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 electro-acoustic transducer is formed of a loudspeaker enclosure having a form of revolution about an axis each end of which is closed by a loudspeaker. The two loudspeakers are mounted back to back in the axis of the enclosure, one of the loudspeakers being fed from an electric power source and being in this sense "active", whereas the other loudspeaker is "passive" in that it receives no electric supply, its movements resulting from the rear wave of the active loudspeaker. The enclosure is maintained vertically along its axis of revolution, and, on the other hand, the side wall of the enclosure is formed of a flexible material, unlikely to resonate with the front and rear waves of the loudspeakers.

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: 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: A speaker transducer assembly is disclosed which includes first and second speaker diaphragms supported on a frame in over and under juxtaposition. Each of the speaker diaphragms has a central opening defining an inner periphery which is attached to a voice coil form for coaxial movement therewith and in unison. An intermediate baffle is coaxially positioned between the speaker diaphragms to define upper and lower, separately vented chambers. The upper chamber is vented through an outlet in the region of the outer peripheries of the first speaker diaphragm and the intermediate baffle; similarly, the lower chamber is vented through an outlet situated in the region of the outer peripheries of the second speaker diaphragm and the intermediate baffle. Preferably, the two vent systems have different vent exhaust areas to obtain stagger tuning and thus achieve a split of the deepest frequency load.

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 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: A speaker system comprises a housing and at least one speaker mounted in said housing. An acoustical filter for intercepting and reradiating sound waves is mounted in front of the cone of the speaker. The acoustical filter includes a frame having a central aperture and at least one membrane mounted to the frame covering the aperture and having a resonant frequency of vibration. A plurality of slots are formed in the frame adjacent the aperture. A dispersion grid for increasing the spacial angular dispersion of sound waves generated by the speaker is mounted in front of the frame.

Abstract: A loudspeaker enclosure comprises a rectangular box-like housing (100) consisting of top (102) and bottom walls (104), front and back walls (106), left (108) and right (110) side walls, each of the walls being formed by a wooden panel, a hollow stiffening structure (200) located within the housing (100) and extending from the top wall (102) to the bottom wall (104), from the front wall to the back wall (106), and from the left side wall (108) to the right side wall (110), the hollow stiffening structure (200) comprising a first set of spaced-apart stiffening panels (1,2,3) arranged with their planes substantially parallel to each other and substantially parallel to the walls of a pair (102, 104) of opposed housing walls, and a second set of spaced-apart stiffening panels (4,5) arranged with their planes substantially parallel to each other and substantially parallel to the walls of a different pair (108, 110) of opposed housing walls, the stiffening panels (1,2,3) of the first set being secured to stiffening

Abstract: A resin-molded wall-mounted speaker cabinet which has a reduced thickness and weight. The four side walls of the cabinet are inclined inwardly towards the back of the cabinet, and a terminal plate is mounted on one of the side walls. A baffle board is fitted into a front opening in the body of the cabinet, and a tweeter and a woofer are mounted in the baffle board. The tweeter and woofer are covered by a grille board and front grille. Adjacent the tweeter and woofer on the front surface of the baffle board is mounted a rigid plate, separated from the baffle board by a sound absorbing layer. The rigid plate may be made of glass, and a picture or the like may be placed behind the glass.

Abstract: A headrest hollow casing has a central vented chamber connecting end chambers in which stereophonic loudspeakers are mounted and such central chamber is loosely filled with batting or other sound-damping material. The casing is supported by mounting rods or mounting bar angularly adjustable relative to the casing.

Abstract: A loudspeaker enclosure is arranged to support an electromagnetic loudspeaker of the type having both front and back acoustic waves, with the front of the speaker registering with a front wave opening in the enclosure and the back of the speaker communicating through a transmission line cavity with a port the plane of which is disposed substantially normal to the plane of the front wave opening and which port is provided with a cross sectional area of about 0.5 to about 2.0 times the operative area of the driver cone of the loudspeaker, thereby giving a highly efficient means of sound propagation. The enclosure may also house high frequency "tweeter" speakers which provide only a front wave. Acoustic murals and other type reflectors and deflectors may be associated with one or more of the enclosures in an assembly within a room to give the illusion of sound emanating from many more sources than there are loudspeaker enclosures.

