Abstract: A noise suppressor for an apparatus having a cooling fan and cooling duct includes a muffler including a reflection plate for reflecting sound from the cooling fan, the reflection plate being provided at a position in the cooling duct confronting the intake plane of the cooling fan and formed substantially parallel to the intake plane. A sound-absorbing part of the muffler is provided on the reflection plate, and a distance d between the reflection plate and the intake plane is set such that d<c/(2×f) where f is the sound-absorption frequency of the muffler and c is the speed of sound.

Abstract: A method of forming a box-like acoustical substrate is provided. Portions of an acoustical substrate having a decorative surface are compressed to form a flange, a first compressed region, a second compressed region, and a third compressed region. First, second, central, and third uncompressed regions are positioned respectively adjacent to the compressed regions. A left first surface and a right first surface of the acoustical substrate may be folded toward the back surface of the substrate until the second compressed region and the third compressed regions are flush with the central uncompressed region. An outer portion of the left surface may then be folded towards the back surface until the flange is flush with the right edge. The acoustical product may be used as an acoustical trap or duct. When the acoustical product is utilized as a duct, an air impermeable sheet may be positioned on the external surface.

Abstract: An elevator installation includes an elevator car that moves in an elevator shaft with shaft doors and which car has at least one car apron arranged parallel to a plane of a shaft wall at a shaft door side. A device for reducing noises generated by the air flow arising between the shaft wall and the car apron includes sound-absorbing material that is mounted at the car apron and at the shaft wall.

Abstract: The present invention is an acoustic cabinet for the storage of musical instruments. Acoustic cabinet can have a storage portion having a plurality of individual storage units contained therein. One or more grill doors can cover the open end of acoustic cabinet. The size, shape, and arrangement of grill bars of door can be configured to reduce the effect of resonance. Rear panel of acoustic cabinet can include one or more sound-absorbing panels that absorb sound as it passes through acoustic cabinet. A protective backing can also be disposed between sound-absorbing panels and individual storage spaces to protect the panels from damage when instruments and other objects are inserted into the storage spaces. A combination of a grill door and sound-absorbing panels can allow acoustic cabinet to have a net-absorptive effect on a rehearsal room. One or more acoustic cabinets can be strategically positioned throughout a rehearsal room for optimal acoustic performance.

Abstract: An extended bandwidth folded well diffusor extends the diffusion bandwidth of a shallow, asymmetric diffusor by incorporating maximum-depth, folded L-shaped, half-width wells on both ends (sides) of a diffusor, thus providing increased maximum well depth without increasing the physical depth of the diffusor. When the inventive diffusor is placed in an array, the folded L-shaped, maximum-depth, half-width end wells form a novel T-shape, which offers a favorable impedance lowering the resonant frequency, thus extending the diffusor diffusion bandwidth. T-shaped recesses may also be located within a single diffusor. The front surface of the diffusor may be flat or curved or angled.

Abstract: An ultra light, noise reducing composite (1) comprises an acoustically transparent, light weight film (6) between an underlay layer (5) and an air flow resistance layer (4). This composite allows to easily tune the acoustic properties by balancing the absorption and sound transmission behaviour of the composite (1). This air flow resistance layer (4) has an air flow resistance of between 500 Ns/m3 and 10,000 Ns/m3 and an area mass between 200 g/m2 and 3,000 g/m2. The underlay layer (5) has a stiffness value in the range between 100 Pa and 100,000 Pa. The light weight film (6) may consist of a synthetic foil and preferably has a thickness of 0.01 mm.

Abstract: An integrated noise suppression acoustic panel includes a back plate, a face plate, and a bulk foam absorber disposed between the back plate and the face plate. The bulk foam absorber is formed of a thermoset material, such as bismaleimide or phenolic, and is manufactured using a low pressure process. In particular, a foamable material is melted, and a blowing agent is mixed with the foamable material to obtain a mixture. The foam is formed and the mixture is cured by heating it to a temperature, and maintaining the mixture at the temperature for a time sufficient to cure the mixture.

