Abstract: A low puff boom microphone includes a protective grid covering an end portion of the microphone housing, a microphone capsule near the protective grid, a layer of material between the protective grid and microphone capsule, a spacer between the layer of material, and an open area laterally of the spacer.

Abstract: An enclosure for a loudspeaker is molded from a rigid acoustically inert material such as a polymer concrete. Preferably, the enclosure has an inner shell of a semi-rigid acoustically absorbent material providing damping for the enclosure. The enclosure may be conveniently manufactured by using a two-piece mold wherein the inner mold piece is sacrificed and forms the inner shell of the enclosure.

Abstract: An enclosure for a bass loudspeaker for housing in a larger multiple loudspeaker enclosure having a pair of concentric cylindrical shells filled with dense particulate matter.

Abstract: An improved loud speaker mounting frame having a continuous conic shape in cross section, so that by means of the conic and apertures along the apex on one side of the conic cross section shape the interference of negative sound waves within the cabinet is reduced and resonance problems of the cabinet are eliminated. Efficiency of the loud speaker system is thereby improved. The concept of conic formation includes an improved V-shaped filtering wave modulation plate utilized in small speaker cabinets.

Abstract: A speaker system which has a speaker unit with a diaphragm and an acoustic path provided on the front side of the diaphragm so as to guide sound waves emitted from the diaphragm. The acoustic path is defined by a sound absorbing member. The space in the acoustic path and the sound absorbing member is separated by a partition member which is disposed in such a manner that at least a portion of the sound absorbing member is exposed to the space in the acoustic path, except that the portion of the sound absorbing member just adjacent the diaphragm is not exposed to the acoustic path. This arrangement eliminates peaks and troughs of resonance determined by the length of the acoustic path, so that flat sound pressure frequency characteristics can be obtained over a wide range up to high-pitch tone region.

Abstract: A speaker enclosure assembly is disclosed, which comprises an enclosure provided with a baffle plate, to which a speaker unit is attached, characterized in that the enclosure is provided with a bellows-like sound pressure buffer member.

Abstract: Going inwardly from the outside, the walls of the housing comprise a multi-ply slab, one or more layers of elastomer coating, a plate of amorphous bitumen, and acoustic screens constituted by substantially contiguous parallel tubes which are filled with a solid material which is in the divided state and highly compacted, e.g. sand, or particles of graphite, or grains of silica. In addition, the enclosures include one or more blocks behind the loudspeakers and made of cellular foam with channels passing therethrough parallel to the axes of the loudspeakers.

Abstract: One or more up-firing woofer loudspeakers (12 or 22) are mounted atop a truncated pyramidal enclosure (1 or 21). A down-firing tweeter (5 or 25) is aligned above the woofer. A sound-reflecting sphere (4 or 24) is disposed between the woofer and the tweeter. When the sphere is aligned there-between omni-directional sound is radiated in both horizontal and vertical planes. When the sphere is positioned to the rear, a medium to high frequency forward hemispherical pattern is obtained. This pattern is desirable when the loudspeaker structure is positioned against a wall. Duct ports (3) or a folded horn (20) within the enclosure enhance very low frequency sound.

Abstract: The efficiency of a loudspeaker housing is substantially increased by incorporating in the housing, in the form of a lining or stuffing, a quantity of goat's hair, preferably mohair.

Abstract: A parametric loudspeaker utilizes nonlinearity of air relative to ultrasonic waves for producing an audio frequency having super directivity, and to thus provide a limited listening area public address system subject to a large listening area by safeguarding listeners by the provision of a framework for intercepting powerful ultrasonic waves and an acoustic filter. The depth and energy consumption of the parametric loudspeaker are reduced by the use of a reflective plate. Arbitrary directivity is obtained by the provision of a mechanism to move an ultrasonic wave radiator or the reflective plate. The parametric loudspeaker and any other loudspeaker may be combined.

Abstract: A sound radiating loudspeaker and tubular enclosure combination wherein the tubular enclosure is either formed in a helical configuration or two or more straight tubular sections which interest each other at an angle. In either form the tube is capable of free standing on a supporting surface with a loudspeaker closing the upper end of the tube and angled generally toward a listening area. Also in either form, additional speakers enclosed in shorter tubes may be joined to the main tube with all speakers either in a common plane or in planes at a slight angle to one another.

