Abstract: A muffler for raising the audible pitch of an internal combustion engine's exhaust note that includes an enclosed case having an inlet and an outlet, and a plurality of flow-directing components which are adapted to subdivide an inlet flow into a plurality of discrete interior flows, including a first interior flow providing the shortest flow length through the muffler between the inlet and the outlet, a second interior flow having a flow length at least about twice the length of the first interior flow, and one or more intermediate flows following by-pass passages to split off from the second interior flow between the inlet and the outlet and having flow lengths between the flow lengths of the first and second flows.

Abstract: A method is disclosed for reducing noise and vibration within a structure of a mobile platform, wherein the noise and vibration are at least in part caused by airflow over an outer skin of the mobile platform parallel to a longitudinal line extending fore to aft along the structure. The method may involve forming the structure such that a fundamental panel vibration mode shape of the structure is not parallel to the longitudinal line.

Abstract: A tensegrity apparatus having multiple tensegrity units for the transmission of solitary waves with adjustable profiles into a material or structure, and the detection of such waves from a material or structure.

Abstract: A pop up device for a curtain, that is compressed to be packaged in a box, and expanded out of said box.

Abstract: An acoustic composite containing at least a first acoustically coupled non-woven composite and a second acoustically coupled non-woven composite, each acoustically coupled non-woven composite containing a non-woven layer and a facing layer. The non-woven layer contains a plurality of binder fibers and a plurality of bulking fibers and has a binder zone and a bulking zone. The facing layer of the second acoustically coupled non-woven composite is adjacent the second surface of the non-woven layer of the first acoustically coupled non-woven composite.

Abstract: In one example, a firearm sound suppressor includes a housing and an interior member. The interior member is disposed within the housing so as to define a chamber between an exterior surface of the interior member and an interior surface of the housing. The interior member includes a lumen and a plurality of vents extending through the interior member between the lumen and the chamber. The vents are adapted to pass combustion gases from the lumen to the chamber. The firearm sound suppressor also includes a blast deflector disposed between the vents and the interior surface of the housing. The blast deflector is adapted to prevent the combustion gases from impinging directly on the interior surface of the housing. Other embodiments are also contemplated.

Abstract: A supporting structure for an anti-noise barrier and relative assembly method are disclosed. The foundation and the structural post of the barrier are a single continuous piece in the shape of a sheet pile. The sheet pile has a first part and a second part of such a length that, in use, the second part is insertable on the ground to realize the foundation, while, contextually, the first part emerges from the ground upwards. The first part of the sheet pile, besides, is provided with connection means through which to be able to connect the sound-absorbent panels, and with a plate on which to lean the panels themselves in such a way that the arrangement on the ground of the foundation and of the structural post is realizable in a single phase to then proceed with the second phase of application of the panels.

Abstract: Methods for vibration and acoustic abatement. The methods comprise providing a substrate with a composite layer deposited thereon, the substrate receiving a vibration energy sufficient to provide at least one bending wave therein, and converting at least a portion of the vibration energy sufficient to cause the at least one bending wave to at least one shear wave in at least a portion of the composite layer. The composite layer comprises an elastomeric polymer matrix comprising carbon nano tubes dispersed or distributed therein. Articles with the composite layer comprising carbon nano tubes disposed thereon are also disclosed and described.

Abstract: An apparatus including an agglomeration of acoustically adsorbing members suitably located substantially on or in a non-conductive support, wherein each acoustically adsorbing member is separated from neighbouring members.

Abstract: This invention is an acoustic device protected by an acoustically transparent low water permeability encapsulant made from an acoustically clear polymer such as polyurethane. High aspect ratio clay nanoparticles are positioned in the substrate in overlapping layers with layers of the substrate interposed. The invention also provides a method for forming an acoustically transparent low permeability encapsulant about an acoustic device. The method includes treating high aspect ration clay nanoparticles to make them organophilic. The treated nanoparticles are then mixed in a polymer resin in such a way as to form an intercalated mixture. A curing agent is added to the mixture, and the mixture is allowed to set. When set the resulting intercalated mixture produces an acoustically clear, low permeability polymer coating.