Abstract: A multi-layered fiber reinforced thermoplastic sound absorbing panel includes a porous fiber reinforced thermoplastic core layer having a first surface and a second surface, and includes a thermoplastic material and from about 20 weight percent to about 80 weight percent fibers, a tie layer covering the second surface of the core layer and including a thermoplastic material, and a barrier layer covering the tie layer. The barrier layer includes a thermoplastic material having a melting temperature higher than the melting temperature of the core layer thermoplastic material. The tie layer bonds the barrier layer to the core layer. The panel also includes a non-woven layer including a fabric bonded to the barrier layer. The non-woven layer forms an outer surface of the panel.

Abstract: A deformation and weather resistant, noise attenuating fencing assembly comprises a series of hollow posts, each post formed of a fiberglass reinforced resin, having spaced apart load bearing walls defining an exterior surface, an interior surface, a first open end and a second open end. The structure-reinforcing cap is inserted within a first open end of each of the posts and frictionally engages the interior surface of the post to substantially prevent movement of the exterior surface thereof when various types of appurtenant structures are mounted thereon, which would otherwise cause deformation and possible structural failure of the post walls. First and second clips are inserted into the first and second open ends of the post, respectively, to provide an easy mechanism to properly space and secure the posts together.

Abstract: A device including a membrane having first and second faces; a first substrate disposed on the first face of the membrane and having (i) a plurality of first absorptive regions and (ii) a plurality of first reflective regions formed as wells in a face of the first substrate, the first absorptive regions and the first reflective regions arranged in a pre-defined grid pattern; a second substrate disposed on the second face of the membrane and having (i) a plurality of second absorptive regions and (ii) a plurality of second reflective regions formed as second wells in a face of the second substrate, the second absorptive regions and the second reflective regions arranged in the pre-defined grid pattern.

Abstract: A floor covering characterized as having a strong noise-reducing properties for the interior trim of means of transport. The floor covering has, on the passenger side, a textile or non-textile surface, acoustically coupled through at least one microperforated sheet to a fibrous non-woven and/or foamed plastic. A microperforated sheet having a hole diameter from 0.2 to 0.5 mm and an interhole distance from 3 to 7 mm.

Abstract: The present invention provides means of enhancing the acoustic attenuation and vibration damping of a material by (1) embedding a plurality of small particles of either a high characteristic acoustic impedance or a low characteristic acoustic impedance or combinations of high and low characteristic acoustic impedance materials to form a matrix material to act as a acoustic attenuator or vibration damper; and (2) combing this matrix material with a second layer of a decoupling material that serves to effectively isolate the matrix material and reduce its tendency to vibrate sympathetically to the impinging acoustic energy. The mass of the resultant material may be very low while retaining excellent acoustic attenuation, vibration damping, and structural characteristics.

Abstract: The invention relates to an enclosure with a substantial rectangular configuration, adapted to contain an apparatus sensitive to acoustic vibrations, the enclosure comprising walls and acoustic damping material located within the wall, wherein the acoustic damping material comprises at least one absorbing body of acoustic energy absorbing material located adjacent to a rib of the enclosure. The acoustic vibrations most disturbing the processes in the apparatus within the enclosure are caused by standing acoustic waves within the enclosure with frequencies in the range between 50 Hz and 1000 Hz. These acoustic waves are efficiently damped by the provision of a block of acoustic absorbing material adjacent to one of the ribs of the enclosure, to such an extent that the need for thick walls of the enclosure is substantially obviated, leading to a less voluminous enclosure.

Abstract: A thermoformable acoustic sheet formed by a compressed fibrous web including high melt and adhesive thermoplastic fibres in which the adhesive fibres are at least partially melted so that in the compressed web the adhesive fibres at least partially coat the high melt fibres and reduce the interstitial space in the fibre matrix. Also included is a method of producing a thermoformable acoustic sheet which includes the steps of heating a fibre web including high melt and adhesive thermoplastic fibres to at least partially melt the adhesive fibres and compressing the web to form a sheet so that the adhesive fibres at least partially coat the high melt fibres to reduce the interstitial space in the fibre matrix.

Abstract: A composite material containing inclusions of spherical shells in which each spherical shell encapsulates a rubber core with ferrite loading. The inclusions are embedded in a matrix material of syntactic foam. The spherical shells are made from glass and therefore acoustically transparent and in combination with the cores are statically stiffer than the surrounding matrix material. The composite material with the matrix material and inclusions allows the composite material to be acoustically dissipating with a stiffness in which the energy of forces associated with undersea platforms is resisted.

