Specific acoustical properties or dimensions

This invention concerns a multi-layered acoustic liner which breaks up high amplitude sound and shock waves into several waves of the same type but smaller amplitudes, converting some acoustic energy into heat and shifting part of the acoustic energy to a higher frequency level to achieve better absorption...     

A lock core panel wherein a face sheet, base sheet and core are integrally joined at each web line by fiber material prior to curing. The upper face sheet comprises layers which may be angularly oriented and selected fibers or strands removed, if desired, to provide desired porosity for noise suppression...     

A sound deadening system is provided, comprising a laminate of a covering stratum of closed-cell soft foam having a bulk density of less than about 50 kp/m.sup.3, and a core stratum having cavities and joined to the covering stratum at locations spaced from one another by a distance less than about 10...     

This invention is a new and unique acoustical board formed of fire retardant materials which board has the unique qualities of being fire retardant, sound absorbing, heat insulating, and decorative, and may be formed virtually in any desired size and shape. It is composed of fiberglass reinforced melamine...     

A hard board containing a fiber web and a thermoplastic resin which composite is used as a noise absorption product is improved in that the surface and spaces between the fiber web are covered and filled with the resin, and wherein a plurality of finely formed crevices is formed in the resin covering...     

A laminated glazing pane comprised of at least two sheets of vitreous material joined together by an intervening layer of plastic material given improved sound attenuation properties by constructing the pane in such a manner that its base frequency (f) is between 0.70 and 0.97 times its theoretical base...     

A sound-attenuating inlet duct is provided for a gas turbine engine wherein the inlet duct includes a casing defining, in serial flow relationship, a minimum area throat of predetermined axial extent, a diffuser and a cylindrical section. Sound-absorbent acoustic material is disposed upon the inner walls...     

A structure that is preferably constructed in sheet form and that provides improved sound attenuation with a relatively small thickness. The materials comprising the structure include a myriad of hollow glass microspheres interspersed, preferably by a blending process, into a curable resin base. Improved...     

A sound barrier and sound-absorption panel preferably of a transparent nature so as not to interfere with vision of and light for the machine or other noise-emitting device, to be shielded or enclosed by one or more of the panels. The panel is formed of transparent sound-reflecting material and sound-absorbing...     

An acoustical laminate comprising multi-ply glass fabric impregnated with an epoxy resin and a method of manufacturing the laminate. The laminate may be bonded to suitable backing, such as a honeycomb core with a solid backing, to produce an acoustical panel. The panel provides excellent, substantially...     

A sound absorbing body which can effectively be utilized as an exterior sound absorbing wall or an interior wall of a house is disclosed. The sound absorbing body comprises a number of sound absorbing cavities inclined at an angle .alpha. which is smaller than 80.degree. with respect to a transverse...     

A shield for an assembly includes a member of generally corrugated construction, which is uniquely configured to substantially prevent the passage of liquid contaminants impinging thereon. The invention is especially concerned with the provision of an acoustical assembly employing such a shield.

A vibration damper for damping sound propagating in solids includes vibran damping horn members connected through a damping material to a support point on the surface of the solid in such a manner that a tapering portion of the horn member contacts the solid through the damping material. The taper in...     

A silencer device for attenuating fluid borne noise has a flow through housing with an open upstream end for the entrance of a fluid into the housing and a coaxial open downstream end for exhausting the fluid from the housing. An entrance header formed of a plurality of spaced apart intersecting elongated...     

This invention relates to acoustic liners having a plurality of cavities defining Helmholtz resonators in which the adjacent cavities are asymmetrical causing a pressure imbalance across the coupling means (tube, slot or aperture) between these cavities in the frequency range of interest. Such liners...     

A plurality of parallel and laterally spaced impermeable walls define an array of side-by-side elongate fluid filled cavities. Adjacent open ends of the cavities provide a sound-receiving or admittance end for the sound waves into the cavities. An acoustically reflective, preferably impermeable, barrier...     