Abstract: A sound system, for a band or the like, incorporates an anechoic enclosure which allows a performer to use the same desired speaker color under all performing conditions and which insulates the audience and other pick-up microphones from each sound-source's speaker and insulates the pickup microphone for each sound source from the ambient room sounds. According to the system, a sound source, such as a musical instrument, outputs a first sound signal which is amplified and fed to a speaker in an anechoic enclosure. In response to the speaker output, a microphone in the anechoic chamber outputs a second sound signal which is amplified and distributed to room speakers. In its exemplary embodiment, the anechoic enclosure comprises four laminated layers: an inner layer of rigid closed-cell foam surrounding a chamber; a layer of denser flexible, closed-cell foam; a second layer of rigid closed-cell foam; and an outer hard, rigid layer. The enclosure may be opened so that the speaker therein may be heard.

Abstract: For years efforts have been made to construct acoustically completely dead loudspeaker cabinets. Interest has of course been taken in a neutral reproduction of the signals transmitted to the loudspeaker system, without the acoustic image being changed by cabinet resonances or other irrelevant sources of noise. According to the invention one or several of the cabinet walls are constituted by a hollow body (2), into the interior of which a foamed plastic material mixed with grains of comparatively high specific gravity is injected. These grains are sound and vibration absorbing, so that the walls are practically without resonances, and the weight is simultaneously reduced.

Abstract: An ultrasonic rangefinder capable of detecting a distance between a vehicle and an object with high accuracy is shown. The measure of microphones for transmitting and receiving ultrasonic waves is chosen so that detour waves are restricted.

Abstract: An ultrasonic transducer assembly includes noise suppressing backing material for the transducer comprising a composite of a matrix material and particles of an attenuating soft material such as rubber, epoxy, and plastic. The particle size is preferably selected by sieving the particles through a sieve of grid size 30 to 80. In preferred embodiments the particles of attenuating soft material are filled with particles of heavy oxides, metal powders, or other density lowering fillers. The ratio of matrix material to filler particles determines mechanical strength and attenuation of the composite material. Attenuation coefficient and size of the filler particles determines the attenuation of the composite material.

Abstract: A hollow enclosure that suspends a bidirectional microphone element within, in such a fashion as to improve the unidirectional characteristics, of said bidirectional microphone.

Abstract: An ultrasonic rangefinder capable of detecting a distance between a vehicle and an object with high accuracy is shown. The measurements for microphones for transmitting and receiving ultrasonic waves are chosen so that detour waves are restricted.

Abstract: The invention presents a method for improving overall efficiency and quality in sound reproduction systems by providing a system which establishes positive phase control over the many and varied resonant characteristics encountered in the reproduction and presentation of audio energy. The apparatus embodying the present method primarily consists of speaker structures within which drivers such as conventional cone drivers are acoustically coupled to both air and to the materials from which the enclosure of the speaker structure is formed by optimizing existing atmospheric pressure differentials and induced audio vibration readily available within these structures. The coupling is obtained through the use of acoustical resonator structure placed within a speaker enclosure and through particular distribution of mass in the enclosure and in the materials.

Abstract: A pressure modifying device and method which utilizes a gas or vapor and an adsorbent material to reduce the amplitude of pressure variations in gas or vapor. The technique is applicable to loudspeaker assemblies having a box (2), low frequency loudspeaker (16) and a mass (20) of activated charcoal in the box. Excursions of the cone (18) of the loudspeaker in the range 20 to 100 Hz cause pressure fluctuations in the air in the box but the size of those pressure fluctuations is comparatively small owing to increased air adsorption on the activated charcoal leading to increased efficiency.

Abstract: The invention relates to a loudspeaker box designed as a shell construction, where the outer and inner peripheral surfaces of the box are made of reinforced plastic and are preferably twin-curved with a continuously varying radius of curvature, where the distance between the outer and the inner shell is not constant and where the space between the shells is filled with a light material with good adhesion to the shells, preferably foam plastic. This design principle is intended to avoid natural resonances while at the same time ensuring low weight and high strength.