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 loudspeaker assembly for use outdoors is disclosed. A woofer speaker is secured in a housing for the downward projection of sound through a generally continuous circumferential aperture between the housing and base. A tweeter is mounted coaxially with the woofer for the projection of sound downwardly thereby providing for the omnidirectional projection of sound from the speaker assembly.

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 ported speaker enclosure is disclosed for extending the low-frequency range of the enclosure and increasing the intensity of the low-frequency range of reproduced sound wherein the size of the enclosure, the locations of the speakers, and the size and locations of the ducted ports are determined by relatively simple relationships based solely on speaker cone dimensions. In one form, a ducted port speaker enclosure is comprised of two bass-range speakers, or woofers, wherein one woofer is located in a predetermined position above the other on the enclosure. An open sector of a plurality of open sectors of the frame at the back of the topmost speaker faces towards the top and an opposite open sector faces towards the bottom of the enclosure of the two woofer system. A sound damping material is added to cover the top and bottom facing sectors of the topmost speaker. Insulation material of predetermined dimensions is affixed to the inside walls of the right and left sides of the 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: 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: A loudspeaker apparatus is provided for producing time and phase-coherent sound waves, substantially hemispherical in shape, directed toward a listening area. The loudspeaker apparatus includes a simply-constructed, inverted speaker cone designed to produce primarily low and medium frequencies, a high frequency speaker uniquely positioned above and behind the axis of the cone to supplement the high frequencies, and absorbing material disposed inter alia at a rear portion and at the smaller end of the cone to produce the hemispherical-shaped sound waves and direct them toward the listening area.

Abstract: A speaker enclosure having a rear bass-reflex chamber and a forward mid-range chamber formed within a substantially rectangular housing. A tunnel-bass port is formed in the bottom section of the front wall of the enclosure, the bottom section being angularly disposed and arranged to communicate with the rear bass-reflex chamber. The upper section of the front wall is provided with a mid-range port that communicates with a mid-range chamber. A bass speaker is mounted to a central partition which divides and separates the bass and mid-range chambers. A sealed, self-contained, mid-range speaker is also mounted to the central partition and arranged to disperse mid-range tones by way of the mid-range chamber, so as to exit the mid-range port in unison with the high-frequency tones produced by a tweeter mounted to the upper front wall section. Thus, each speaker disperses its own frequency range in a clear and distinct manner.

Abstract: An acoustic reproducing apparatus is provided which includes first and second channels and first and second speakers, all disposed in a housing with a sound path for acoustically coupling the first and second speakers. The sound path has disposed therein sound absorbing material which forms a low pass filter which operates to add the low frequency signal component of the first channel to the second channel and also operates to add the low frequency signal component of the second channel to the first channel to produce a composite low frequency signal with greater amplitude which is reproduced in phase by each of the first and second speakers.

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: High quality stereo sound dispersion is obtained through the use of a speaker cabinet having three tiers of speakers which are effectively sound insulated from one another. The topmost and bottommost tiers have speakers which are oriented in divergent directions from one another, while the intermediate tier has speakers which are unidirectionally oriented. Horizontal sound panels are provided between the respective tiers of speakers to accomplish the sound insulating effect, and the speakers themselves are mounted in vertical panels which form walls associated with sound compartments. In this respect, the divergently oriented speakers are positioned within walls of triangularly shaped sound compartments, while the unidirectionally oriented speakers are contained within a wall of a rectangularly shaped sound compartment. The respective sound compartments are sealed airtight and are filled with acoustical fiber glass to create the desired sound enhancement characteristics.

Abstract: A speaker system includes a housing with four side panels and a back panel. A speaker mounting panel with a plurality of openings therethrough is positioned opposite the back panel to enclose the housing and define an acoustic chamber therein. A packed fibrous sheet material is attached to cover the interior surfaces of the side and back panels. A pair of unmatched drivers and a tweeter are mounted to the mounting panel so that each projects frontwave sound through one of the panel openings and backwave sound into the acoustic chamber. An open-ended cylindrical member defining an acoustic passageway is attached about the periphery of another mounting panel opening and extends part way into the acoustic chamber. An acoustic curtain extends between opposite side panels in a serpentine configuration about a portion of the periphery of the two drivers on one side of the curtain and the periphery of the cylindrical member on the other side of the curtain.