Abstract: A passive acoustic liner system (50) for attenuating a sound field comprising, in acoustic series, a mode-scattering segment (48) and a sound-absorbing segment (40), wherein the mode scattering segment (48) provides a reactance between ?12 and ?2 ?c and the sound absorbing segment (40) provides a reactance between ?1 and 0 ?c thereby providing a reactance discontinuity such that mode-scattering of the sound field enables the sound-absorbing segment (48) to further absorb the scattered sound.

Abstract: An acoustic barrier that achieves excellent noise insulating properties, and is relatively thin and relatively light in weight includes a flexible thermoplastic barrier layer having a plurality of apertures defining a latticed structure which includes apertures for pass-through components and non-pass-through apertures. The non-pass-through apertures are located where noise levels are expected or known to be relatively low. Effective acoustic performance can be maintained by completely eliminating material from the relatively thick and dense barrier layer at the low noise levels areas, and providing only absorptive decoupler material and/or lightweight sheet material such as plastic films in those areas.

Abstract: A vehicle trim panel including a structural frame portion having an inner surface for facing a vehicle body and an outer surface opposite the inner surface and a plurality of flexible projections extending from the inner surface of the structural frame portion and configured to contact the vehicle body to thereby reduce buzz, squeak, and rattle (BSR) between the trim panel and the vehicle body.

Abstract: A substrate for use in a flooring system which has a subfloor and a decorative upper layer. The substrate is made in a continuous sheet which has a bottom surface, a top surface, side surfaces and end surfaces. The top surface and the oppositely facing bottom surface are essentially parallel to each other and are spaced apart by the thickness of the substrate. Voids are provided in the substrate, the voids are provided between particles of rubber or other similar material. When the substrate is positioned between the subfloor and the decorative top layer, the particles of rubber provide the strength required to prevent deformation of the substrate in the direction of the thickness and the voids contribute to the sound dampening characteristics required to provide decibel reduction across the thickness of the substrate.

Abstract: A trim panel insulator is provided for a vehicle. The insulator includes a nonlaminate acoustical and thermal insulating layer of polymer fiber. The insulator may include a relatively high density, nonlaminate skin of polymer fiber and/or one or more facing layers constructed from various materials.

Abstract: The present invention provides a sound barrier 1 including a plurality of elongate panels 2 having first and second ends 3 and 4, each panel 2 being formed from a shell 5 defining an inner chamber 6 adapted to contain sound attenuating liquid, said plurality of panels 2 being supportable in a planar configuration by a first support means 7 adapted to engage said first and second ends 3 and 4 respectively. Preferably the shell 5 is constructed from plastic and/or fiberglass and the sound attenuating liquid is water which may optionally include other materials such as sand, slurry, concrete rubble, mud, etc. Some embodiments include second support means 9 which are attachable to the post 7 so as to engage the panels 2 and thereby transfer a, substantial portion, or all of, the weight of each panel 2 to the post 7.

Abstract: Sound radiating structure includes a plurality of pipes each defining an inner cavity along the length of the pipe. Each of the pipes has an end opening at one end and is closed at the other end with a closure. Each of the pipes also has a side opening in its one side portion. When a sound is input to the sound radiating structure, it re-radiates various sound waves through a number of the end and side openings together with reflected sound waves.

Abstract: A panel structure for a transport machine is disclosed which is constituted by an integral combination of an outer panel and an inner panel. The inner panel has reinforcing protuberances and recesses, possessing a higher rigidity than the outer panel. The protuberances of the inner panel and a back side of the outer panel are bonded together through insulating layers present on the protuberances.

Abstract: A honeycomb acoustic unit is provided, the unit comprising first and second honeycomb layers, the layers being made of honeycomb core, each being formed by metallurgical bonds, and a deformable septum having two opposing sides, the first and second honeycomb layers being metallurgically bonded to the two opposing sides of the deformable septum.

Abstract: A sound absorbing panel comprising a standoff layer disposed between a back plate and a screen. The standoff layer supports the screen at a standoff distance from the back plate. The standoff distance is substantially equal to ¼ the wavelength of a sound to be absorbed. An alternate embodiment sound absorbing panel includes a felt layer between the standoff layer and the screen. Another alternate embodiment comprises an apertured membrane supported by standoffs at a standoff distance from the back plate. The standoffs could be any appropriate standoff shape including I standoffs, Z standoffs, and angled standoffs. In one alternate embodiment the apertured membrane is a screen. In another alternate embodiment the apertured membrane is a perforated plate.

