Abstract: A filter bank is provided. The filter bank includes a housing having a front face and a back face. Air flows along an air flow path from the front face to the back face. A filter layer is held in the housing. The filter layer is oriented between the front and back faces such that air flows through the filter layer before discharging from the back face. An attenuation layer is positioned within the housing to attenuate sound as the sound propagates between the front and back faces. The attenuation layer is oriented to extend along the air flow direction.

Abstract: A noise control system is operable within a box-like structure provided by the dual bulkhead plenum of the vehicle dashboard positioned within the transfer path along which the noise is being transmitted from the source of the generated noise to the receiver of the noise in the passenger compartment of an automobile. The plenum is divided into discrete chambers into each of which is provided a counter noise generating apparatus to create a counteracting noise offsetting the noise generated at the source. The acoustic resonance of the chambers amplifies the noise control energy. The geometry of the individual chambers can be varied to optimize the packaging and sound control or shaping strategy. The sound energy permitted to pass through the plenum to the driver's side of the passenger compartment can be tuned to be different than the noise received in the passenger's side.

Abstract: An exemplary embodiment of the present invention provides a silencer. The silencer includes an enclosure with a first airflow path configured to allow air to pass through the enclosure and attenuate noise entering the enclosure. The enclosure also includes an opening configured to provide a second airflow path if the first airflow path is obstructed.

Abstract: The present invention provides methods and devices for the abatement of noise emanating from surgically created abdominal stomas. In one embodiment, the present invention provides a sound abatement device for an abdominal stoma. The device includes a noise suppressor formed of sound dampening material, which defines an opening and cavity suitable in size and shape for receiving and enveloping a stoma formed through a body wall of an individual. The device further includes a support arm extending from the noise suppressor, which includes a first end connected to the noise suppressor and a second end disposed opposite thereof. The device further includes a base member disposed proximate the second end of the support arm, which includes an attachment for connection to an individual. The device also includes an attachment feature for releasable attachment of the second end of the support arm to the base.

Abstract: In a method for adjusting a Helmholtz resonator (10), in which a resonator volume (11) is connected to a space (13) to be provided with damping along an axis (29) via a constriction (12) having an acoustic impedance, the acoustic impedance of the constriction (12) is altered in order to adjust the Helmholtz resonator (10).

Abstract: The invention relates to a multilayered acoustically and thermally effective insulation having a defined layer structure, especially for internal combustion engines of motor vehicles.

Abstract: A process for the production of an acoustically resistive structure that can be inserted in an alveolar structure so as to obtain a coating for the acoustic treatment, whereby the acoustically resistive structure includes at least one porous layer (34) and at least one reinforcement structure (36) assembled by gluing, the process including: applying an amorphous-type adhesive on the at least one reinforcement structure (36), perforating or micro-perforating the reinforcement structure (36) after the application of the amorphous-type adhesive, and applying the at least one porous layer against the face of the reinforcement structure (36) that is coated with amorphous-type adhesive.

Abstract: A multilayer sound absorbing structure, comprising a first microperforated film, a mesh layer and a second microperforated film disposed in this order is provided.

Abstract: Method for producing a stationary wave field of arbitrary shape comprising the steps of defining at least one volume being limited in the direction of the axis of propagation of a beam, of the type 0?z?L; defining an intensity pattern within the said region 0?z?L by a function F(z), describing the said localized and stationary intensity pattern, which is approximated by means of a Fourier expansion or by a similar expansion in terms of (trigonometric) orthogonal functions; providing a generic superposition of Bessel or other beams highly transversally confined; calculating the maximum number of superimposed Bessel beams the amplitudes, the phase velocities and the relative phases of each Bessel beam of the superposition, and the transverse and longitudinal wavenumbers of each Bessel beam of the superposition.

Abstract: A multilayer sound absorbing sheet including a film layer having through-micro bores and apertures, and a fibrous material layer disposed on the film layer is provided. A method of absorbing sound including providing the multilayer sound absorbing sheet of the present disclosure and positioning the multilayer sound absorbing sheet between an acoustic source and a sound-reflecting surface is also provided.

Abstract: A sound barrier and method of sound insulation are disclosed. In one aspect of the disclosure, a sound barrier comprises a first, solid medium, such as a viscoelastic solid and a second medium, such as air. At least one of the two media forms a periodic array disposed in the other medium. The solid medium has a speed of propagation of longitudinal sound wave and a speed of propagation of transverse sound wave, the speed of propagation of longitudinal sound wave being at least about 30 times the speed of propagation of transverse sound wave.

