Abstract: This invention describes two products both with a plain, fine textured, nonperforated surface visual consisting of a fiberboard substrate with or without a laminated porous nonwoven scrim and then a finished painted surface. The finish painted surface decorates or finishes the board, but most important, must remain acoustically transparent to retain the sound absorption properties of the fiberboard prior to painting. The fiberboard substrate is made to be porous or modified with hole perforations to cause it to be a good sound absorber. If the fiberboard substrate is sufficiently porous without hole perforations, then the sprayable, high solids, porous paint can be directly applied. If hole perforations are used to improve the sound absorption properties of the board substrate, then a porous, nonwoven scrim is attached and painted using the same high solids porous paint.

Abstract: By means of this acoustic protection it is possible to protect the payloads of expandable launch vehicles effectively against noise emissions from the rocket propulsion system which result in damage of the payloads. For this purpose acoustic absorbers (8) tuned to a defined frequency range are provided and are arranged in foamed plastic mats (7) disposed on the insides (6) of the payload fairing (1). The acoustic absorbers (8) are composed of a cup-shaped lower part (12) and an upper part (13) having a horn (18). The horn (8) tapers in a curved-conical manner from a larger diameter (D.sub.m) to a smaller diameter (D.sub.t) and projects into the lower part (12) by a defined distance (a) from a bottom (14) thereof. Slits (21) for the dissipation of the directed flow energy occurring in the horn (18) are disposed in the wall of the horn in the area of the smaller diameter (D.sub.t).

Abstract: Numerous embodiments of a nestable sound absorbing foam each including a reduced area of attachment to an adjacent wall surface and a variable depth air cavity to enhance absorption. The embodiments include various configurations of "one-dimensional" sine waves, saw tooth cross-sections, triangular and crown shaped cross-sections as well as square wave cross-sections and part cylindrical cross-sections. In addition, two-dimensional nested topologies with a variable depth air cavity are also described. In each embodiment, the major portion of the rear surface of the material which is to be attached to a wall surface is spaced as far as possible from the wall surface creating a variable depth air cavity to enhance sound absorption. When the rear air cavity is sealed, additional low frequency absorption is achieved by increased air flows through the foam material caused by the pressure gradient in the low frequency pressure zone.

Abstract: A sandwich plate has a pair of relatively dense, stiff, thin, and generally parallel longitudinally extending skins, and a less dense core body having a pair of generally parallel faces bonded to the skins and formed with longitudinal and transverse cavities connected together in a Z-shape and forming central longitudinally extending tongues.

Abstract: A panel for an office sound screen includes a core which includes an asphalt layer and insulation layers positioned on both sides of the asphalt layer. Preferably the asphalt layer has a thickness between 0.030 inch (0.076 cm) and 0.125 inch (0.318 cm). The asphalt layer acts as an adhesive so that the insulation layers are laminated thereto. Preferably the insulation layers are made from a fibrous glass wool insulating material having a density between 0.5 pounds per cubic foot (8 kg/m.sup.3) and 5 pounds per cubic foot (80 kg/m.sup.3). The panel further includes a cover layer positioned on at least one side of the core.

Abstract: A sound insulating barrier for improving acoustics in buildings, theaters, and around freeways, is disclosed. The sound insulating barrier has a multi-layer construction made of a layer of wood wool, a layer of basalt insulation material, a layer of sheet rock and a central core of basalt insulation material. These layers are repeated on the opposite side of the central core of basalt insulation to obtain a stand-alone wall. Alternatively, the layers up to the central basalt insulation layer can be attached to any pre-existing flat surface. The basalt insulation material is made of mineral wool. Conventional spacers can be used to separate layers or to improve the integrity of the wall. Furthermore, the sound insulating barrier can be built around conventional construction studs.

Abstract: A molded article for the absorption of airborne sound, to be used principally in the engine compartment of motor vehicles and particularly as a sound absorber inside partial and complete motor encapsulations, is formed by a porous absorber (1) of which the core (6), being sealed on both sides (7,8) over its complete surface by a respective PU film of a thickness less than 90 .mu.m, is made from an open-pored PU (polyurethane) foam of a thickness of at least 3 mm and about 15 mm at the most. The core comprises cavities (2-4) originating on the bottom face and formed by the injection molding process, said cavities being open only towards the bottom face (5) and having different cavity volumes and different heights (11) measured from the bottom face (5).

