Abstract: A sound attenuation device for reducing noise generated by a leaf blower includes a shell, which is insulated and defines an interior space. A first cutout that is positioned in a front of the shell and a second cutout that extends from the front into a first side of the shell are shaped substantially complementarily to an engine compartment of a leaf blower and to a cross-sectional profile of a pipe of the leaf blower, respectively. The first cutout is configured to insert the engine compartment into the interior space so that the pipe extends from the shell through the second cutout. A coupler that is coupled to the shell proximate to the front is configured to couple the shell to the leaf blower so that the shell substantially encapsulates the engine compartment. The shell is configured to attenuate sound that is generated by an engine of the leaf blower.

Abstract: An acoustically and thermally effective capsule for an electric motor of a motor vehicle, particularly of an electric vehicle, includes several acoustically and thermally effective capsule elements that can be connected to one another, and at least one fastening member for fastening the capsule to a housing of the electric motor.

Abstract: A vehicle soundproofing structure includes: a soundproofing mechanism configured to suppress sound from leaking outside from a vehicle by absorbing, dissipating, or cancelling sound inside a vehicle cabin, and a controller configured to enable operation of the soundproofing mechanism when the vehicle is stationary, and to disable operation of the soundproofing mechanism when the vehicle is travelling.

Abstract: An automotive vehicle soundproofing part having a body that includes a plurality of interlaced and/or bonded fibers. The body includes, in its thickness: a porous upper region of granular elements dispersed between the fibers; and a porous lower region with no dispersed granular elements, or formed of a concentration of dispersed granular elements lower than the concentration in dispersed granular elements of the porous upper region. The porous upper region has an air passage resistance at least 100 N·m?3·s greater than the air passage resistance of the porous lower region.

Abstract: Systems and devices of the various embodiments may provide a low-drag, variable-depth acoustic liner having shared inlet volumes. Various embodiments may include a low-drag, variable-depth acoustic liner providing aircraft noise reduction. Acoustic liners according to the various embodiments may be used in engine nacelles and/or on external surfaces of an aircraft to reduce acoustic radiation. Acoustic liners according to various embodiments may provide increased broadband acoustic performance with less drag than conventional liners. Various embodiments may provide an acoustic liner with a reduced open area of the facesheet, and therefore reduced drag of the liner, when compared with conventional acoustic liners.

Abstract: A ventilation assembly and methods of forming the same includes a ventilation grille having reducing acoustic bodies configured to attenuate sound of the ventilation assembly. Arrangement of the acoustic bodies can form phononic crystal to attenuate sound and can be tuned to desired sound bands to reduce sounds.

Abstract: Systems and methods are presented for dampening noise in a rotating machine having a rotatable shaft defining an axis of rotation. An acoustic panel assembly may comprise an annular casing, a hook, and an acoustic panel carried by the hook. The acoustic panel comprises a radially inner skin, a radially outer skin, and an acoustic treatment member having a plurality of walls extending between the radially inner skin and the radially outer skin thereby defining a plurality of radially oriented cells. A portion of the cells adjacent a first axial edge of the acoustic panel are filled with a reinforcement material and shaped to form a lip having sufficient strength to support a portion of the acoustic panel. The panel is positioned so that the lip is axially and radially retained by the hook.

Abstract: A production method for an acoustic panel comprising a step of producing a composite structure, a step of providing inserts, wherein each insert comprises a nozzle formed as a hollow cylinder with a through-bore and a cap comprising a base formed as a cylinder and a cover formed as a cone, and wherein the base is accommodated in the bore, a step of positioning the inserts in the composite structure by penetration of the cover into the composite structure so that the bore opens at one side and the other of the composite structure, a step of polymerizing during which the composite structure with the inserts is polymerized, a step of removing the caps, a first step of fixing a honeycomb structure to the polymerized composite structure, and a second step of fixing a rear skin to the honeycomb structure.

Abstract: An assembly forming an acoustic insulator having a first sheet, a pierced second sheet, and a plurality of first and second structures. Each first structure comprises a first and a second strip, wherein each is shaped to form half of the wall of a cage and wherein, for two successive halves, each strip comprises a facet of a joining wall. Each second structure is made up of a first and a second strip, wherein each is shaped to form half of the wall of a cone, wherein. For each strip, at least one of the wall halves of each cone is pierced. For two successive halves, each strip comprises one facet of the connecting wall. Each cone is located in a cell and each connecting wall is located between the two facets of a joining wall, and, between two adjacent first structures, a second structure is likewise fitted.

Abstract: One-way sound transmission devices include a planar, acoustically reflective substrate having an aperture that is traversed by an elastic membrane. On one face of the substrate, two resonators are symmetrically spaced apart from the membrane at a first distance, configured to enable constructive interference between the resonators and the membrane. On the opposite face of the substrate, two other resonators are symmetrically spaced apart from the membrane at a second, greater, distance, configured to enable destructive interference between the resonators and the membrane.