Abstract: A method and apparatus for the reduction of sound travelling in a wave-guide in the air above the ground is presented, comprising the provision below the ground of at least a top layer which, at the interface of the top layer and air, has an acoustic impedance which substantially matches the acoustic impedance of the air. Also a cylindrical structure with holes can be used. The method and apparatus may be used for the reduction of aircraft sounds, especially in the range of 15 Hz to 40 Hz, during the first part of take-off, wherein said layer(s) below the ground are provided in a range starting at a lateral side of the runway and extending until at least 100 meters, preferably until at least 300 meters and more preferably until at least 500 meters, from the runway.

Abstract: A laminated sheet metal is comprised of a first sheet of metal and a second sheet of metal that are adhered together by a polymer layer core that is interposed between the two sheets and provides visco-elastic adhesion. The polymer layer has at least one region of a first polymer material that is selected for optimal viscous and elastic qualities by which to dampen the transmission of noise and vibration between the sheets, and at least one other region of a second polymer material that is selected for optimal adhesive qualities by which the sheets are optimally joined together against delamination. Thus the laminated sheet metal can be tailored to optimize the qualities that are desired for the manufacture of a particular product.

Abstract: The present invention relates to an acoustic attenuation device for an intake line of an internal combustion engine and to an intake line such as this incorporating same. An acoustic attenuation device according to the invention is intended to have a flow of pressurized gaseous fluid passing through it and comprises: a conduit structure which has a tubular wall ending in two ends, these respectively being the fluid inlet and fluid outlet ends, which are able to be incorporated into the intake line, and at least one resonance chamber which is arranged on the outside of this structure and which communicates therewith via at least one opening formed in said wall, the or each chamber being axially delimited by two transverse partitions.

Abstract: A noise attenuation device for use in a jet engine test cell for testing a jet engine comprising a carbon steel pipe which is aligned axially with direction of exhaust from the jet engine. The carbon steel pipe is positioned within an augmenter within the test cell. Cold air enters the front end of the carbon-steel pipe. Adding three times the mass of cold air to that of the hot jet exhaust allows the hot jet exhaust to mix with the cold air forming an engine exhaust-cool air mixture. When the engine exhaust-cool air mixture reaches the outlet end of the carbon steel pipe, its temperature is reduced from 3800° F. to less than 1200° F., which substantially reduces noise generated by the jet exhaust. Located in proximity to the rear end of the carbon steel pipe is an annular region which is formed between perforated side plates within the carbon steel pipe and the inner wall of the augmenter. The flow is diffused as the flow area expands in the annular region.

Abstract: An acoustic composite comprises a flow resistive substrate having a solid acoustic barrier material bonded to at least a portion of a major surface of the flow resistive substrate; wherein the acoustic barrier material has a density greater than about 1 g/cm3 and the acoustic composite has a porosity between about 0.002% and about 50%.

Abstract: A region of air is manipulated to reflect, absorb, or redirect sound energy to prevent the sound energy from reaching a listener separated from the sound source by the region of air. The region of air may be manipulated by directing ultrasonic sound waves with a sound pressure level of at least 140 decibels at the region of air.

Abstract: Disclosed are apparatus and methodology for reducing noise and wear in a flapper configured exhaust tip for a marine exhaust system. A metallic flapper is located at an end portion of an exhaust tip of the exhaust pipe. An elastomeric flapper assembly is provided covering the exhaust tip and includes a lip portion configured to provide noise reduction by functioning as a stop for a tip portion of the metallic flapper. The metallic flapper is positioned such that a tip thereof contacts the elastomeric flapper assembly rather than the metallic exhaust pipe. Such contact with an elastomeric flapper assembly reduces noise previously produced by flapper contact with the hot exhaust pipe.

Abstract: A sound insulation process comprises (a) providing at least one sound barrier comprising at least one composite resonator element; and (b) placing the at least one sound barrier in at least one gas stream that is at least partially enclosed.

Abstract: A sound barrier comprises a substantially periodic array of structures disposed in a first medium having a first density, the structures being made of a second medium having a second density different from the first density, wherein one of the first and second media is a viscoelastic medium having a speed of propagation of longitudinal sound wave and a speed of propagation of transverse sound wave, the speed of propagation of longitudinal sound wave being at least about 30 times the speed of propagation of transverse sound wave, and wherein the other of the first and second media is a viscoelastic or elastic medium.

Abstract: A method of forming a panel constrained layer damper treatment from a laminate, having a panel and a visco-elastic layer attached thereto, by forming a panel constrained layer damper from the laminate to a predetermined shape is provided. Additionally, the method of the present invention includes attaching the panel constrained layer damper to a substrate to form the panel constrained layer damper treatment. The method may also include subjecting the panel constrained layer damper to heat energy to bond the visco-elastic layer to the substrate. In addition, various methods of attaching the panel constrained layer damper to the substrate are provided.