Abstract: The invention concerns a sound-proofing panel, in particular a rotorcraft structural or lining panel: the sound-proofing panel (1) comprises at least two opposite plates (2, 3, 5, 6) forming between them a closed internal space (4), and an aggregate (7) including at least solid elements (8) in contact and which fills entirely said internal space (4).

Abstract: An acoustic isolator is placeable between a sound producing body and a resting surface. The acoustic isolator includes a foam member having a first surface for receiving the sound producing body and a second surface for engaging the resting surface. The foam member is composed of a supportive foam member capable of substantially preventing the transfer of sound induced vibrations between the sound producing body and the resting surface while sustaining an internal deflection of less than about thirty percent.

Abstract: A sound absorptive multilayer composite having an air-impermeable barrier, an air-permeable reinforcing core having an airflow resistance of at least about 100 mks Rayls and a thickness at least about ⅔ the final composite thickness, and a semipermeable airflow-resistive decorative membrane having an airflow resistance of about 500 to about 4000 mks Rayls can provide improved acoustic performance while maintaining a low thickness.

Abstract: A portion of a chassis comprised of a material forming a portion of the exterior of the chassis and a high-density flexible material adjacent an inner surface of the portion of the chassis with air holes formed contiguously through both the portion of the chassis and the high-density flexible material.

Abstract: An exhaust system baffling apparatus is provided. The apparatus includes a tube with at least one end that is not open. The apparatus further includes a plurality of C-shaped flanges in surrounding relation about the tube. The outer edges of the flanges have a contour which generally corresponds to a contour of an inner surface of a wall of an exhaust pipe. Opposed portions of the flanges adjacent the slits of the flanges are spread apart along the tube in a longitudinal direction. In addition, the opposed portions of the flanges adjacent the slits are angled in opposite directions and extend radially from the tube at a non-perpendicular angle with respect to the tube. At least two of the flanges include brackets adjacent the outer edges of the flanges, wherein the brackets are adapted for securing the apparatus to an interior portion of the exhaust pipe.

Abstract: Structured pre-form bodies as panel lining for wide-band sound absorption are made of an open-cell foam material having a rigid framework co-vibrating in a resonant manner at low frequencies. The pre-form bodies have a base layer and a columnar structure positioned directly in front of or on the base layer. The columnar structure has a non-symmetrical distribution of height and cross-section, thereby forming a wide-band tuned moderator gap and the columnar height corresponds approximately to the density of the base layer. The columnar structure has a framework resonance adjustable as a function of parameters of the base layer.

Abstract: A multilayered, sound-insulating, mechanically strong sandwich element comprising two facing layers (1) substantially attached to a plastic foam core consisting of at least two layers (2) which are joined through contact points (also called bridges) (3) creating a gap or gaps (4) between the core layers (2), and in case of long spans and/or thin facing layers, travel stops inside the gap/gaps (4) to keep the core layers (2) at a certain distance from each other, wherein the core layer material is a semi-rigid, cellular material containing more tan 50 percent open cells, and has a tensile strength of more than 50 kPa, and has a compressive strength from 5 to 200 kPa, at 10 percent deformation. The distance between the contact points or bridges (3) is at least 350 mm. The new sandwich element can be used as a sound-insulating door, a partition element or a construction unit.

Abstract: The present invention provides a vibration dampening laminate that is lightweight and has superior sound insulation and vibration dampening properties. The vibration dampening laminate comprises a constraining layer, a viscoelastic adhesive layer, a foam spacing layer and a pressure sensitive adhesive layer including a release layer. The pressure sensitive adhesive layer and release layer are contoured to fit a profile of the article being soundproofed and vibration dampened.

Abstract: The present invention provides methods and apparatus for constructing an acoustic absorbing structure, such as a wall or enclosure, with removable and serviceable acoustic absorbing panels.