The present noise reducing apparatus includes resonators which have a small and variable volume as well as a high admittance. For this purpose the resonators constitute vibrating systems having at least one volume wherein the pressure is reduced below atmospheric pressure to provide a reduced volume...     

A noise control device which produces behind it an enlarged sound reducing region is disclosed. The device comprises a hollow structural body composed of a plurality of elongate hollow passages which are different in length and constructed such that the passage length is made the longest at a substantially...     

The present noise absorbing or damping devices are shaped as funnels or horns of various configurations which may be coiled, spiraled, rolled and/or bent or twisted. The open funnel mouth of each funnel faces toward the source of the noise. The volume confined by the funnel walls may be filled with noise...     

A centrifugal fan is treated acoustically by the provision of tuned noise absorption cavities preferably including absorbent infill between an acoustically permeable scroll and casing of the fan. Alternatively, or in addition an acoustically absorbent panel structure is provided in spaced confronting...     

This invention relates to acoustic liners having a plurality of cavities defining Helmholtz resonators in which the adjacent cavities are asymmetrical causing a pressure imbalance across the coupling means (tube, slot or aperture) between these cavities in the frequency range of interest. Such liners...     

An acoustical wall panel has a core of a plurality of layers of glass fiber pressed together and having a density ranging from approximately two pounds per cubic foot at the front surface to approximately six pounds per cubic foot at the rear surface. A plurality of cavities are formed on the front surface...     

An acoustical insulating material comprises a fiber reinforced lead composite sheet or panel. In a preferred embodiment of the invention the fibers are substantially axially parallel aligned with one another. The frequency absorption and transmission characteristics of the material may be varied by mechanically...     

A floor-standing acoustic space divider has an upward and outward protuberance along the top edge of at least one of its sides. The protuberance increases the acoustic shadow of the space divider, reflects direct sound back into the area from which it originates, improves speech privacy in open plan...     

An acoustical panel for reducing acoustic noise is disclosed. The panel is comprised of a corrugated sheet of material. The sheet of material has a generally parabolic-sinusoidal configuration forming a plurality of corrugations. The corrugations extend in a first direction and form a plurality of peaks...     

A multi-layer acoustic lining is of the type having core compartments rendered effective as Helmholtz resonators by means of resonator necks projecting from the core facing layer into the core compartments. In order to broaden the frequency response, those ends of the resonator necks which project into...     

Combination bulk absorber-honeycomb acoustic panels particularly adapted for use in the inlet and fan air duct of a fan jet engine are disclosed. Each panel comprises a broadband noise-suppressing bulk absorber layer mounted between a back sheet and a perforated septum; and, a narrow band noise-suppressing...     

A laminated noise attenuation panel for both sound absorption and sound transmission loss having as its principal layers an expanded thermoplastic core with alternately inverted cavities, half opening to each side of said core and a sheet of cured resinous material having hollow microspheres with substantially...     

A plurality of parallel and laterally spaced impermeable walls define an array of side-by-side elongate fluid filled cavities. Adjacent open ends of the cavities provide a sound-receiving or admittance end for the sound waves into the cavities. An acoustically reflective, preferably impermeable, barrier...     

A sound-absorbing structure comprising a plurality of linear and parallel grooves in the surface of the structure and ribs between the grooves. The structure is employed to damp, in a semi-space which is delimited by a substantially plane surface, e.g. a ground surface, a sound field propagating essentially...     

An acoustical-reflective ceiling panel for directing incident light from a remotely positioned light source toward a selected area and for attenuating ambient noise. The panel includes a plurality of pyramidal reflector units arranged in an array of rows and columns and a plurality of acoustical holes...     

The present invention relates to a noise shield including a massive shield wall and an attachable absorbent unit on the shield wall. Thus the noise shield can be used with the absorbent unit along the parts of the road where you do not want reflections of the noise which you want to reduce and without...     

Apparatus for attentuating noise emitted from an inlet port to a centrifugal fan comprises a panel member which is mounted in spaced confronting relationship to the inlet port and includes a rigid backing member, a facing mounted in spaced disposition from the rigid backing member, partitions dividing...     