Abstract: A sound absorbing device of the type adapted to cover the ears of a user and comprising a sound absorbing material, wherein the sound absorbing material comprises of a thixotropic material.

Abstract: A motorsports helmet having an isolation mount defining a receptacle is provided. An adjustment plate is selectively disposed within the receptacle at different depths and includes an ear-cup. The ear-cup is secured relative to the adjustment plate and includes at least two degrees of freedom of movement.

Abstract: A working machine is provided with a revolving upperstructure, working equipment, an engine compartment, a counterweight, a muffler, and an exhaust path for releasing exhaust gas, which has been discharged from the muffler, to an outer side of the revolving upperstructure. The exhaust path includes a tailpipe connected to the muffler and an exhaust pipe for releasing exhaust gas, which has been discharged from the tailpipe, to the outer side of the revolving upperstructure. The counterweight is utilized for the formation of the exhaust path. The exhaust path includes a passage formed in the counterweight and accommodating an upper end portion of the tailpipe inserted therein with a predetermined clearance formed around the upper end portion such that the exhaust gas discharged from the tailpipe can be guided to the exhaust pipe.

Abstract: An acoustic composite containing at least a first acoustically coupled non-woven composite and a second acoustically coupled non-woven composite, each acoustically coupled non-woven composite containing a non-woven layer and a facing layer. The non-woven layer contains a plurality of binder fibers and a plurality of bulking fibers and has a binder zone and a bulking zone. The facing layer of the second acoustically coupled non-woven composite is adjacent the second surface of the non-woven layer of the first acoustically coupled non-woven composite.

Abstract: A moldable acoustic facing comprises cellulosic fibers and synthetic fibers entangled together. The acoustic facing has a basis weight of from about 1.5 to about 5.0 ounces per square yard (osy), a thickness of less than about 0.050?, a mean pore size of between about 8 microns and about 40 microns, and an elongation at break of at least twenty percent. The acoustic facing includes less than about five percent synthetic microfiber and has an acoustic resistance of at least about 250 Rayls.

Abstract: An acoustic dampening panel comprising: (a) a first layer of expanded polypropylene; (b) a solid layer having a surface weight between 2.4 kilograms per meter squared and 25 kilograms per meter squared; and, (c) a second layer of expanded polypropylene, where the first and second layers of expanded polypropylene sandwich the solid layer therebetween. The acoustic dampening panel may further comprise a fourth layer comprising a metal skin, where the solid layer and the metal skin sandwich the second layer therebetween.

Abstract: A compressor assembly having a housing with a number of sound control chambers. A method of controlling a sound level of a compressor assembly having a step of providing a plurality of sound control chambers. A method of controlling a sound level of a compressor assembly having a step of eliminating an operator's line-of-sight view to noise producing components of the compressor assembly. Sound level of a compressor can be controlled by separating the internal volume of a housing which encases at least a portion of a pump assembly to create sound control chambers and/or eliminating an operator's line-of-sight view to noise producing components of the compressor assembly.

Abstract: A muffler for a feed air system of a compressor assembly. The muffler can be a product of a blow molding process and used in a method of sound control for a compressor assembly. A method of controlling sound in a compressor assembly can have the step of providing a feed air and the step of providing the muffler an outlet in communication with an inlet of a pump assembly which can compress the feed air fed through the muffler and into the pump assembly. Sound control for a compressor assembly is also accomplished by adapting a feed air system to have sound control of a feed air path by dampening the sound emitted from a pump system through the feed air path.

Abstract: In one embodiment, the present invention includes an apparatus to reduce downspout noise. The apparatus includes a first and second portion. The first portion has a first diverting angle relative to the water flowing through the downspout. The second portion is coupled to the first portion and has a second diverting angle relative to the water flow. The second angle is greater than the first angle, thereby providing incremental diversion of the water flow. At least a portion of the surfaces may also include a surface detail to provide micro-diversions of the water flow. The diversions of the water may reduce the impact of the water flow and reduce downspout noise.