Abstract: A golf club head with sound tuning composite members forming at least a portion of the surface of the golf club head is disclosed herein. The composite members being a composite layer made out of a sandwiched core layer that is interposed inside the midsection of the composite member to provide vibration damping and sound tuning characteristics.

Abstract: A layout structure and a method for reducing audible noise generated by a flexible printed circuit are provided. The layout structure includes a flexible printed circuit and a piezoelectric element. The flexible printed circuit is disposed with respect to an axis. When an alternating voltage/current is applied across the piezoelectric element, the piezoelectric element expands and contracts alternately. The piezoelectric element is located on the flexible printed circuit, and an angle between the axis and a side of the piezoelectric element is less than 90 degrees.

Abstract: An apparatus and method for reducing noise in a vehicle having a soft top roof. The apparatus includes a main extension bar having a first end and an opposing second end. A first coupling mechanism is affixed to the first end and a second coupling mechanism is affixed to the second end. The first and second coupling mechanisms are attached to roll bars located on a top portion of the vehicle. With the apparatus in place upon the roll bars, the main extension bar exerts upward force against the soft top roof of the vehicle, thereby reducing movement of the soft top roof and noise within the interior of the vehicle.

Abstract: Disclosed are apparatus and methodology for reducing noise and wear in a flapper configured exhaust tip for a marine exhaust system. A flapper, normally located within an exhaust tip of a marine exhaust system, is relocated upstream of the point in the exhaust system where cooling water normally contacts the exhaust pipe. An exhaust tip is coupled to the upstream portion of the exhaust system by way of an elastomeric coupling device. The flapper is positioned such that a tip thereof contacts the elastomeric coupling rather than the metallic exhaust pipe. Such contact with an elastomeric coupling device reduces noise previously produced by flapper contact with the hot exhaust pipe occasioned by destruction and/or heat degeneration of elastomeric material generally associated with the flapper device.

Abstract: An air filter system for an internal combustion engine of a vehicle can have an indicator for signaling restricted flow of air through a replaceable air filter member mounted to a filter assembly. At least one sidewall can be associated with the replaceable air filter member to be positioned with an air stream passing through the air filter member. A resettable air filter status indicator can provide a visually perceivable signal external of the filter assembly. The resettable air filter status indicator can be integrally formed in the sidewall for indicating if a mounted air filter member requires replacement in response to air intake differential pressure with respect to atmospheric pressure on a downstream side of air flow through the replaceable filter member being above a predetermined threshold value.

Abstract: Method for influencing noise, wherein a noise source (16), in particular an engine in a motor vehicle, generates the noise with a substantially periodically variable excitation, and wherein a reference variable which is characteristic of the noise source, in particular an engine speed, is present at predetermined successive supply instants (ti), comprising the method steps; reading out at least a first value (Ni?1) of the reference variable at a first supply instant (ti?1) and a second predetermined value at a second supply instant (ti); generating the reference signal (12) at least one instant (t) between the second supply instant (ti) and a third supply instant (ti+1) as a function of the first and second values that were read out; and sending the reference signal (12) to a device for actively influencing noise (11), which generates activation signals (13) for at least one actuator (14) as a function of the reference signal (12), wherein the at least one actuator (14) emits compensation sound, which interfe

Abstract: An example liner assembly includes a backing plate that supports a cellular structure covered by a perforated face sheet including a plurality of openings. Each of the plurality of openings is of a size determined to provide desired acoustic performance.

Abstract: An acoustical panel includes an acoustical layer having an interlocking matrix of calcium sulfate dihydrate, polyethylene glycol and at least one of the group fibers, a lightweight aggregate and mixtures thereof. The acoustical layer has voids in the interlocking matrix that are configured to absorb sound. The polyethylene glycol is selected to agglomerate dust at temperatures generated by friction when the panel is cut. A method of making the acoustical panel includes making a slurry comprising calcium sulfate hemihydrate, polyethylene glycol, water and at least one of the group consisting of a lightweight aggregate, fibers and combinations thereof. Foam is added to the slurry, preferably at the mixer discharge. A continuous strip of acoustical layer material is formed from the slurry. The acoustical panels are formed by cutting the strip into individual panels. Finally, the partially hydrated calcium sulfate hemihydrate is allowed to fully set.