Abstract: A vehicle wheel includes: a pair of vertical walls that are provided upright on an outer circumferential surface of a well portion and extend in a circumferential direction; and a sub air chamber member that is provided between the pair of vertical walls to be held by frictional force generated between the sub air chamber member and the pair of vertical walls and includes an extending wall portion.

Abstract: An acoustic shield for protecting a vibrational sensitive device includes a first unit cell and a second unit cell. The first unit cell includes a first locally resonant unit. The first locally resonant unit controls a first phase gradient and the first unit cell includes a first surface. The second unit cell includes a second surface proximate to the first surface. The second unit cell includes a second locally resonant unit embedded along the second interface. The second locally resonant unit controls a second phase gradient. The first phase gradient is different from the second phase gradient. The first unit cell and the second unit cell comprise a super cell. The acoustic shield is configured such that a vibrational wave from a first side of the super cell to a second side of the super cell is substantially attenuated.

Abstract: There is provided a soundproof structure capable of obtaining a sufficient soundproofing effect by suppressing the leaking of sound due to a diffraction phenomenon in a partition member used for soundproofing. A soundproof unit, which has a frame body having an opening portion and a film that is disposed so as to cover the opening portion and vibrates according to a sound incident on the film, and a partition member, to which one or more soundproof units are attached, are provided.

Abstract: A broadband ultrathin acoustic wave diffusion structure has a plurality of acoustic wave diffusion units. Each acoustic wave diffusion unit has at least one acoustic wave propagation section, and an acoustic wave focused section communicating with the acoustic wave propagation section is arranged according to needs. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused cavity is a variable-section cavity. The acoustic wave propagation section is formed by a simply connected acoustic wave propagation passage with a close end. Different acoustic wave diffusion units have different lengths of the simply connected acoustic wave propagation passages. The maximum length of the simply connected acoustic wave propagation passage may be dozens or even hundreds of times of the thickness of the acoustic wave diffusion structure, which can meet the diffusion requirements for low frequency acoustic waves to the maximum extent.

Abstract: An assembly is provided for an aircraft propulsion system. This assembly includes a first acoustic panel and a second acoustic panel. The first acoustic panel includes a first perforated skin, a first non-perforated skin and a first cellular core arranged between and connected to the first perforated skin and the first non-perforated skin. The first perforated skin is configured with a plurality of first perforations. A first of the first perforations has a first width. A second acoustic panel includes a second perforated skin, a second non-perforated skin and a second cellular core arranged between and connected to the second perforated skin and the second non-perforated skin. The second perforated skin is configured with a plurality of second perforations. A first of the second perforations has a second width that is smaller than the first width.

Abstract: A broadband sparse acoustic absorber includes a periodic array of spaced apart unit cells, generally having a lateral fill factor less than 0.5. Each unit cell includes a pair of joined, and inverted, Helmholtz resonators, having longitudinal and lateral neck portions that are perpendicular to one another. The longitudinal neck portions are typically covered and/or filled with acoustic absorbing material. Sound suppression systems include sound emitting devices that are at least partially surround by one or more such arrays.

Abstract: Systems and methods are presented for acoustic dampening in a rotating machine. The rotating machine has a rotatable shaft defining an axis of rotation and a gas flowpath. A system comprises an acoustic panel affixed to an annular casing. The acoustic panel comprises an acoustic treatment member extending between a radially inner skin and radially outer skin. The radially inner skin extends the full axial and circumferential dimensions of the acoustic panel, and the acoustic treatment member overlays the entirety of the radially inner skin. The acoustic panel is positioned so that the radially outer skin abuts the casing, the abutting surfaces being configured to effect relative axial movement between the surfaces while maintaining contact between the surfaces. The acoustic panel is affixed in position to the casing by one or more fasteners passing through the casing and a portion of the radially outer skin.

Abstract: A seismic source includes a base plate having a bottom surface contacting a surface of the ground. The coupler is connectable to the bottom surface of the base plate and projects downward from the base plate. The coupler contain soil under the base plate during operation. Another seismic source includes a base plate and at least one contact member. The base plate has an upper surface engaging the seismic source, a lower surface configured to contact a soil surface. The contact member projects from the lower surface and has a planar bottom surface with a surface area less than a surface area of the base plate lower surface.

Abstract: An acoustical/vibrational noise reduction system may include a plurality of divider walls spaced from each other, generally parallel to each other, and generally parallel to a direction of transmission of acoustical and vibrational noise from a source of acoustical and vibrational energy and an information handling resource. The acoustical/vibrational noise reduction system may also include a plurality of baffle fins mechanically coupled to the plurality of divider walls, generally perpendicular to the plurality of divider walls, and substantially non-parallel to the direction of transmission of acoustical and vibrational noise from the source of acoustical and vibrational energy and the information handling resource.

Abstract: An acoustic liner that may be for a turbofan engine may comprise a first sidewall, a second sidewall, wherein the first sidewall and the second sidewall define a plurality of cells disposed therebetween, and a pre-cut septum ribbon comprising a plurality of permeable septum coupled together via a plurality of connecting members, with each one of the plurality of permeable septum being generally in a respective one of the plurality of cells.