This invention pertains to asphaltic sheet sound deadener for use as a vibration damping medium, which can be bonded in place without excessive sag or flow by subjecting the material to 250.degree.-400.degree. F. The main use of this material is in the automotive field, but may be used in other areas...     

A multi-layer acoustic lining, e.g. for a flow duct in a gas turbine aeroengine, includes Helmholtz-type and tube-type resonators sandwiched between backing and facing sheets. In the invention, the ends of the tube-type resonators abut the Helmholtz resonators but are acoustically divided from them by...     

A non-porous, sound-absorbing panel which can be readily cleaned and which is intended for use in high humidity, sanitary environments. The panel comprises two non-porous membranes or panels bonded to opposite sides of a honeycomb structure. At least one membrane is formed of sound-absorbing material...     

An acoustic space absorber unit is provided in which Helmholtz resonators are mounted within an enclosure composed of sound absorbing material, with the orifices of the resonators near to but spaced from the enclosing material. The Helmholtz resonators are tuned to low audible frequencies such as 125...     

A plurality of parallel and laterally spaced impermeable walls define an array of side-by-side elongate fluid filled cavities. Adjacent open ends of the cavities provide a sound-receiving or admittance end for the sound waves into the cavities. An acoustically reflective, preferably impermeable, barrier...     

Airborne-sound-absorbing wall or ceiling paneling comprises a perforated plate having a hole-area proportion L and a nonwoven fabric bonded thereto by a discontinuously distributed adhesive layer. The nonwoven fabric has an open-area proportion N and an air flow resistance W.sub.v in the zones free of...     

A sonic reflector comprising three mutually perpendicular walls of sound reflective material each of a generally right triangular shape. Plural arrays of such reflectors provide acoustical panels useful in assisting performers in monitoring their own performance on stage and in delivering enhanced sound...     

A tuned sound barrier for machines which radiate sound primarily at a few constant, discrete frequencies includes an array of mechanical resonators distributed over the surface of a sound barrier. Each resonator of the array is tuned to present a high mechanical impedance to transmission of mechanical...     

An acoustic lining for a flow duct has a first perforate skin fixed to an underlying sound-absorbing layer. The first perforate skin is overlain by a second perforate skin which forms the wall of the flow duct. One of the skins is relatively moveable in a sliding sense with respect to the other skin...     

Viscoelastically damped reinforced skin structures wherein a sandwich skin having a relatively thick core is supported by structural elements, such as stringers and frames, are disclosed. In one form (FIG. 1), a main skin (15) is supported by stringers (13) that are in turn supported by frames (11)....     

A duct lining exposing a substantially smooth, liquid impermeable outer surface to fluid flowing therealong.

A sound suppressor liner for aircraft exhaust passages is described which is based on the Helmholtz resonator principle including an inlet passage leading into a closed cavity wherein the inlet passages defined by a pair of curved walls with one wall being concave and the other wall being convex and...     

A noise control apparatus for reducing a sound volume of a noise propagating from a noise source such as a railroad includes a sound arresting wall placed apart from the noise source. Means for shifting in phase and refracting the acoustic wave of the noise is disposed at substantially the top of the...     

An acoustical control media includes an air impervious septum adjacent which there is positioned a relatively thick layer of low density filler material on the outside of which there is provided a relatively thin panel of medium density perforated material. The acoustical media so formed can be used...     

A plate-component (1) which can be used for airborne-sound insulation has chambers (5, 6) filled with a pulverulent or granular, e.g. metallic material, whose chamber walls (2, 3, 4) at least partly are formed by a flexible material. Chambers (5, 6) are small in the vertical direction, but in the horizontal...     

It should be possible to manufacture, in a simple manner, a sound-absorbing wall-lining (3) consisting of a material to be applied to the wall which needs lining, and a resilient layer (4, 5) of foam, e.g. foam rubber, felt, or similar material, having locally distinctive sound-absorbing capacities,...     