Abstract: An inlet door assembly and method for reducing noise from an auxiliary power unit (APU) contained within an aircraft housing is provided. The inlet assembly includes an inlet duct, an actuator, and a door. The inlet duct is configured to extend from the auxiliary power unit to the aircraft housing and has a sidewall that defines a flow passage through which APU noise propagates. The actuator is disposed at least partially within the inlet duct. The door coupled to the actuator. The actuator is also configured to selectively rotate the door between at least a first position, in which at least a portion of the door deflects APU noise in a first direction, and a second position, in which at least a portion of the door deflects the APU noise in a second direction.

Abstract: Acoustic mats include a face layer and an absorptive layer having first and second surfaces wherein the second surface of the absorptive layer may be secured to said face layer. The mat further includes a plurality of discrete segments secured to the first surface of the absorptive layer such that regions of the first surface of the absorptive layer may be exposed, thereby allowing sound to pass between adjacent discrete segments into the absorptive layer.

Abstract: A method for optimizing sound and vibration comfort in a mobile passenger compartment, the method applied by a design team to carry out overall design of the passenger compartment and/or by at least one equipment supplier to carry out design of a portion of the passenger compartment. The method establishes target values to be achieved for well-identified comfort indices, defines requirements and input data relating to plural equipment suppliers to obtain a totality of information relating to the passenger compartment, estimates values of the comfort indices and compares them with the target values, and then modifies individually or in combination the input data to correlate them with the target values.

Abstract: A noise absorbing structure of an instrument panel of a vehicle includes a first noise absorbing panel, provided in the instrument panel disposed in front of a driver seat of the vehicle, a second noise absorbing panel, provided in the instrument panel disposed in front of a front passenger seat of the vehicle, and a third noise absorbing panel, provided in the instrument panel that is disposed in front of a moisture removing ventilation port.

Abstract: An elevator cab ceiling (22) includes an upper ceiling panel (26), a lower ceiling panel (28), and a ventilation channel (30) extending between the upper ceiling panel (26) and the lower ceiling panel (28). The ventilation channel (30) extends at an oblique angle relative to the upper ceiling panel (26) and separates space between the upper (26) and lower (28) ceiling panels into an upper cavity (32) and a lower cavity (34). A plurality of partitions (36) are formed within at least one of the upper (32) or lower (34) cavities. In one example, an acoustically resistive element (42) extends at least partially along a portion of the ventilation channel (30). The plurality of partitions (36) and the acoustically resistive element (42) cooperate to reduce noise levels transmitted into an elevator cab (10) via the ventilation channel (30).

Abstract: A soundproofing material for vehicle having a laminated structure comprising two sound absorbing layers and an interlayer interposed therebetween, characterized in that the interlayer is formed by bonding and laminating on the respective side of an air-impermeable film made of a thermoplastic resin film having a thickness of from 7? to 50? heat-fusible films having a thickness of from 7? to 50? made of a thermoplastic resin film having a lower melting point than that of the air-impermeable film using a multi-layer inflation method and the soundproofing material is heat pressure-molded so that the heat-fusible film is melted to cause the sound absorbing layers to be bonded to the respective side of the air-impermeable film.

Abstract: A system for the noise reduction of wind turbines comprises at least one acoustic sensor provided at the wind turbine, a detection unit and a control unit, wherein said detection unit is adapted to detect tonal components in a signal of said sensor, and wherein said control unit is adapted to control wind turbine operating parameters in dependence of an amplitude of a tonal component.

Abstract: A high-efficiency, frequency-tunable, acoustic wool, includes a multiplicity of randomly-arrayed, continuous fibers. The fibers have segments differing in at least one physical parameter for attenuating acoustic vibrations. A method of attenuating acoustic vibrations includes providing continuous fibers having segments differing in at least one physical parameter. A multiplicity of the fibers are randomly arrayed into an acoustic wool.

Abstract: An acoustical panel comprising a continuous phase of an interlocking set gypsum matrix and a method of preparing an acoustical panel are disclosed.

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 is employed to attenuate ultrasonic noise propagating in a flow stream of a fluid flow system. In particular, the method attenuates the noise propagating between a noise source and a reference point in the flow stream (wherein the reference point and the noise source are positioned in the flow stream in direct acoustic line of sight relation). The method includes positioning an absorbent element in the flow stream between the noise source and the reference point. Then, the ultrasonic noise is directed past vicinity of the absorbent element such that indirect ultrasonic noise is absorbed by the absorbent element. Preferably, the method also includes deflecting the ultrasonic noise to convert direct noise to indirect noise prior to directing the ultrasonic noise past the vicinity of the absorbent material in the flow stream. Such a method may be employed to attenuate ultrasonic noise by up to about 20 dB to 45 dB.

