastics material with a ceramic slurry, baking the ceramic impregnated foamed plastics to burn off the foamed plastics material, and the diaphragm base component sealing with the sealing material.

Abstract: A loudspeaker diaphragm comprising a molded, sintered ceramic body is described. The body is made of ceramic crystalline particles whose maximum size is below 1/5 time a thickness of the body which is in the form of a dome or cone. The dome- or cone-shaped diaphragm may have a flange along an opening side thereof in order to prevent deformation as may occur during firing.

Abstract: An acoustic diaphragm formed of beryllium or an alloy composed mainly of beryllium. Said diaphragm has a crystal structure having its plane (1120) preferentially orientated in parallel with the surface of the diaphragm.

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: An electro-acoustic transducer has a diaphragm which comprises a layer of a polymethacrylimide foam having a modulus of elasticity between 15.times.10.sup.6 and 120.times.10.sup.6 N/m.sup.2 and a density between 10 and 80 kg/m.sup.3. If the diaphragm has a sandwich construction, the core layer is made of said polymethacrylimide foam and the skin layers are made of glass fibres, carbon fibres, cellulose fibres or polyaramide fibres. This results in a transducer having a higher efficiency and a lower distortion.

Abstract: A diaphragm for electrostatic and electrodynamic microphones which has a distinct directional pattern comprises a taut diaphragm having a thickness of less than 8 microns and a diameter of 10 millimeters at most and which is made of an elastically extensible rubber base material which has a natural frequency of 1,200 Hz to 1,500 Hz at most. A diaphragm is particularly for microphones of the cardioid, supercardioid and hypercardioid and figure eight type.

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 moving coil loudspeaker having a cone (14) made of homopolymeric polypropylene which is stiffened by the incorporation of from 20% to 40% mineral filler such as talc or chalk, possibly also up to 5% carbon black filler, and preferably is additionally rigidified at the cone center by a stiffening ring (21) of nylon or like hard plastics material. A further feature of the invention resides in the provision of a metal former (22) carrying lapping paper (25) at the joint with the cone.

Abstract: A diaphragm for an electro-acoustic transducer comprising a sheet formed from a mixture of a polymer and mica, where the sheet contains (a) 30 to 95% by weight of a polymer selected from among polyolefins, polyesters, and polyamides and (b) 5 to 70% by weight of mica having a weight-average flake diameter not exceeding 500 microns and a weight-average aspect ratio of at least 10. By adding the specified mica, the sheet has a drastically improved dynamic modulus and a substantially unchanged loss tangent.

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: An acoustic vibrating element, such a domed speaker diaphragm A or a phonographic pickup cantilever B, is formed by vapor deposition on an easily separable mold member 5 of tantalum or tantalum alloy when a mixture of a hydrocarbon gas and an inert gas is passed through a furnace heated to a temperature of 1150.degree. C.-1250.degree. C. at a flow rate in excess of 200 cm/min. The c-axis crystalline orientation of the resulting graphite element is substantially perpendicular to its surface, which provides a Young's modulus above 16,000 Kg/cm.sup.2.

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 diaphragm for acoustic instruments such as speakers is produced by blending and kneading a thermoplastic resin such as polyvinyl chloride resin with graphite powder, rolling the blend into a sheet until graphite particles are oriented, and forming the sheet into a desired diaphragm shape. The diaphragm of the composite material containing graphite particles oriented shows an improved combination of density, elasticity and internal loss.

Abstract: Vibratory elements for use in audio equipment are fabricated from a kneaded mixture comprising post-chlorinated polyvinyl chloride and flaky graphite powder. The kneaded mixture is rolled into a sheet in which graphite flakes are oriented parallel to the surface and the sheet is then formed into a desird shape, for example, a dome- or cone-shaped diaphragm and a cantilever, as by vacuum forming, air-pressure forming or press molding. The mixture may further include polymethyl methacrylate and/or rubber-like material. The elements are characterized by improved temperature resistance.

Abstract: An improved speaker is provided for stereo headsets and the like. The diaphragm for the speaker comprises the dome of an inverted polyester film cup centered within a flurocarbon film diaphragm member. The voice coil for the speaker is wound directly about the periphery of the cup and the adhesive joint between the cup and the diaphragm comprises the sole adhesive joint of a diaphragm.

Abstract: An acoustic diaphragm for speakers having a sandwich structure constituted by a core material comprising an elongated web material bent to have a plurality of radial projections, and upper and lower surface members adhered to the upper and lower edges of the core member, as well as a method of producing the same. The acoustic diaphragm of the invention has a reduced weight while exhibiting a large flexural rigidity so that the nodal line during the resonance vibration can have a circular form which in turn offers a circular form of nodal line and increased speaker power. Also, the method of producing the invention permits easy fabrication of the acoustic diaphragm having a sandwich structure.