Abstract: An engine compartment casing element (1), in particular for sound absorption, with a foamed material element (2) attached to a wall element (3) which is preferably reverberant, the foamed material element (2) having a skin-like covering (5) on the side facing away from the wall element (3). The foamed material element (2) is perforated, the foamed material element (2) is also covered on both sides with an air-impermeable plastic sheeting (5) or (6) respectively which also covers the perforated areas (holes 4), and the foamed material element (2) is installed so that it runs at least in part at a distance (a) from the wall element (3).

Abstract: A moisture-permeable acoustic lamina which is usable as a wall covering has a foraminous woven fabric layer adhered to a fabric backing by a discontinuous thermoplastic polymer layer. The woven fabric preferably has an embossed undulate outer surface to enhance the acoustic properties of the lamina and to impart an aesthetic textural appearance. The individual yarns of the woven fabric are preferably substantially uniformly coated with a polyvinyl chloride plastisol to impart stain and wear-resistance, inhibit the growth of molds, fungi, bacteria and the like, and to enhance the appearance of the exposed face of the lamina. The moisture-permeable lamina structure allows wall covering paste, used to adhere the lamina to a wall, to dry at an acceptable rate, yet does not allow paste to bleed through the foraminous woven fabric layer.

Abstract: An acoustic structure for use as a sound insulator in a jet engine is disclosed. The structure, which is carried in a sound-absorbing compartment of the engine, includes a framework and an acoustical insulation material disposed within the framework. The material is composed of a rigid matrix of randomly oriented, fused silica fibers having fiber diameters predominantly in the range 2-8 .mu.m, a three-dimensionally continuous network of open, intercommunicating voids, a flow resistivity between about 10-200K rayls/m, and a density of between about 2 and 8 lb/ft3. Also disclosed are a clad acoustical structure for sound attenuation in a jet engine, where operational temperatures exceed current jet engine designs, and a method of attenuating jet engine noise.

Abstract: A sound insulating membrane and processes for forming, particularly well suited for use in floor, ceiling and wall constructions. The membrane comprises at least one backing layer in contact with a layer of polymeric material. The polymeric material has an elongation factor of about 500% to about 900% and a Shore A hardness of from about 65 to about 80 points, 5 seconds. In a preferred embodiment, the polymeric material comprises 40-70% chlorinated polyethylene, 20-30% ethylene vinyl acetate, and up to 10% polyvinyl chloride. Floor, ceiling, and wall constructions and related methods utilizing the sound insulating membranes are also disclosed.

Abstract: There is described a sound-insulating power vehicle part which includes a shaped outer sheet and an acoustically effective inside packing which together form an inherently stable lightweight composite part. To obtain this, a thermosetting plastic is used for the outer sheet while the inside packing is formed of a fiber-resin fleece, which is only slightly compacted in an acoustically effective main area and is closely compacted in its stabilizing areas.

Abstract: A sound-barrier panel includes an acoustic layer that comprises chipped rubber and cord fiber from tires and a structural concrete layer bonded to the acoustic layer by a combination composite bond that includes both a mechanical portion and a chemical portion. The panel is formed in a special process that can define panels of various sizes, such as twelve feet by twenty-five feet in size. The panel has a high sound absorption capability and a high sound transmission loss, especially at low frequencies, and is extremely weather resistant and durable. The panel is also durable and cost effective and utilizes what otherwise would be potential hazardous waste.

Abstract: A sound absorbing member having excellent sound insulating and absorbing performances comprises a fiber assembly consisting essentially of short fibers and having a thickness of not less than 5 mm, in which new and/or recycled polyester fibers are used as the short fiber and not less than 30% by weight of the polyester fiber used have a fiber-size of not more than 4 denier.

Abstract: The method according to the invention for the manufacture of a noise-transmission-reducing covering (1) with essentially an insulation composite (3) and a carpet covering (5) proposes to configure both the carpet covering (5) and the insulation composite (3) so that a sound field (17) can couple with a spongy mass layer (11) and be absorbed into this layer. A preferred embodiment has at least one suitable insulating barrier coating (19), in order at least to protect the spongy mass layer (11) from contamination.

Abstract: The present thermal shield comprises, in essence, a dimensionally stable substrate (2) on which is disposed a sound-absorbing thermal insulating layer (3). This thermal insulating layer is provided with a protective coating (4). According to the disclosure, all layers of the thermal shield consist of a light metal, particularly of aluminum or an aluminum alloy. For acoustic reasons, the thermal insulating layer is made up of an open-pore structure, especially of aluminum wool. In a further development, the thermal insulating layer is made up of several plies, and the dimensionally stable substrate (2) is perforated. A thin protective layer (5) acting as a foil absorber is arranged between the substrate (2) and the thermal insulating layer (3). This thermal shield is utilized with preference in the automobile industry.