A septum (18) is installed at a desired depth within a section of honeycomb core (12) for use in a sound attenuation panels, the septum is sandwiched between two layers (20, 24) of support material having a melting temperature intermediate between the fusing and curing temperatures of the septum material....     

An annular groove formed on the inner surface of the porous sheet of an acoustical aircraft or jet engine liner spaced from the front edge and adjacent to the adhesive bonding material serves to prevent dislodgement of the entire porous sheet upon an impending peeling of the porous sheet. The groove...     

The invention relates to a noise reduction lining of the kind for use in passenger compartments of automobiles for absorbing engine noise of five or six cylinder combustion engines, and comprises between a cover layer and a base layer an absorption layer of open-pored elastic material into which is embedded...     

A panel having a cellular core and an acoustically semi-transparent facing is provided. The core, which may be a honeycomb, has cells opening to a face of the core. The facing is bonded to the face of the core such that pillow-like portions of the facing extend into the open cells of the core to provide...     

The disclosure is directed broadly to a thin metal sheet containing a multitude of small openings therethrough. Typically, the sheet will contain at least 400 openings per square inch with the openings having an average cross-sectional area of from about 0.0005 to about 0.005 square inch. The sheets...     

Two pelts of fiberglass are bonded together to form a sound absorption panel. One pelt is deformed to a sawtooth shape and the teeth of the sawtooth pelts are bonded into grooves in the other pelt which is essentially flat except for the grooves.

An acoustic enclosure (10) has interconnected sound reducing panels forming a substantially rectangular structure which is configured to house a computer printer. Each side (12,14) panel is a multiple strata panel having an outer polymeric stratum (26), a multiple channel intermediate thermoplastic stratum...     

A method of absorbing sound generated within a clean-room environment and the sound-absorbing panel for carrying out that method, wherein said sound absorbing panel comprises a fibrous core material enclosed in a non-porous membrane, said membrane being attached to at least one of the extensive surfaces...     

In sound absorbing lining, conduits (4) are provided, filled with a viscous damping fluid, and are in contact by their ends facing towards the rigid supporting wall (1) to which the lining is applied with flexible cells containing a gas and forming a readily compressible material, for example foam rubber...     

A sound barrier (22) comprising a pair of spaced apart members (24,26), a medium (34) disposed between the members capable of propagating sound waves, and one or more acoustical resonators (30) coupled to the medium and tuned to one or more selected frequencies. The resonators may be disposed between...     

Described is an acoustical panel to control sound emissions in facilities requiring sanitary conditions. The panel incorporates a moisture proof outer shell, one or more air pockets and a woven inner core. The panel controls sound through transmission, absorption and dispersion.

This invention relates to an acoustic energy absorbing material which abss sound energy underwater and its performance is independent of the surrounding hydrostatic pressure. It consists of a non-conducting elastomeric matrix having piezoelectric or magnetostrictive particles disposed therein for converting...     

A movable, prefabricated wall panel having a rigid rectangular frame. A core structure is disposed in the region bounded by the frame, which core structure preferably comprises at least one honeycomb layer. Sheetlike skins are fixedly secured to opposite sides of the frame and extends across the region...     

A partition (4) for separating the engine compartment (2) from the passenger compartment (3) of a motor vehicle comprises a wall (5) and a covering (6) of noise-insulating material on the engine compartment side of the wall. The partition (4) has convex or concave deformations (8, 9, 11) in one or several...     

In the present invention an improved sound absorbing panel is provided. The panel comprises an array of wall defining means configured to provide two or more contiguous hollow cells having adjacent open ends and adjacent closed impermeable ends, the open ends defining a sound receiving end of the array,...     

The lightweight underwater acoustic baffle with enhanced performance chareristics particularly at low frequencies is provided by a stiffened resistive screen means affixed in front of a compliant material for allowing the baffle to reflect on the compliant side and on the screen side, a rigid irregular...     

An acoustical wall panel for mounting on walls or similar surfaces includes a wooden support frame, low density fiberglass batts positioned within the support frame, and a generally rigid acoustical board positioned in front of and against the frame. A sheet of material is attached to the back of the...     