Abstract: A loudspeaker has a focused magnetic field and a specialized voice-coil structure, which provides constant inductance at the voice coil over the entire extent of voice coil excursion. The magnetic field is focused to a thin disc and the winding of the voice coil is of a height so that it is always in view of the thin disc of the magnetic field. The voice coil winding is not more than two layers. An extended base cross-section center pole is employed having an undercut portion forming a crown at the top. The edges of the crown are chamfered to cooperate with chamfered edges on a top plate to form the thin disc of the focused magnetic field.

Abstract: A diaphragm for an electro acoustic transducer, such as a loudspeaker, includes first and second parallel sheet members, a honeycomb core member sandwiched between the sheet members, and a damping layer interposed between each sheet member and the honeycomb core member for increasing the internal energy loss of the diaphragm.

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 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 method of producing a diaphragm of an acoustic instrument having the steps of blending powders of carbon such as graphite, carbon black or the like and a thermoplastic or a thermosetting resin, shaping the resultant blend into a desired form and then carbonizing the shaped blend. As a result, it has become possible to produce a diaphragm of an acoustic instrument, having a light weight, high rigidity and a large ratio of Young's modulus to density.

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 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: 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 including a porous diaphragm having an outside edge, an electromagnetic drive means mounted on a central area of the diaphragm for displacing the diaphragm and a hard ring forming a junction between the diaphragm and the drive means with the diaphragm being totally permeated with a stiffening material in the area between the ring and the outer edge without increasing the thickness of the diaphragm thereby improving the acoustic characteristics of the loudspeaker as compared with an equivalent unstiffened diaphragm.

Abstract: The invention discloses a loudspeaker with a diaphragm made of pulp fibers treated with a chemical condensation product of an ammonium salt of a polyphosphoric acid having a high degree of condensation with polyethyleneimine. The diaphragm has burning resistance, and the deterioration of acoustic characteristics may be prevented.

Abstract: A weatherproof loudspeaker assembly includes a box-like one-piece open-front plastic housing and a corrugated fiberboard member folded so as to line the inside of the housing with two crossed layers of corrugations on each of the walls surrounding the open front. A plastic grille plate has a plurality of slots therethrough separating forwardly projecting vanes, and a loudspeaker has a water-repellent front portion including a peripheral mounting and sealing flange mounted in watertight sealing engagement with the rear of the grille plate in surrounding relationship with the slots by means of plastic posts extending from the grille plate through holes in the loudspeaker flange and melted in place to form a rivet-like fastening.

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

Abstract: An acoustic diaphragm composed essentially of a flat, cone-like or dome-like reconstituted mica paper of fine scaly mica flakes and an organic polymeric binder impregnated in the mica paper. The diaphragm has a density of 1.3 to 2.3 g/cm.sup.3 and a Young's modulus of 6 .times. 10.sup.10 to 3 .times. 10.sup.12 dyne/cm.sup.2.

Abstract: A planar diaphragm, preferably for loudspeakers where, on the rear face side there is an asymmetrically shaped sound producing portion, surrounded by marginal and channel shaped portions to assure that sound waves generated by said sound producing portion will not trespass said portion, and said marginal portion is provided plugs of different density than said diaphragm, to modify the vibratory characteristic of the sound producing portion and thereby improve the response curve.

Abstract: A cone for a loudspeaker in which the shear function is more nearly the same at all radii, the shear function being the product of the effective axial thickness at a given radius multiplied by the circumferential length at such radius. The cone is preferably of curved or "exponential" cross section, deeply angled at a central throat but flattening out to approach a plane at the periphery. The cone is made of light, dimensionally stable material characterized by a high velocity of sonic conduction and is preferably in the form of hollow spheres of glass of small dimension in a binder of epoxy or the like. In an alternate embodiment the cone is made of a hard solid acrylic plastic in thin section and with supporting ribs to provide both rigidity and a substantially constant shear function. Encircling the cone is a flexible hinge or "surround". Interposed between the hinge and the edge of the cone is a light collar having axial rigidity to ensure that the edge of the cone remains in a planar locus.

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: The present invention comprises a radially pulsating cylindrical surface operating as a wave transmission-line. The device is responsive to electrical means and may be practically utilized to generate pressure waves. A conventional electromagnetic driving system is employed with the novel cylindrical surface. A cylindrical voice coil is affixed to the cylindrical surface co-axially. The surface may comprise a matrix of helically oriented fibers suspended in an elastomeric impregnant. Damping means may be provided both internally and terminally. The radiation produced is omnidirectional.

Abstract: An electro-acoustic transducer has a diaphragm with a moving coil. The diaphragm consists of a flat textile carrier impregnated with a highly attenuating filling material and is highly elastic in its plane but inelastic in bending.