Abstract: A sound attenuation mechanism made up of multiple substrate layers, including corrugated layers. The use of corrugation provides an inexpensive and manner of forming a plurality of highly effective acoustic attenuation channels throughout the mechanism. The multi-layered mechanism may be provided in a variety of modular forms and sizes which may be combined to form a low-cost, highly effective attenuation housing. For example, such a housing may be utilized to contain otherwise noisy large scale oilfield equipment such as coiled tubing engines. Additionally, where drainage from the housing is sought, a spiraled attenuation channel may be employed such that the effectiveness of the attenuation provided by the housing is not sacrificed.

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: Structured films having acoustical absorbance properties are disclosed. Methods of making and using the structured films are also disclosed.

Abstract: An apparatus for muffling sound can include first and second pivotally connected panels, each of the panels having a front side, a back side opposite the front side, a bottom edge for positioning on a base surface, and a top edge opposite the bottom edge. The panels can be moveable between an open position for use and a closed position for transport, and have complementary sections of sound dampening material, such as a plurality of foam pyramids. The foam pyramids can be positioned on the panels such that they are positioned against each other in an interlocking arrangement when the panels are in the closed position.

Abstract: Air bubbles may be used to reduce radiated underwater noise. Two modalities of sound attenuation by air bubbles were shown to provide a reduction in radiated sound: bubble acoustic resonance damping and acoustic impedance mismatching. The bubbles used for acoustic resonance damping were manifested using gas-filled containers coupled to a support, and the acoustic impedance mismatching bubbles were created using a cloud of freely-rising bubbles, which were both used to surround an underwater sound source.

Abstract: A high-pressure fuel injection pump, including a sound-damping acoustic cover, is mounted on an engine and is part of a direct-inject fuel system for a vehicle. In an exemplary embodiment, the acoustic cover includes a top portion that fits over the fuel injection pump and a side portion that mechanically engages the fuel injection pump, and at least one of the top or side portions is formed from a sound-damping metal laminate material. Sound and/or vibrations that emanate from the fuel injection pump may be transferred to the acoustic cover and converted into thermal energy by the sound-damping metal laminate material.

Abstract: A floor covering having slip-resistance and sound attenuation properties, particularly for reducing levels of sound resulting from high impact interactions. The floor covering includes at least a first layer and a second layer, wherein the first layer includes a particulate material at least partially embedded therein, and the second layer is capable of providing a sound attenuation effect with an acoustic impact sound reduction of at least about 15 decibels.

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: A jet engine adapted for reducing far-field noise levels is disclosed. The jet engine has a plurality of flap assemblies that are disposed around a perimeter of an exhaust port of the jet engine. Each flap assembly is movable between a first position and a second position. The jet engine also includes a plurality of actuators respectively coupled to the plurality of flap assemblies. Each actuator is configured to selectively move the coupled flap assembly between the first and second positions. The jet engine also includes a controller that is coupled to each actuator. The controller is configured to cause at least one actuator to move the coupled flap assembly between the first and second positions at a determined frequency.

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 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 inte

Abstract: An adaptive noise control system is deployed in a box-like structure 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 adaptive noise control system is can be deployed in the dual bulkhead of the vehicle dashboard to provide a constrained volume within which engine noise can be controlled. The adaptive control system generates a mathematical model of the noise to be controlled in response to the acoustic environment identified by sensors placed within the engine compartment. Sensors in the passenger compartment define the effectiveness of the noise control system. The controller is operable to update the mathematical model in response to the changes in the acoustic environment, thus providing the appropriate acoustic response within the dual bulkhead plenum for control of noise along the transfer path.

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: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.

Abstract: A noise control system is directed to the path along which the noise is transmitted from the source of the noise being generated to the receiver of the noise in the passenger compartment of an automotive vehicle. The noise control system is deployed in a box structure, such as the dual bulkhead of the dashboard of the vehicle, to provide a constrained volume within which engine noise can be controlled. The dual bulkhead plenum houses an active noise control apparatus, such as a speaker or a vibrating device, between the bulkheads to be operable with a control algorithm to generate sound that can control the noise or vibrations generated by the engine. The plenum can also be treated with passive noise control materials, such as viscoelastic damping materials, acoustical foam or heavy vinyl barrier and foam to block airborne sound and vibrations, in addition to the active noise control.