A sound insulation part for surfaces with known source-sink distribution, in particular in passenger spaces of motor vehicles, is provided, which is designed as a mass-spring system with discontinuities incorporated therein for the purpose of converting sources into sinks. In order to achieve a particularly...     

A foam acoustic absorption member having a stabilizing layer with perforations and, in order to obtain a simple, stable structural shape of homogeneous resistance to flow, the stabilizing layer (2) is a wide-side wall of a hollow body (K) which wall is pressed, under thermal deformation, against the...     

An acoustic energy absorbing baffle comprising a fluid containment means having an acoustic window means, a viscous fluid contained within said fluid containment, a porous material comprising strands of wire and being immersed within said viscous fluid means, a compliant mass means and means for holding...     

A three-dimensional, formable constructional element (1) with acoustic properties is provided, having a shell (2) with a low natural bending stiffness to which webs (3) are fixed so as to form a cellular grid. It is important that over the whole extent of the shell (2) the dimensions both of the webs...     

The propagation of sound in flow channels is attenuated by a sound attenuating box comprised of cell-like chambers each with a bottom, an outer plate and a partition with an opening spaced from the outer plate such that the Helmholtz resonator established by the sub-chamber between the bottom and the...     

Disclosed herein is an improved sound absorbing diffusor device wherein the surface designed to face the sound source includes a plurality of sound absorbing wells of equal widths but different depths separated by thin sound absorbing dividers. The depths of the individual wells are based upon the quadratic-residue...     

The instant invention involves a sound absorbing structure which is formed from at least two adjacent panels which are assembled so as to provide a narrow slot of between about 1/16 and 3/4 inch between the panels. The slot opens into a resonance cavity formed by the panels, their support strips, and...     

The invention relates to an adhesive insulating system (3) that is non-destructively removable, e.g. for repair purposes, for sound insulation of partition walls (1), particularly in motor vehicles. Between the foundation and the overlying layers of the insulating system (3) a layer (2) of a highly under-cross-linked...     

The apparatus for making artificial snow by atomizing water comprises a ductlike housing mounted on a supporting frame, in which a blower is positioned and on whose downstream end a plurality of nozzles or orifices for spraying water or a water-air-mixture are provided. The ductlike housing is constructed...     

A perforated panel having a thickness of at least about 6 mm, for use as a sound absorbing element, especially at lacunarias. Each perforation is covered by a thin fiber cloth which is bonded to the edges of the perforation, rendering said panel element a specific acoustic flow resistance of between...     

A volumetric sound absorber for audible sound frequencies is made from a thin sheet material that is permeable to air with thickness mass, and flow resistance within specified ranges.

An acoustic tile that provides soundproofing in a modular wall, such as is used in a modular panel office system, comprises a rigid rectangular metallic frame, a septum formed of a calcium carbonate-filled molded synthetic rubber polymer, a layer of low-density fiberglass and a layer of high-density...     

Nylon impression fabric is used as a cover fabric for an acoustical material (e.g., 1 inch thick polyester foam) substrate in an environment--such as a textile workplace environment having textile machinery such as texturing air jets--to provide for good sound absorption while being easily cleanable,...     

A noise reducing apparatus in the form of a hollow body comprising two or more passage groups consisting of a plurality of passages. The length of each passage is determined such that the sound waves emitted from the passages of the adjacent passage groups form plane waves which are shifted by a half...     

A sound absorbing structure is formed of adjacent panels which provide narrow slots opening into first resonance cavities formed behind the panels. Support strips provide secondary cavities between adjacent first cavities to reduce acoustical coupling between adjacent first cavities. The resulting sound...     

To manufacture an anechoic coating which prevents a wall from reflecting acoustic waves, the wall is coated with an elastic material of low compressibility, which is highly absorbent under shear stresses, and then with a highly compressible layer of material. A set of plates covers the second layer and...     

A material 11 is protected from acoustic shock waves generated by impacting projectiles by means of a backing 12. Backing 12 has an acoustic impedance that efficiently couples the acoustic energy out of the material 11.