Abstract: A glass fiber structural panel has one or more planar, thin, high density, glass fiber mat laminates. Each glass fiber mat laminate has layers of glass fiber mat and intermediate layers of pliable, thermoplastic adhesive adhesively bonding the layers of glass fiber mat together to form the planar, thin, high density, glass fiber mat laminate which, after being folded through 180.degree., will return to a planar condition without wrinkles or creases in the major surfaces of the laminate. Bower density glass fiber backing or core layers can be adhesively bonded to the planar, thin, high density, glass fiber mat laminates to inexpensively increase the thickness and sound absorbing properties of the structural panel.

Abstract: The present invention provides a membranous-vibration sound absorbing material which can achieve not only good sound absorbing characteristics, workability and strength but also transparency. The membranous-vibration sound absorbing material can also achieve dust-proof and dust-free properties when necessary and can be suitably used for application in clean rooms and the like.

Abstract: A non-reflecting, wave-absorbing structure absorbs sound, radio and radiation wave. The non-reflecting, wave-absorbing structure combines an outer non-reflecting wave structure and a wave-absorbing portion. The outer non-reflecting wave structure allows for the transmission of the wave therethrough without appreciable reflection and the wave-absorbing material absorbs substantially all of the transmitted wave. In the case the wave to be absorbed in a sound wave, the wave-absorbing material is preferably an epoxy in a chemical state of gelatinization which is prevented from reaching a state of cure.

Abstract: An insulating laminate, which is particularly suitable for a sound attenuating barrier, such as a contoured vehicle headliner. The disclosed embodiment includes a finish lamina, which may be preferably cloth-like, and a substrate which is preferably structurally stable and self supporting and which may be adapted to absorb sound primarily at predetermined higher frequencies. In one preferred embodiment, a thin flexible film is located between the finish lamina and the substrate which is adapted to absorb sound primarily at relative lower predetermined frequencies. The film may include a pattern of openings or holes designed to absorb sound primarily at predetermined lower frequencies. In the disclosed embodiment, the substrate includes a porous fiber mat, preferably including fibers having a range of thicknesses to improve sound attenuation at higher frequencies, a structural foam lamina and a reinforcing scrim, preferably comprising spunbonded polyester filaments.

Abstract: Acoustic absorption and vibration damping materials are produced by mixing electrically conductive particles or strands into a piezoelectric matrix material. The electrically conductive particles or strands act as small localized electrical short-circuits within the matrix material and effectively dissipate the electric charges produced by piezoelectric effect from the pressure of acoustic or vibrational energy as heat. All energy thus converted into heat is subtracted from the original acoustic or vibrational energy, resulting in acoustic absorption and/or vibration damping.

Abstract: The invention describes a foamed material panel, in particular a shaped part composed of one or several foamed material panels. These panels consist of a soft and, if appropriate, elastic foamed material comprising cellular webs and/or cellular walls that are permanently deformed at least in some areas. A central area of the foamed material panel is plastically deformed to a higher volumetric weight than at least one intermediate area of the formed material panel.

Abstract: A roof construction has vibration dampening ability and includes a body member in contact with a waffle-like surface of a moulded porous compressed fibrous web which is designed to have a self-supporting stability. The waffle-like surface exhibits an anisotropic air resistant structure.

Abstract: The present invention relates to sound transmission barrier and/or sound absorption media systems that are especially useful in motor vehicles and boats. These systems are based on the concept of replacing the traditional intermediate high-mass layer ("massback") with two or more high-mass layers that are separated by a strong yet light material, such as polyurethane foam.

Abstract: A panel absorbing acoustical energy at low, medium and high frequencies, particularly at frequencies ranging from 400 Hz to 5,000 Hz, is essentially constituted by a plate (1) of semi-rigid foam with open communicating cells and by a layer (2) of bonded fibers or by a flexible cellular material. The assembly acts according to a mass-spring principle. The plate (1) of semi-rigid foam with open communicating cells constitutes the mass of the assembly functioning according to the mass-spring principle, while the layer (2) of bonded fibers or of flexible cellular material constitutes the spring of this assembly. The foam comprising the plate (1) is preferably a semi-rigid polyurethane foam of a density ranging from 20 kg/m.sup.3 to 50 Kg/m.sup.3, of a thickness comprised between 5 mm and 15 mm and whose permeability to air is comprised between 5 liters per minute and 45 liters per minute for a specimen 80 mm in diameter. The layer (2) constituting the spring has a stiffness ranging from 0.007 MPa to 0.