Abstract: A system is provided for producing synthetic jets. The system comprises a first synthetic jet ejector equipped with a first diaphragm which operates at a first frequency f1, and a second synthetic jet ejector equipped with a second diaphragm which operates at a second frequency f2. The first and second synthetic jet ejectors are positioned with respect to each other such that the sound intensity of at least one of the first and second synthetic jet ejectors is reduced through destructive interference, wherein f1 and f2 are out-of-phase by ? degrees, and wherein 20???60.

Abstract: A resonator for a dual-flow exhaust system of an engine is provided. The resonator includes a housing defining an enclosure and a baffle spanning the housing and separating a first and second expansion chamber of the enclosure, the baffle including at least one opening. The resonator further includes a first and a second exhaust conduit extending through the baffle and housing, each conduit in fluidic communication with a separate cylinder bank and including a perforated portion fluidly coupled to the enclosure, each perforated portion positioned in separate expansion chambers.

Abstract: A baffle arrangement for a genset enclosure is disclosed. The genset enclosure may include an opening in a side of the enclosure and a plurality of baffles internally supported in the enclosure between the opening and a radiator portion. The baffles may be positioned in a sound path to reflect a sound transmitted along the sound path. A method for reducing sound in a genset enclosure is also disclosed. The method may include arranging a plurality of baffles within the enclosure between an opening and a radiator portion, the baffles being positioned in a sound path to reflect a sound transmitted along the sound path.

Abstract: An aircraft configuration that may reduce the level of roaring jet exhaust noise, infrared radiation, sonic boom, or combination thereof directed towards the ground from an aircraft in flight. The aircraft's nacelles are mounted to the aircraft higher than the wings, with substantially vertical stabilizers outboard of the outermost engine. Noise shifting means are provided such as, for each nacelle, primary chevrons at the core nozzle, secondary chevrons at the fan nozzle, a partial bypass mixer, a long duct full flow mixer, or a combination thereof to provide a shift in spectrum distribution of jet exhaust noise from lower to higher frequency. Variable geometry chevrons may be used with increased immersion to provide such a shift just during noise-restricted portions of an aircraft flight profile. The aircraft aerodynamic structural surfaces serve as noise shielding barriers that more effectively block or redirect the frequency shifted noise up and away from communities.

Abstract: A device for reducing booming noise in a motor vehicle has a wind deflector (3) having openings. The device furthermore has an air source (1), which is arranged in the motor vehicle and connected to the wind deflector. The air provided by the air source can be channeled to the wind deflector and released through the openings (4) thereof.

Abstract: A noise control system 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 smart materials affixed to the walls of the plenum to be operable for selectively changing a property characteristic of the chambers to vary the acoustic resonance of the plenum and change the effectiveness of controlling the transmission of noise energy therethrough. A controller is coupled to the smart materials to change said property characteristic of the smart material in response to noise cancellation requirements.

Abstract: A method and apparatus for mounting a loudspeaker within a cavity in the wall of a room to lessen the transmission of vibration to the wall comprises a weight support member coupled to the speaker cabinet and at least one flexible member extending from the speaker cabinet into engagement with wallboard or other wall sections forming opposite sides of the wall.

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 fluid transfer pipe (1) comprising opposed ends (3, 5) adapted to be connected to respective pipework, the pipe (1) comprising a longitudinal axis (9), the transverse cross section of the pipe (1) varying along the length of the pipe such that the distance radially outwardly from the longitudinal axis (9) to the inner wall of the pipe (1) is non linear along at least part of the length of the pipe. A fluid attenuator comprising such a pipe is also disclosed.