An annular acoustic liner for gas turbine engine ducts comprising Helmholtz resonator chambers wherein the resonator's turnable neck length and chamber depth lie on a surface which is concentric to the liner centerline. In another embodiment of the invention the liner is generally rectangular and the...     

An improved acoustic baffle for use with underwater hydrophone or acoustic transducer equipment on submarines and the like for attenuating acoustic energy of a noise character emanating from the submarine carrying the hydrophone equipment thereby rendering the hydrophone immune to undesired ambient noise...     

The present invention relates to an acoustical diffusor device which is made up of a plurality of specially designed and shaped cinder or concrete blocks which may be assembled together through the use of mortar to provide a diffusor of desired shape and configuration. Each diffusor includes a plurality...     

An acoustic liner comprising a sound permeable inside plate forming a first closed annulus, and a sound impermeable outside plate forming a second closed annulus located outside of and extending around the first closed annulus. The inside and outside plates are spaced apart and thus form an annular chamber...     

This invention relates to an acoustic board and in particular to one which includes a framework, a front panel formed with a plurality of openings and fitted on one side of the framework, a rear panel fitted on the other side of the framework thereby forming a space between the front panel and the rear...     

An acoustic liner comprising a sound permeable inside plate forming a first closed annulus, and a sound impermeable outside plate forming a second closed annulus located outside of and extending around the first closed annulus. The inside and outside plates are spaced apart and thus form an annular chamber...     

Apparatus for reducing acoustic transmission from mechanical or acoustic sources by means of a double wall partition, within which an acoustic pressure field is generated by at least one secondary acoustic source. The secondary acoustic source is advantageously placed within the partition, around its...     

An acoustic liner comprising a sound permeable inside plate forming a first closed annulus, and a sound impermeable outside plate forming a second closed annulus located outside of and extending around the first closed annulus. The inside and outside plates are spaced apart and thus form an annular chamber...     

The present invention relates to an acoustical diffusor device which is made up of a plurality of specially designed and shaped cinder or concrete blocks which may be assembled together through the use of mortar to provide a diffusor of desired shape and configuration. Each diffusor includes a plurality...     

An acoustic construction panel for use in the construction of walls, floors, or ceiling structures to improve the acoustical properties thereof, and a method of making that panel. The panel comprises a composition of natural wood fibers, paper and starch, and is absent of any chemical toxic products....     

An apparatus for preventing the transmission of sound in an underwater medium. A resilient housing encloses at least two voids. A first void contains a compliant tube consisting of two T-shaped support structures, each T-shaped support structure supporting a free-bending span designed to resonate at...     

A glazing panel and hollow glazing panel, the hollow glazing panel including a first pane, a second pane held in spaced-apart, face-to-face relationship with the first pane, and a plurality of localized damping members positioned between the first and second panes, adherent thereto, and distributed therebetween...     

A two-dimensional sound diffusor is composed of a plurality of wells defined by a matrix of projecting elements. The wells, which have different depths and widths, are arranged in a repeating pattern. The boundaries of the wells and of the repeating pattern are defined by projections arranged on a base....     

A noise reducing apparatus comprising a first passageway group consisting of a plurality of first passageways aligned in parallel with each other for forming a first flat wave A by sound waves having a first same phase passed through each first passageway from a sound source, and a second passageway...     

An acoustic attenuating liner has a non-metallic honeycomb core bonded on a backsheet. A corrosion-insulated perforated sheet is bonded to the honeycomb core by adhesive between the perforated sheet and the core. The mesh is woven to a plurality of different determined weave patterns from material on...     

This invention relates to an acoustic board and in particular to one which includes a framework, a front panel formed with a plurality of larger openings and smaller openings and fitted on one side of the framework, a rear panel fitted on another side of said framework thereby forming a space between...     

An acoustic/shock wave attenuating assembly comprised of porous screens forms an enclosure filled with a suitable pressure wave attenuating medium or material having fluid characteristics. This basic configuration can be suspended or held in place by a rigid structure. When the pressure attenuating medium...