Abstract: This invention relates to low-frequency speaker enclosures in general, and more specifically to dual cabinet construction, wherein each of the cabinet structures contains a portion of a pre-formed generally semi-circular variable diameter horn passageway, surrounded by contoured foam elements that provide sound insulation for the horn passageway wherein the pre-formed horn passageway produces redirection and amplification of rear-cone sound wave energy, through the forward face of the combined cabinet construction.

Abstract: A multi-chamber loudspeaker enclosure comprises a primary chamber having a principle interior volume and a secondary chamber having a minor interior volume substantially smaller than the principal interior volume. The secondary chamber comprises an elongated housing mounted to a front wall of the primary chamber. The secondary chamber has a speaker mounting opening from the enclosure and an interior opening that opens simply and directly from the secondary chamber into the primary chamber. The two openings are substantially coaxially aligned. The speaker mounting opening is the only opening from the inside of the enclosure to its exterior. The secondary chamber projects from one of the faces of the front wall of the primary chamber. The length of the secondary chamber between the two openings is substantially greater than the length of a loudspeaker mountable in the speaker mounting opening. This multichamber loudspeaker enclosure has enhanced freedom from resonance.

Abstract: This portable sound speaker system has an elongated cylinder supporting a layer of acoustically absorbent material lining the interior surface thereof. The cylinder has an open, raised platform as its support in a vertical position, where the platform has a first base plate carrying a plurality of spacers on which is fastened a second plate having a large central hole open to the interior of the cylinder to allow the bass sound to radiate radially outward therefrom. A first, low frequency loudspeaker is fitted down into the upper end of the cylinder, and it radiates upwardly. A second, high frequency loudspeaker is mounted above the first loudspeaker, and it radiates in a generally horizontal direction. A cylindrical speaker grille is fitted over the second loudspeaker and mounted to the top end of the cylinder.

Abstract: A high mass speaker enclosure having a speaker mounted to a front escutcheon plate and below which a multi-gated balanced acoustical transmission yoke is mounted and whereby a portion of the enclosure's interior air pressure is relieved so as to augment the speaker sound, especially at frequencies below 60 hertz. Enclosure resonance is minimized via the use of a high mass enclosure and the filing thereof with a fiberglass material around the speaker and a Dacron filler around the transmission yoke, while front mounted polyester mats preload the speaker and transmission yoke. Speaker resonance, lost sounds and/or extraneous speaker induced sounds are thereby avoided.

Abstract: A motion picture loudspeaker system is described in which the loudspeaker elements are integral with an acoustical boundary wall such that the characteristics of the vented box woofers are optimized. In order to overcome high reflection problems as sound from the tweeters is reflected by the motion picture screen and the acoustical boundary wall, frequency dependent acoustical absorptive material is attached to the wall to inhibit high frequency reflections with minimal effect on the bass optimization. The system includes the use of a steep slope crossover netowrk having a crossover frequency such that there is a first order match of the woofer and tweeter dispersion at the crossover.

Abstract: A gas-filled damping element for damping pressure pulsations, especially in an internal chamber of a pumping unit for pumping liquid fuel from a fuel storage receptacle to an internal combustion engine includes a rigid support member of a substantially plate-shaped or cup-shaped configuration, and a diaphragm having a marginal portion which is sealingly secured to a border zone or rim of the support member. The surface area of the diaphragm is greater than the projected area of the support member. The enclosed space between the rigid support member and the diaphragm is filled with a gaseous medium. A support element or portion extends into the enclosed space between the diaphragm and the support member, this support element having an abutment surface of an area smaller than the projected area of the support member and facing the diaphragm. The abutment surface serves for supporting the diaphragm when the damping element is exposed to extremely high pressures.