Abstract: A Tier 4 ready silencer that can accept both DOCs and DPFs to meet Tier 3 and can interface with an SCR system to meet Tier 4. The invention includes a silencer compartment with empty filter/catalyst banks in the shape of a V. DOCs and DPFs can be added and arranged in the V-shaped banks as needed. Various exhaust fins direct exhaust flow through the filters/catalysts. Multiple exhaust inlets to the device provide the most direct route possible from the engine outlets. A mixing tube and an SCR system can be added to the output port to comply with Tier 4.

Abstract: An insert for sealing and acoustic damping of a longitudinal cavity having an interior surface, comprising: a) one or more carrier plates made of a polymeric material (A) which does not deform when heated to a temperature not higher than 180° C. and which comprises a main polymer (A1) which gives mechanical strength to the carrier plate, and—at least one vibration-damping polymer (A2), and b) a thermally expandable material (B). The vibration-damping polymer (A2) is preferably selected from the group comprising: thermoplastic polyurethanes, styrene/butadiene block copolymers, hydrogenated styrene/butadiene block copolymers, styrene/isoprene block copolymers, hydrogenated styrene/isoprene block copolymers, styrene/isoprene/styrene tri-block copolymers, and hydrogenated styrene/isoprene/styrene tri-block copolymers.

Abstract: A phonemic crystal is made of a first solid medium having a first density and a substantially periodic array of structures disposed in the first medium, the structures being made of a second solid medium having a second density different from the first density. The first medium has a speed of propagation of longitudinal sound waves and a speed of propagation of transverse sound waves, the speed of propagation of longitudinal sound waves being approximately that of a fluid, and the speed of the propagation of transverse sound waves being smaller than the speed of propagation of longitudinal sound waves.

Abstract: A method for manufacturing a sandwich panel includes, but is not limited to the steps of providing at least one air-permeable core layer and at least one porous cover layer, applying an adhesive onto a first area of the core layer, pressing the cover layer onto the first area of the core layer to connect the cover layer to the core layer, and applying an airstream that from the outside is directed onto the cover layer and that moves through the cover layer and the core layer. By means of such an airstream it is possible to prevent excessive accumulation of adhesive on the cover layer, which otherwise would result in partial blocking of the cover layer. By varying the intensity of the airstream the flow resistance of the arrangement including, but not limited to, the cover layer and the core layer may be determined and set during the bonding process. In this way a sandwich panel with precise sound-absorption behavior can be manufactured.

Abstract: A heating or cooling system comprising a powered fan held in a duct assembly. The powered fan generates acoustic noise when blowing air. The system also comprises an acoustic wave modulator held in the duct assembly. The acoustic wave modulator has one or more fins and is configured to reduce turbulence of the air traveling through the duct assembly.

Abstract: A method for quieting noise and vibration from a crankcase of an engine comprises dispersing a first amount of elemental carbon in a second amount of lubricant oil to yield a concentrated elemental-carbon suspension. The method further comprises adding the concentrated elemental-carbon suspension in an amount effective to quiet the noise and vibration to a third amount of lubricant oil in the crankcase.

Abstract: A system and method for reducing the noise of an airfoil is provided. The airfoil includes a main portion including a leading edge and a trailing edge. The airfoil further comprises a noise attenuator coupled to the main portion and disposed proximate to at least a portion of the trailing edge. The noise attenuator has a chord length in the range of about 0.5 to about 5 times a trailing edge thickness and is fixed relative to the trailing edge. The airfoil can be a rotating blade deployed on a wind turbine. The airfoil can also be deployed on an aircraft as a fixed wing.

Abstract: A sound attenuation canopy for reducing levels of sound passing through an opening comprises a sound absorbing member. The sound absorbing member is comprised of a flexible sound absorbing material and has a first end, a second end and an intermediate portion extending between the first end and the second end. The first end is configured to attach to a periphery of the opening at a first location, the second end is configured to attach to a periphery of the opening at a second location and the intermediate portion is configured to be spaced apart from the opening. When the first end and the second end of the sound absorbing member are attached to the periphery of the opening, at least one side opening is at least partially defined by the intermediate portion and the perimeter of the opening, and a sound transmission flow path through open space between the opening and the side opening comprises at least one change of direction greater than 45 degrees.