Abstract: An acoustic blanket system for use in attenuating acoustic energy. The acoustic blanket system including an acoustic blanket and apparatus for mounting the acoustic blanket to a structure. The acoustic blanket includes first and second cover materials heat-sealed around at least a portion of their perimeter. At least one acoustic attenuating panel is disposed within the heat-sealed cover materials to form a fully encapsulated acoustic blanket. The system for mounting the blanket includes a plurality of fastener assemblies that connect the blanket to a structure to define a tunable air gap of pre-determined dimension between the blanket and the structure. The mounting system also provides dimensional control of the blanket relative to the structure to control the air gap and prevent slumping and/or deformation during maximum loading environments.

Abstract: A sandwich material comprising two metal plates affixed to and separated by a fibrous core, is characterised in that the core comprises a three-dimensional porous network comprising metal fibres, wherein substantially all of the fibres are inclined at an acute angle to the plates. The sandwich material is lightweight, thin and handles like a monolithic sheet. It displays high beam stiffness and is easy to weld. It as therefore particularly useful in the manufacture of aircraft and vehicle parts.

Abstract: A sealing and acoustic insulation panel, in particular for automobile vehicle doors, includes a sealing sheet and a layer of acoustic insulation, with a bead of adhesive material on the sealing sheet for fixing the panel to a support plate. A frame for applying pressure to the bead of adhesive material is placed between the sealing and acoustic insulation panel and a trim panel clipped to the support plate.

Abstract: A multilayer product which comprises a first element consisting of a layer of spongy, semi-rigid polymer (A), impregnated on one or both sides with polyurethane resin (B), and inserted between two layers of glass fibre, natural fibre or a combination of glass fibre and natural fibre (C) coupled with the central layer (B) (A) (B), wherein the first element is coupled with at least a second element comprising a layer of spongy, semi-rigid polymer (A) , wherein the second element is impregnated on one or both sides with polyurethane resin (B), and wherein the second element is coupled with an additional layer of glass fibre, natural fibre or a combination of glass fibre and natural fibre (C).

Abstract: A double-walled damping structure includes two parallel face plates 1 and 2, a plurality of ribs 3 and 4 extending in the same direction to connect the two parallel face plates 1 and 2, wherein in a section taken perpendicularly to the direction of extension of the ribs 3 and 4, all or most of the holes defined by the adjacent two ribs and the face plates are trapezoidal. The structure less transmits vibration, and is capable of further increasing a damping effect when a damping material is attached.

Abstract: The present invention provides a surface material comprising a fibrous structure having a weight average single fiber thickness of from 0.0001 to 1 dtex, a thickness of from 0.10 to 5 mm and a unit weight of from 50 to 500 g/m2, and disposed on a surface of a body in order to convert at least a part of a surface wave, generated on the surface of the body by vibration of the body, into a vibration of the fibrous structure, and a method for suppressing the influence due to the surface wave. In the present invention, by disposing the surface material on surfaces of various members receiving vibration, a modulation of the vibration originating from the surface wave which greatly influences a human acoustic sense can be efficiently suppressed, and a sound quality and an image quality can be prevented from being deteriorated.

Abstract: In a sound-deadened wall comprising wooden studs, each of which has a front edge and a back edge, a front wall panel is fastened to the front edges of the studs and a back wall panel is fastened to the back edges of the studs. Further, front spacers are positioned along the front edge of each stud, between the front edge of said stud and the front wall panel, so as to define air gaps between the front edge of said stud and the front wall panel, and back spacers are positioned along the back edge of each stud, between the back edge of said stud and the back wall panel, so as to define air gaps between the back edge of said stud and the back wall panel. Each wall panel has two expansive surfaces and the associated spacers are defined by elastomeric strips adhering to such wall panel, on the expansive face to face the associated edges of the studs, before such wall panel is fastened to the associated edges of the studs.

Abstract: The invention relates to an acoustic insulating glazing unit. This glazing unit comprises two glass sheets (12, 14) joined together around their periphery by means of an assembly (16) forming a seal (163) and an insert frame (161) which defines, with the two glass sheets, a flat cavity filled with a gas, and a waveguide fastened between the glass sheets, internal to the insert frame. The waveguide consists of at least one straight tubular section (20, 22, 24, 26) placed on the periphery of the gas-filled cavity along one side of the glazing unit, this section being provided with a transverse partition (28) which closes the latter in its length direction, the said partition being placed at a length position along the section which depends on the acoustic mode of the cavity that it is desired to disorganize, this partition defining, on either side of it, two chambers (30, 31) which communicate with the cavity through the ends of the sections.