Abstract: The invention provides an enclosure arrangement or a loudspeaker adapted to be mounted in a voice communication terminal. The invention provides primary and secondary enclosures for the loudspeaker. The primary enclosure comprises a piece of resilient open cell foam material having one face provided with a concavity suitable for receiving the spider and the voice coil structure of the loudspeaker. The peripheral edge of the one face of the foam material is secured to the peripheral edge of the spider and the outer surface of the foam material has a flexible layer of substantially air-impermeable material, whereby the loudspeaker is provided with an attached flexible enclosure. The secondary enclosure comprises the housing in which the loudspeaker is mounted. The flexibility of the primary enclosure allows energy to be coupled between itself and the secondary enclosure.

Abstract: A loudspeaker is provided for high-quality and particularly stereophonic sound reproducing systems positioned close to a wall of a room. To reduce distortion due to that part of the reflected sound which arrives from substantially the same direction as the direct sound, the positioning of the sound radiating surfaces is such as to make the reflected sound from the wall arrive substantially in phase with the direct sound throughout a large frequency range, while at higher frequencies the reflected sound is attenuated by a sound absorber.The loudspeaker has a casing with a rear wall (5a). Loudspeaker units arranged to be the sound source for mid-range (12b) and/or high (14a) frequencies has the sound radiating surfaces (12b, 15a) at short distance (D2, D1) from the plane of the rear wall (5a) and facing slantwise forwards.

Abstract: An enclosure for a loudspeaker has a housing formed of sound reflecting material having opening dimensioned for mounting of a loudspeaker therein. A body of sound deadening material is disposed within the housing. The body of sound deadening material defines a bell-shaped chamber having a top and a bottom. The top of the bell-shaped chamber is located at the loudspeaker opening and the bottom of the bell-shaped enclosure is remote from the loudspeaker opening. The enclosure is preferably used in combination with a novel sinusoidal waveform energy reflector. The reflector has first and second surfaces each having an exponential cross-section and being reflective to the waveform energy. The first surface terminates in an apex pointing at a source of the waveform energy, such as a loudspeaker. The second surface intersects the first surface around a perimeter of the first surface.

Abstract: A passive system having high volumetric compliance in response to compressions and expansions, such as are present in low frequency acoustic wave energy, employs a saturated vapor-saturated liquid interface thermodynamically stabilized by distributed heat sinks that interact with the acoustic wave energy. The volumetric compliance of a system, such as a loudspeaker enclosure, is significantly increased by utilizing a spatially distributed mass of fine fibers thoroughly wetted by a liquid, to provide thin liquid sheaths on the fibers that are in good thermal interchange with the fibers themselves and also with the vapor molecules in the spaces between the fibers. The liquid preferably has a low heat of vaporization, a high vapor pressure at the ambient temperature and a low rate of pressure change with respect to temperature. The liquid sheaths and fibers serve as high surface area heat sinks having a short thermal transport distance to supply the alternating heat attendant to evaporation and condensation.

Abstract: The acoustical energy absorbing baffle has a pair of restricted orifice screens rigidly secured in parallel, spaced relation by a lattice stiffener. The screen-stiffener assembly is immersed in a viscous fluid contained within a tank sealed with an elastic diaphragm. Incident acoustical energy is transmitted through the diaphragm and translated into energy absorbing motion of the fluid through the restrictive screens. A compliant mass is acoustically coupled to the fluid to augment fluid particle velocity through the screens and to further absorb energy.

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: A loudspeaker enclosure has a loudspeaker driver mounted on a surface of the enclosure such that the driver has an exposed front face to produce sound waves which are sought to be transmitted to a listening space exterior of the loudspeaker enclosure. A plurality of successive spaced limp or semi-limp non-porous pliable barriers are positioned in an opening between the interior and exterior spaces of the enclosure so as to relieve rear pressure of the loudspeaker driver while attenuating the rear sound waves and providing a damping effect on the loudspeaker driver.

Abstract: A controlled dispersion loudspeaker configuration is disclosed in which a loudspeaker is mounted through a hole in a front baffle forming a seal between the speaker and the baffle. A rear baffle is parallely spaced a predetermined distance away from the front baffle by means of spacers. Acoustically absorptive material is placed between the two baffles and is acoustically open on at least two opposite sides. The sound waves from the rear of the speaker exit from the acoustic material and serve to cancel the sound waves at the sides and rear of the loudspeaker configuration eminating from the front of the speaker. The size of the baffles, as well as the spacing therebetween, bears a particular relationship to the frequency of the sound to be reproduced by the loudspeaker.