Abstract: Disclosed is a novel acoustic insulator constituted by a shaped article obtained by adding a binder to shreds of a plastic coated with a magnetic material, such as a magnetic tape or magnetic sheet and shaping the same into a sheet or a block having a bulk specific gravity of 0.05 to 0.4 and a gas permeation resistance of 3 to 90 dyn.S/cm.sup.4. Alternatively, shreds of a plastic coated with a magnetic material, such as a magnetic tape or magnetic sheet, are filled into casing members so that the bulk specific gravity of the composite product is 0.05 to 0.4 and its gas permeation resistance becomes 3 to 90 dyn.S/cm.sup.4.

Abstract: A passive damping mechanism for a panel member in which a bonding layer is disposed on each side of the panel, a damping layer is disposed on each of the two bonding layers, and a constraining layer is disposed on each of the two damping layers. Each of the above-mentioned layers is coextensive with the respective panel surfaces to which it is attached. The bonding layers are preferably made of an aramid fiber material. The damping layers are preferably made of a viscoelastic material. The constraining layers are preferably made of an aluminum-graphite metal matrix composite material. In addition, the coefficient of thermal expansion of each bonding layer should match well with that of each constraining layer.

Abstract: Vibration damping composites suitable for use in construction panels or constrained-layer elements are described. The composites include a viscoelastic gel prepared from 99.5-92.5 wt. % water and 0.5-7.5 wt. % of a superabsorbent polymer. Preferably, the polymer is of the carboxylic acid type and optionally includes starch or cellulose.

Abstract: A sound absorption laminate comprises a porous insulation substrate, such as, a thermoplastic glass or polymeric fiber blanket or a foamed polymeric resin sheet and a facing sheet with a high air flow resistance. The facing sheet is adhered to a surface of the porous insulation substrate to augment the acoustical properties of the substrate. With the facing sheet the air flow resistance of the laminate is greater than the air flow resistance of the substrate and the laminate exhibits a higher sound absorption coefficient than the sound absorption coefficient of the substrate. Thus, the laminate exhibits better sound absorption properties than the substrate and is suitable for sound absorption applications for which the substrate alone would not be suitable.

Abstract: Acoustic resonator means are embodied through successive stages of molding. A first stage pre-forms resonator enclosures without solid forms inside. After resonator enclosures have been pre-formed they advance to a second stage. A jig form molds pre-formed resonator bulbs and concrete together in a panel molding region to form a resonator panel.

Abstract: A noise attenuation panel 10 for an aero engine environment comprises a first cellular component part 121 which has wall portions which extend from the front face to the rear face and which provide bounding surfaces for an array of cells 15 and a second cellular component part 122 in the form of an open-celled structure having a multiplicity of the intercommunicating cells obtained by aggregation of particulate material or by the displacement of material by a dispersion or like technique. A backing component part 11 is secured to the rear face of the second cellular component part 121, the front face of which is secured to the rear face of the first cellular component part and a facing component part 14 is secured to the front face of the first cellular component part. In an alternative form, the positions of the cellular component parts 121, 122 are interchanged.

Abstract: An acoustical barrier wall system for use as an external wall acoustical attenuator for sound sources, is disclosed. The wall system comprises a plurality of acoustical barrier panels adapted for vertically stacked co-operating engagement. There are first and second attachment members each having a first end anchored within the main body portion of the acoustical barrier panels and an opposite threaded second end extending outwardly beyond the main body portion. There are first and second upright bracing members, each having a corresponding plurality of attachment member receiving means spaced therealong, the attachment member receiving means being adapted to receive the respective first and second attachment members therein. Connecting means in the form of co-operating nuts adapted to connect the attachment members and the attachment member receiving means in secured relation to one another.