Abstract: A soundproofing cover absorbs noises, produced by a vehicle. It is fastened to a plurality of vehicle-side installation portions, and includes a cover body, composed of a polymer foamed substance, and a plurality of brackets, held integrally to the cover body. The respective brackets have an installation portion and a holding portion. The installation portion is to be fastened to the vehicle-side installation portions. The holding portion is held and fastened integrally to the cover body. At least two of the installation portions constitute a datum bracket, connected by one of the holding portions shared commonly. The positioning accuracy can be improved in the installation of the soundproofing cover to the vehicle-side installation portions so that the installation operability can be upgraded. In addition, the increment of the weight can be kept minimum so that the lightweighting requirement can be satisfied.

Abstract: The present invention provides for an acoustically absorbent porous panel that is both rigid and resistant to sagging caused by moisture. The acoustically absorbent porous panel is comprised of at least two layers. The first layer is a facing layer formed from a cured aqueous foamed cementitious material. The foamed cementitious material comprises on a wet basis about 53% to about 68% by weight cement, about 17% to about 48% by weight water, about 0.05% to about 5% by weight fiber, and about 0.01% to about 10% by weight surfactant. Additionally, pores distributed within the cured material comprising about 75% to about 95% by volume of the material. The second layer is a backing layer that is affixed to the facing layer.

Abstract: A process for producing an acoustically resistive layer, particularly for the nacelles of aircraft jet engines. The process includes producing a structural component by using thermoplastic resins, this component having a given quantity of open surface relative to the acoustic waves to be treated. The structural component is connected to an acoustic metallic fabric having a mesh adapted to the open surface quantity of the structural component. Then, the thermoplastic resin is heated under pressure at high temperature.

Abstract: A soundproofing system is used to insulate sound producing devices or parts of systems, especially vibrating conveyers. Such a system includes insulating elements that are provided with an inner face in the direction of the sound source and an outer face in the direction away from the sound source. A sound absorbing membrane which is made of a textile material and, more particularly, at least partially consists of glass fiber threads and/or woven wire, is arranged in the region of the inner face. The sound absorbing membrane is the inner skin of a covering. The covering includes an outer skin made of textile material. A soft insulating material comprising fiber mat material is arranged together with solid flat material in between the inner and outer skin of the covering. The insulating element offers optimal usage of all three elements, i.e., damping diaphragm, insulating material and at least one reflecting surface on the solid flat material.

Abstract: Shaped, microperforated sound absorbers and methods of making the same are herein provided. In one embodiment, the sound absorber is produced from a polymeric, typically plastic, film having a series of microperforations formed over all or a portion of the film surface. The film is then formed to produce the desired three-dimensional shape. The depth of the three-dimensional shape is controlled to provide the desired cavity depth which, in turn, influences the sound absorption spectrum. After forming, the three-dimensional shape is maintained without the need for additional supports or frames. Deformation of the microperforations due to the forming process does not substantially interfere with the sound absorption properties of the film. Further, film resonance over largely unsupported portions also has little effect on the sound absorption spectrum.

Abstract: Aerogel particles, in particular in the form of composite materials, are used to deaden structure-borne and/or impact sounds.

Abstract: An acoustical panel formed from a fibrous, open-celled material comprised of up to about 50% by weight fibers, between about 3% and about 10% by weight binder, between about 20% and about 75% by weight filler and about 0.01% to about 2.0% by weight surfactant. Additionally, voids are formed within the panel having an average distribution size diameter of about 50 &mgr;m to about 250 &mgr;m. The acoustic panel achieves very high sound absorption properties without the need for additional surface perforations, while maintaining a very high surface hardness.

Abstract: A sink, and a method of reducing vibration and resulting noise of such sinks, are disclosed. The sink includes a basin, a drain and first and second pads. The basin has a bottom wall, side walls, and inner and outer surfaces of such walls. The drain is in the bottom of the basin, and first and second regions are defined between the drain orifice and the first and second sides, respectively. The pads are attached to the bottom and a side wall, in each case proximate respective midpoints of open regions thereon. The pads are a laminate of a rubber-like material and metal.