Abstract: The invention relates to a housing loudspeaker which in addition to the loudspeaker opening has a further opening in its outer wall of the housing. Components are provided in the inner space between the loudspeaker and the opening which should eliminate the sound emitted into the inside by the loudspeaker. For a surprising effective elimination of the sound and a corresponding capacity increase of the loudspeaker a consistent filling of a cross sectional face in the box intermediary space is provided which is composed of two partial faces with mutual components of different functions. One of the partial faces is designed as a large face and consists of a flow tight finishing of an elastically vibrating braced mass, for which a plate combination is used in particular. The other partial face is designed of a smaller face and consists of a flow opening which, however, is closed with a layer of granulated or transversely directed thread like material.

Abstract: A loudspeaker system is provided wherein sound absorptive foam material is affixed to the sides of the loudspeaker cabinet so as to absorb that portion of the sound radiated from the loudspeaker that is directed towards the rear of the loudspeaker system, thereby serving in eliminating sound reflections from the walls of the room. This results in an overall system which can more accurately reproduce the recording site ambience inherent in a recording and which permits more accurate and natural imaging, i.e., more precise localization of voice and instrument placement within the soundfield of a pair of stereo loudspeakers.

Abstract: There is disclosed a method for making horn loudspeakers, of the sectorial diffusion type, characterized by the transformation, in order to operate under predetermined sectorial diffusion conditions, of a horn loudspeaker, predisposed for circular diffusion, comprising a horn provided with opposite walls the distances whereof increase according to a given law, from the axis of the horn on which the electroacoustic transducer is located, the transformation being carried out by neutralizing the space included between the walls and about the compression chamber associated with the transducer, and in the directions in which the diffusion is not desired, by using a substantially fibrous material and effective to absorb or deaden the acoustic energy or power.

Abstract: A unidirectional dynamic microphone provided with a first sound path to the forward side of the diaphragm and a second sound path to the rear side of the diaphragm in which the second sound path has a chamber coupled to a second chamber associated with the diaphragm through a distributed acoustic RC damping assembly.

Abstract: A ribbon loudspeaker is suitable for incorporation into a sound reproduction system without additionally requiring a transformer or series resistor. In one form in which the loudspeaker is bi-directional, a sound reproduction ribbon is received in a pair of magnetic gaps formed from a magnetic system employing a single magnet.

Abstract: An electrical acoustical transducer is provided having a piezoelectrical layer in a housing with a transducer plate. The transducer plate divides the housing into a front chamber and a rear chamber. In the rear chamber, there is provided a Helmholtz resonator for the attenuation of resonance increases. With the invention a Helmholtz resonator is designed such that its acoustical characteristics do not change through environmental influences. Instead of covering the resonator by means of a customary silk disk, several narrow slots are arranged in the carrier plate.

Abstract: The invention concerns an electro-acoustical transducer with a transducer plate having a piezo electric layer and which subdivides the housing of the transducer into a front and back chamber. In the front chamber, means are provided for the attenuation of resonance increases comprising Helmholtz resonators and an attenuation disc. According to the invention, the Helmholtz resonators are designed in such a manner that their effective surface is not reduced in size by means of the attenuation disc or wafer. This is attained according to the invention in that slots are formed in a separating plate.

Abstract: Both an improved loudspeaker enclosure and an improved acoustical process for generating sound radiation in a room is herein disclosed. Basically, the walls of the improved enclosure include a loudspeaker, and a sound transmission port for transmitting sound generated by the back of the loudspeaker cone into the room. The interior of the enclosure includes a tuned acoustical chamber for absorbing the even and odd harmonics of the system resonance frequency, and a compression chamber acoustically coupled at one end to the back of the loudspeaker cone. The compression chamber is acoustically coupled to both the tuned acoustical chamber and the transmission port of the enclosure walls by means of an acoustical coupling.