Abstract: A moisture-permeable acoustic lamina which is usable as a wall covering has a foraminous woven fabric layer adhered to a fabric backing by a discontinuous thermoplastic polymer layer. The woven fabric preferably has an embossed undulate outer surface to enhance the acoustic properties of the lamina and to impart an aesthetic textural appearance. The individual yarns of the woven fabric are preferably substantially uniformly coated with a polyvinyl chloride plastisol to impart stain and wear-resistance, inhibit the growth of molds, fungi, bacteria and the like, and to enhance the appearance of the exposed face of the lamina. The moisture-permeable lamina structure allows wall covering paste, used to adhere the lamina to a wall, to dry at an acceptable rate, yet does not allow paste to bleed through the foraminous woven fabric layer.

Abstract: The present invention is a thermal and acoustical insulation wall panel assembly that incorporates a synthetic vinyl. This panel assembly reduces the amount of hazardous waste and the cost of manufacturing, shipping and installing the insulation. The panel is comprised of a plurality of superimposed layers. One layer is a rigid facing which is preferably corrugated for supporting the panel. Attached to this facing are, in sequential layers, a thermal-insulating batt, a mass-loaded vinyl sheet for acoustic-insulation, a second thermal-insulating batt, a heat-reflective backing, and a retainer. A plurality of connectors are used to hold the plurality of superimposed layers together.

Abstract: A method and article for damping acoustic energy caused vibrations comprises forming a damping surface comprising an alloy containing from about 13.5 to about 24.5 atom percent tin with the balance being essentially titanium or a titanium-chromium alloy containing from about 52 to about 56 atom percent chromium, about 8 to about 12 atom percent aluminum, and the balance essentially titanium.

Abstract: Soundproofing materials consisting essentially of zinc oxide whisker particles having a nucleus body and needle crystal portions extending radially from the central body in different plural directions. The materials may comprise a support material for supporting the zinc oxide whisker particles. Such support materials include inorganic materials such as metals, ceramics, glasses, cements, mortars and various fillers in the form of powder, flakes, fibers and the like, and organic materials such as resins, rubbers, waxes and the like. These materials are particularly suitable for sound insulation, sound proofing, vibration damping and vibration insulation.

Abstract: A substantially enclosed sound absorbing unit for an anechoic chamber is disclosed. The sound absorbing unit includes a substantially flat panel member comprising a layer of sound absorptive material. An anechoic member is disposed adjacent to the flat panel member. The anechoic member is disposed adjacent to a base and a generally spaced apart sound transparent wall member. The wall member includes a layer of sound absorptive material and a cover sheet made of perforated, substantially sound reflective material. The free space of the perforated cover sheet is at least 7 percent of the total area of the cover sheet.

Abstract: An absorber for electromagnetic and acoustic waves comprising an absorber body containing mineral wool and particles of a conductive substance, in which the mineral wool is impregnated with a binder having the particles admixed therewith.

Abstract: A method for attenuating sound waves passing from a source area to a receiving area comprises the steps of providing a nonwoven acoustical insulation web comprising thermoplastic fibers, the web having an average effective fiber diameter of less than about 15 microns, a density of less than about 50 kg/m.sup.3, and an air pressure drop across the web of at least about 1 Mm water at a flow rate of about 32 liters/min.; and positioning the web between the source area and the receiving area such that a major face of the web intercepts and thereby attenuates sound waves passing from the source area to the receiving area. Also, a laminate adapted to be applied to the inner panel of a vehicle door comprises the web and a second layer, such as a scrim, nonwoven fabric, film, or foil, laminated thereto. The laminate can be applied to the inner panel of a vehicle door so that the second layer provides water barrier protection and the web provides acoustical insulation.

Abstract: For under hood sound-deadening of vehicles a molded sheet (14) of impregnated non-woven fabric sheet material having a weight in the range 0.5 to 0.75 kg/m.sup.2 and a density in the range of 350 to 425 kg/m.sup.3 is used. The material includes a blend of polyester staple fibers having an average decitex in the range 2.5 to 4.0 dtex typically 3.2 dtex. The impregnant includes 10 to 35% by dry weight carboxylated styrene-butadiene copolymer in which the styrene content is not less than 55%, 5 to 10% by dry weight carboxylated styrene-butadiene copolymer in which the styrene content is not more than 50%, 50 to 70% by dry weight mineral filler, and up to 3.5% by dry weight melamine formaldehyde resin. Pigment may also be added. The fabric sheet material is preferably clipped to the hood underside to provide a small air gap between the material and the hood, but alternatively the sheet material may be bonded by adhesive to the hood underside.