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: Disclosed herein is a sound diffusion plant with very low directivity. The plant, normally of the multiway type, is essentially characterized by the fact that each way comprises a pair of loudspeakers arranged one opposite the other, the diaphragms of which are enclosed in a space delimitated by screening elements made of high acoustic absorption material.The said plant enables the sound diffusion to be uniform in the surrounding space and makes it possible to limit greatly undesired effects, such as for example, sound "haloes" and identical sounds reproduced by different ways being out of phase.

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 enclosure for use in housing loudspeakers, the loudspeaker enclosure comprising a casement having a generally rectangular cuboid shape, the casement including three layers. A first layer and a second layer comprise sheets of metal and are space apart to provide for an inner layer of plastic material. In one embodiment of the invention, the casement is formed by bending a sheet of material including the three aforementioned layers to conform to a generally rectangular cuboid shape. In another embodiment of the invention, the first layer of metal is bent to a rectangular cuboid shape defining four interior surfaces. A flat layer of plastic and a flat layer of metal is applied to each interior surface of the casement. The casement provides a wall having a relatively high density, a high modulus of elasticity and a high damping factor.

Abstract: A loud speaker and enclosure system that has improved acoustical properties, comprises a cubical frame composed of two sidewalls, a top and a bottom, having an open front and back. The frame is made of substantially rigid material. The backwall is closed by means of a panel of styro-foam. An acoustical horn in the form of a truncated square pyramid is molded from foamed plastic and is of such size as to be fitted into the inner space of the frame with the wide end of the pyramid at the front end of the frame. Means are provided at the corners of the pyramid, for attachment to the frame. Along the walls of the horn there is a space between the walls of the horn and the walls of the frame, of selected dimension. At the small end of the horn is a transverse wall, which has a circular opening. A low frequency, large diameter, cone type speaker is fastened to this wall, mounted inside of the horn, with the cone facing toward the back of the frame.

Abstract: A speaker system comprises an enclosure and at least one speaker mounted therein. The enclosure includes at least one duct connecting the interior of the enclosure directly with the outer air at the front thereof. Each duct is confined at least at one side by a member extending substantially normal to and running substantially the width of the front of the enclosure. The member has its front and/or rear edge rounded so that the cross-sectional dimension of the opening of the duct at the respective edge is greater than that of the central section of the duct.

Abstract: A speaker assembly comprising a first cabinet or housing of a pyramidal configuration having a speaker element mounted therein in such a manner that the sound emitting from the speaker is concentrated in a direction outwardly of the pyramid, and a second housing of pyramidal configuration disposed in spaced relation to the speaker element whereby the sound emitting therefrom is directed against the walls of the second pyramid to provide a complete sound emission from the assembly through three hundred and sixty degrees.

Abstract: A speaker system in which at least one driver is mounted on an enclosure and is adapted to radiate sound waves outwardly from said enclosure in response to an input signal. A sound absorbing material is disposed on at least a portion of the outer surface area of said enclosure to reduce the effect of diffractions and reflections of said sound waves relative to said enclosure.

Abstract: A multiple driver loudspeaker system comprises two angularly spaced rear rectangular baffles each nearly filled with four closely spaced full-range small loudspeakers with a port tube passing through the center of each rear baffle and the junction therebetween. A front baffle carries a small centrally located loudspeaker. The front loudspeaker is backed by a cavity that is vented through the port tube at the intersection between the rear baffles. Each of the remaining loudspeakers is backed by a cavity with the four cavities associated with each rear baffle being vented through the associated port tube through channels located at the front of each cavity. Two bullets are cantilevered from the front baffle rearward and essentially concentric within the respective centrally located ports. The volume of each of the nine cavities is substantially the same.

Abstract: A loudspeaker system for the passenger compartment of a vehicle, such as an automobile, is disclosed. The system has at least two loudspeakers arranged on opposite sides of the passenger compartment in the end regions of a rigid, hollow support element which is closed on all sides and extends across substantially the entire width of the passenger compartment. This hollow support element is at least partially filled with sound absorbing material.