Abstract: The present invention is a device for use in combination with a loudspeaker system, that includes a speaker enclosure, in order to effectively enlarge the volume of the speaker enclosure thereby increasing the apparent compliance of the speaker enclosure. The loudspeaker system also includes a vibratable cone. The device may also permit the varying of the mass of the moving system with respect to frequency. The device for effectively enlarging the volume of the speaker enclosure includes a gas having a Joule-Thomson coefficient of less than zero above its inversion temperature, and an inversion temperature below the ambient temperature of the environment in which the device is to be used.

Abstract: An improved, compact speaker system for production of the full range of sound audible to the human ear, the sound radiating from the speaker being omnidirectional with the speaker including an outer cabinet shell and a defined chamber configuration within the shell. High and low frequency speakers are mounted within the cabinet shell with an acoustical path being defined within the cabinet for the low frequency wavelengths with the low frequency tones traveling within the cabinet for a distance of 1/12 the wavelength of the natural free air resonance of the low frequency speaker. The high frequency speaker having a slug of pre-determined surface configuration to permit omnidirectional sound radiation without distortion.

Abstract: An improved loudspeaker housing including a closed chamber in the shape of a triangular right prism closed at both ends. All of the three walls of the prism and rectangular in shape and two of the walls are at right angles to each other. A circular opening in a first of the two walls adjacent the right angle is provided for a loudspeaker which is attached to the outside of the first wall with the sound output of the speaker directed against the third, or hypotenuse, wall of the prism. An opening is provided in the third wall which is in the shape of an exponentially widening gap. A box is placed over the outside of the first wall enclosing the loudspeaker, and is lined inside with sound absorbing material.

Abstract: An improved speaker mounting for an electronic guitar is provided. The mounting includes a rubber cup extending into the interior of the guitar from a cut out in the top board surface of the guitar. The cup has a flanged rim extending about the opening and a grove formed below the flange. A speaker is disposed within the cup and has portions captured in position by the grove. A cap is positioned over the cut out and screw means extend through the cap and cup flange into the guitar top surface securing the cap and flange to the top surface.

Abstract: A speaker enclosure comprising a cabinet that defines an upper compartment and a lower compartment. A sectorial horn is mounted in the upper compartment and a prismatic member is disposed across the outlet of the horn to direct the sound energy upwardly and downwardly from the horn. Mounted in the lower compartment is a full range speaker which is spaced from the sides of the cabinet to provide side openings. Positioned behind the speaker is a W-shaped baffle which serves to deflect the sound energy emitted from the rear of the speaker outwardly through the side openings.

Abstract: A loudspeaker system makes use of a closed cubic enclosure the front of which is a square baffle having tapered edges, the intersections of which fit the outline of an imaginary sphere which substantially encompasses the enclosure. Wide dispersion of audible acoustic waves of low frequency with a minimal amount of diffraction from a woofer loudspeaker mounted in the baffle at the convergence of the tapered edges occurs. A tweeter is mounted in substantially freely spaced relationship with the enclosure to provide also for wide dispersion of acoustic waves of high frequency. The enclosure is tuned to enhance the low end of its frequency response. A semirigid foam front panel having beveled edges is disposed on the baffle over the woofer and acts as an acoustically transparent front grill for the system. The tweeter is encased in acoustically transparent material mounted on the top of the enclosure.

Abstract: A loudspeaker enclosure of the acoustic suspension type has a hollow interior of a generally spherical shape, and the enclosure is formed of polyurethane foamed plastic in which the volume (V) of the enclosure interior is determined according to the following empirical formula:V=[MD].sup.3where M is the distance between the limits of mechanical excursion of a given loudspeaker mounted in an aperture in the enclosure as the diaphragm of the speaker is moved under a constant mechanical force, and D is the diameter of the loudspeaker.

Abstract: A loudspeaker enclosure comprises a housing defining therein a principal volume having a front wall and a substantially smaller minor volume. The minor volume has a rear wall common to the front wall of the principal volume. The common wall defines a port which communicates the minor volume to the principal volume. A speaker mounting opening is defined in a front wall of the minor volume. The speaker mounting opening defines the only opening from the exterior of the housing to the interior thereof.