Abstract: Composite soundproofing panels for applications in the automotive sector have a plastic layer bonded to at least one porous material layer. The plastic layer has a composition which contains a first elastomeric material, a high density filler material, a plasticizer and a second elastomeric material. The plastic layer is bonded to at least one self-supporting, premoldable layer of porous material while maintaining a constant thickness within +10%.

Abstract: A plurality of small blocks are disposed between an upper flexible layer and a more rigid and thicker layer. The blocks prevent the compression of portions of the carpet surrounding the area on which a load, such as the passengers feet, is placed. By preventing the compression of the major portion of the carpet, essentially unchanged carpet transmitivity characteristics are maintained.

Abstract: An insulating laminate, which is particularly suitable for a sound attenuating barrier, such as a contoured vehicle headliner. The disclosed embodiment includes a finish lamina, which may be preferably cloth-like, and a substrate which is preferably structurally stable and self supporting and which may be adapted to absorb sound primarily at predetermined higher frequencies. In one preferred embodiment, a thin flexible film is located between the finish lamina and the substrate which is adapted to absorb sound primarily at relative lower predetermined frequencies. The film may include a pattern of openings or holes designed to absorb sound primarily at predetermined lower frequencies. In the disclosed embodiment, the substrate includes a porous fiber mat, preferably including fibers having a range of thicknesses to improve sound attenuation at higher frequencies, a structural foam lamina and a reinforcing scrim, preferably comprising spunbonded polyester filaments.

Abstract: An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

Abstract: An insulating element for buildings and more particularly for walls, ceilings and roofs, consists of a sheepswool fleece which is sandwiched between two layers of needled non-woven material consisting of sheepswool. The fleece and the needled non-woven material are connected together by fibers thereof to constitute a unit able to be handled as such.

Abstract: A two-layer, vibration-absorbing and anti-corrosive, abrasion-resistant coating for rigid substrates, in particular for sheet metals in the underbody region of motor vehicles, for reducing the noise caused by impacting particles, comprises an inner layer, facing the substrate, of a polymer A and a plasticizer P.sub.1, and a covering layer of a polymer B and a plasticizer P.sub.2, such that either the polymers A and B have a different chemical composition and the polymer A is essentially incompatible with the plasticizer P.sub.2 and the polymer B is essentially incompatible with the plasticizer P.sub.1, or both layers contain essentially the same concentration of one plasticizer (P.sub.1 =P.sub.2), so that there is no risk of one layer being impaired by the plasticizer from the other layer.

Abstract: A device is provided preventing the transmission of sound, the device being fabricated of polymer composition and comprising a hollow core member formed of fiber-reinforced thermosetting resin, and at least outer member formed of unreinforced thermoplastic resin which is friction fit to the core member. The core member and outer members are preferably formed by pultrusion and extrusion, respectively. Adjacently disposed devices are connected together to form a fence-like barrier through which few or no sound waves are allowed to pass. This system is advantageously used to prevent sound waves emanating from a large transportation structure such as a highway, railroad track, or airport.

Abstract: A file cabinet is disclosed which has a door with high sound absorption properties. The door has metal front and rear panels and an intermediate layer of sound absorbing material sandwiched therebetween. An array of openings are cut through both the front and rear panel. Sound impinging on the front panel enters the cabinet via the door and is attenuated in the door and cabinet. Preferably, paper files are stored within the file cabinet with their peripheral edge surfaces disposed towards the rear panel to assist in attenuating sound within the cabinet.

Abstract: A tubular sound absorbent device includes the cylindrical wall closed by top and bottom end walls to define an internal chamber. Located within the chamber are various sound wave attenuating devices including those of tubular configuration as well as those of frust-conical shape. The sound wave attenuating components may also include perforated tubes entirely confined within the sound absorbent unit or with a tube extending outwardly for termination in a companion structure.

Abstract: A lay-in ceiling panel structure, comprising a glass fiber ply, a gypsum board, and a highly perforated vinyl lamina. The ceiling panel structure having noise and sound transmission reduction coefficients in the range of 0.85 to 0.95 sabins and 0.35 to 0.39 dbs respectively. This structure also provides good fire resistance, space efficiency, and a lower surface that is washable and pleasing to the eye. In addition, the glass fiber ply is secured to the gypsum board by droplets of glue which are spaced 1 to 2 inches apart and which are applied 4 to 6 inches away from the outer periphery of the gypsum board. Applying the glue in this way allows the glass fiber ply and vinyl lamina to lay flat even if the board is warped by water leaks, humidity or age.