Abstract: An applicator head for connection to a robotic device, and useful for applying a fluid material to a substrate. The applicator head comprises: (a) a body portion; (b) at least one material delivery system comprising an inlet, a fluid delivery cavity, and two or more passageways connecting the inlet to the fluid delivery cavity; and (c) a nozzle plate attached to the bottom surface of the body portion, and having a plurality of openings communicating with the fluid delivery cavity. In one embodiment, the applicator head comprises a nozzle inserted in each of the plurality of openings in the nozzle plate, with each nozzle adapted to apply a bead of a fluid material to a substrate, with the beads spaced less than about 2 mm apart. Also disclosed is a sound-damping composition comprising: (a) n-butyl acrylate-acrylonitrile-styrene copolymer; (b) at least about 0.

Abstract: A system (400) for reducing non-acoustic noise includes a primary sensor (420), at least one secondary sensor (410), a filter (415), and a summation unit (425). The primary sensor (420) measures pressure and produces a primary pressure signal. The at least one secondary sensor (410) measures pressure and produce a secondary pressure signal. The filter (415) processes the secondary pressure signal to produce a filtered pressure signal. The summation unit (425) subtracts the filtered pressure signal from the primary pressure signal to reduce non-acoustic noise in the primary pressure signal.

Abstract: The present invention relates to a sound absorber consisting of a first non-woven fabric facing towards the sound-emitting source having a layer thickness within a range of from 2 to 15 mm, a density within a range of from 50 to 500 kg/m3, a weight per surface area within a range of from 0.1 to 2.5 kg/m2, and a flow resistance within a range of from 50 to 1000 kNs/m4, and a second non-woven fabric facing away from the sound-emitting source has a layer thickness within a range of from 10 to 28 mm, a density within a range of from 20 to 100 kg/m3, a weight per surface area within a range of from 0.4 to 1 kg/m2, and a flow resistance within a range of from 10 to 40 kNs/m4.

Abstract: Apparatus and methods are provided forming a sound attenuating laminate that has a decoupler fiber layer and a mass layer in opposing relationship with each other. The decoupler fiber layer and mass layer of the laminate are heated to the selected temperature in substantially the same amount of time via a hot air source and a heated platen, respectively. The heated laminate is conveyed to a mold and formed into a predetermined three-dimensional configuration via the mold.

Abstract: An acoustical absorber, having the structure: scrim/film/batt/film/scrim. Preferably, the batt is made from about 60% to about 90% by weight natural fiber and about 10% to about 40% synthetic fiber. Also, a method of making the acoustical absorber is provided. Additionally, a method for acoustically insulating a structure with the acoustical absorber is provided. The method for acoustically insulating may include the steps of compressing the acoustical absorber to less than its original volume prior to installing the absorber and releasing the absorber from compression following the installing step, allowing the material to recover and to fill the void of the structure in which the absorber was placed.

Abstract: Vehicle trim components are formed by applying a layer of material onto a mold surface and then selectively applying foam prior to molding operations. Selectively applying foam may include applying foam of different densities in multiple locations and/or applying foam of different thicknesses in multiple locations. The material and foam are subjected to conditions within the mold to produce a trim component having a desired shape. Once de-molded, barrier material may be added and various post-molding operations may be conducted.

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 heat shield includes an inner portion, an outer portion, first and second insulating portions, and a deflecting portion. The inner portion includes a reflective material to reflect thermal energy that radiates from a heat/acoustic source. The outer portion includes a rigid material to provide structural support for the heat shield. The first and second insulating portions are intermediately positioned between the inner and outer portions. The deflecting portion is intermediately positioned between the first and second insulating portions to deflect acoustics from the heat/acoustic source. A method for manufacturing the heat shield is also disclosed.

Abstract: The present invention relates an acoustical insulation material for sound attenuation containing a nonwoven web. Surprisingly, it has been discovered that an acoustical insulation material made from a nonwoven web of thermoplastic fibers having an average fiber diameter of less than about 7 microns, wherein the acoustical insulation has a thickness less than about 3 mm and a density of greater than about 50 kg/m3 is effective as a sound insulation material. The acoustical insulation is very effective as an acoustical insulation material, despite the low thickness and high density of the acoustical insulation. A method of attenuating sound waves passing from a sound source area to a second area using the acoustical insulation material is also disclosed.

Abstract: An air filter for an internal combustion engine includes an air filter housing, the walls of which encompass a filter compartment in which a filter element is positioned, having an intake and an exhaust. Openings that can be sealed off or opened up based upon the operating conditions of the internal combustion engine are provided in a least one wall of the air filter housing. In this way, effective modulation of induction noise (sound modulation) can be achieved in a simple way and manner.