Abstract: A loudspeaker system which has a frequency response at any angle located about the speaker system which will be uniform such that the output sound pressure at any frequency from the speaker system will be as great or greater than the sound pressure from any other direction which comprises a reflected path from the speaker system. The speaker system includes a radial horn which radiates a spherical sector rotated 360.degree. through a horizontal plane is provided. One or two speakers are mounted so that they produce a pulsating cylindrical wave which feeds into the radiator and an inverted conical member is mounted in the transition portion between the pulsating cylinder and the output horn portion. This output is blended with similar wavefronts produced by a low fequency loudspeaker which is acoustically associated with a vented box. The vent is on the periphery of the box adjacent the low frequency loudspeaker and is narrower than the thickness of the walls of the box.

Abstract: A loudspeaker having precise imaging, neutrality of frequency response, and controlled mid-range and tweeter dispersion. The loudspeaker incorporates an open cell, reticulated polyurethane cartridge for placement of a supertweeter mounted in the loudspeaker at an angle of 45.degree. from other speaker axes. The housing therefore may be positioned so as to adjust the high frequency acoustic radiation to the right or the left of the loudspeaker frontal axis, thus making a mirror image pair of the loudspeakers possible. In addition, angled corner posts are arranged at the front corners of the loudspeaker in order to reflect back into the loudspeaker mid-range and high frequency sounds that strike the posts.

Abstract: A compact loudspeaker system adapted for the reproduction of sound at minimum distortion. Two small diameter direct radiator loudspeakers and a matching crossover network are mounted in a common enclosure having a short non-folded transmission line completely filled with randomly oriented non-woven fibers, said fibers having a single installed density within range of 12 to 30 ounces per cubic foot. The first of these speakers, a bass/mid range unit is acoustically coupled to one end of the fiber filled transmission line by exposing the speaker radiator rear surface to the line while the second speaker, a high frequency unit, is acoustically isolated from the transmission line by encapsulating the speaker radiator rear surface in a housing integral with the second speaker. A port, located at the end of the transmission line, acoustically couples said line to the atmosphere.

Abstract: The rear cavity of a tweeter speaker includes a cylindrical block four of a rigid, open celled, homogenous foamed material, such as aluminum. The rear end of the cylinder is cut to expose open cells, and is coated with an impermeable resin film, whereby the block absorbs and dampens back-pressure vibrations within the speaker cabinet from the low frequency woofer, and reduces standing and reflected waves generated by the tweeter. Alternatively, the entire block may be enclosed within a case five.

Abstract: A loudspeaker cabinet system wherein at least two low frequency drivers of equal effective diameters are critically spaced a vertical distance which equals the effective piston diameter of one driver times .pi.. When so placed, the respective spherical wave fronts of the drivers interfere causing a composite elliptical wave front which being flatter than the spheric can reflect from walls without drastically changing its shape to produce a uniform field which reaches the listener without producing any areas of the room which appear acoustically dead. Such system is especially useful in small rooms having reflective wall surfaces. Once the low frequency drivers are critically spaced and aligned, a higher frequency speaker or array of higher frequency speakers can be positioned thereabout without destroying the quality thereof.

Abstract: A high fidelity loudspeaker system involving a multidriver, semi-omnidirectional, full range, electrodynamic loudspeaker including two, separate but complementary, closed box-like enclosures, an upper unit containing an array of mid-range speakers around three sides and a lower unit containing arrays of low and high frequency speakers around three sides. The low frequency speakers (woofers) on their interior sides include a series of tubes opening into the closed interior of the speaker enclosure, having various lengths in accordance with certain relative, locational relationships. Although the low and high frequency speakers include a single crossover frequency circuit, the "mid-range" speakers are not included in any crossover network but are driven throughout the total frequency input range, although a capacitor can be included to cut off the very low frequencies to the mid-range speakers.

Abstract: A bass unit for a loudspeaker system which has a pair of loudspeakers mounted one behind the other in a casing to define a chamber of air therebetween. The loudspeakers are operated in phase with one another so that the pressure of air in the chamber remains substantially constant and the loudspeaker which is mounted on a front wall of the cabinet thus operates under substantially "ideal" conditions. Any changes in sound pressure within the chamber represent distortion components and are absorbed by a curtain of absorbent material in the chamber by a filling of absorbent material.

Abstract: A damping element comprising fiberous fuseable material shaped to form a cup-like member which may be inserted in the sound openings of an acoustic transducer to provide a selected acoustic resistance.