An acoustic core may include an array of resonant cells configured as a plurality of resonant cell groups. The resonant cell groups may include a plurality of resonant cells configured as a partitioned resonant cell that include a converging resonant cell and a diverging resonant cell. The converging resonant cell and the diverging resonant cell may be defined by a plurality of cell walls integrally formed with one another and a partition integrally formed with the plurality of cell walls. The partition may at least partially delimit the converging resonant cell from the diverging resonant cell. The converging resonant cell may define an upper resonant space delimited by the partition and a top face of the array of resonant cells. The diverging resonant cell may define a lower resonant space delimited by the partition and a bottom face of the array of resonant cells.

An acoustic core may include an array of resonant cells configured as a plurality of resonant cell groups. The resonant cell groups may include a plurality of resonant cells configured as a partitioned resonant cell that include a converging resonant cell and a diverging resonant cell. The converging resonant cell and the diverging resonant cell may be defined by a plurality of cell walls integrally formed with one another and a partition integrally formed with the plurality of cell walls. The partition may at least partially delimit the converging resonant cell from the diverging resonant cell. The converging resonant cell may define an upper resonant space delimited by the partition and a top face of the array of resonant cells. The diverging resonant cell may define a lower resonant space delimited by the partition and a bottom face of the array of resonant cells.

A sound absorption structure includes resonators that constitute separate bodies from each other and that produce Helmholtz resonance and a pliable coupling member that couples the plurality of resonators. Each of the resonators has a tubular shape or a pipe shape, includes an opening portion provided on a first end face, and includes a bottom portion provided on a second end face that is an opposite end face to the first end face. Each of the resonators is pliable.

A sound absorption structure includes resonators that constitute separate bodies from each other and that produce Helmholtz resonance and a pliable coupling member that couples the plurality of resonators. Each of the resonators has a tubular shape or a pipe shape, includes an opening portion provided on a first end face, and includes a bottom portion provided on a second end face that is an opposite end face to the first end face. Each of the resonators is pliable.

A sound reducer (10) has a housing (14) with a housing wall bounding an interior space (141). The housing wall has a mantle (142) extending longitudinally along a housing axis. Two end walls (143) are transverse to the housing axis. A main tube (12) extends through the interior space (141) and has a first and second ends (121). Windows (22) are formed as tube wall openings within the interior space (141). The first end (121) of the main tube (12) is fixed at a first passage (18a) through the housing wall, and the second end (122) of the main tube (12) is fixed at a second passage (18b) through the housing wall. At least the second passage (18b) passes eccentrically through one of the end walls (143). The main tube (12) is curved in a main plane and the first passage (18a) passes through the mantle (142).

A cushioning element for use in a vehicle, for example in an aircraft, includes at least one tuned absorber embedded within the cushioning element. The tuned absorber is tuned to absorb noise at a predetermined frequency of at least 20 Hz. A method of providing noise absorption within a cabin of a vehicle includes determining a predetermined frequency of at least 20 Hz of an undesirable noise within the cabin, and configuring an internal structure of a cushioning element to define a tuned absorber tuned to absorb noise at the predetermined frequency, the cushioning element in use being located in the cabin.

A cushioning element for use in a vehicle, for example in an aircraft, includes at least one tuned absorber embedded within the cushioning element. The tuned absorber is tuned to absorb noise at a predetermined frequency of at least 20 Hz. A method of providing noise absorption within a cabin of a vehicle includes determining a predetermined frequency of at least 20 Hz of an undesirable noise within the cabin, and configuring an internal structure of a cushioning element to define a tuned absorber tuned to absorb noise at the predetermined frequency, the cushioning element in use being located in the cabin.

An acoustic absorption structure includes: at least one acoustic element which has at least one cavity delimited by at least one enclosure comprising at least one first drainage orifice passing through the enclosure, and a rotational indexing system making it possible to position the acoustic element so that at least one first drainage orifice is positioned in proximity to or at a lowest point of the cavity. An aircraft propulsion assembly including such an acoustic absorption structure is also described.

An acoustic absorption structure includes: at least one acoustic element which has at least one cavity delimited by at least one enclosure comprising at least one first drainage orifice passing through the enclosure, and a rotational indexing system making it possible to position the acoustic element so that at least one first drainage orifice is positioned in proximity to or at a lowest point of the cavity. An aircraft propulsion assembly including such an acoustic absorption structure is also described.

A method of using an acoustic resonator including receiving at a first stage of a resonator an incoming acoustic wave. The method further includes resonating the incoming wave with a flexible membrane, a taper of the flexible membrane, and a cavity of a first stage, thereby producing synergistic effect on a resulting acoustic resonance. Additionally, the method includes transforming an acoustic energy associated with the incoming acoustic wave into an elastic energy, wherein the elastic energy is channeled through the flexible membrane, thereby reducing an intensity of the incoming acoustic wave and resulting in a first reduced incoming acoustic wave. Further the method includes transferring the first reduced incoming acoustic wave through a hole of a neck of the flexible membrane. The method also includes transferring a first pressure wave caused by a perturbation in the flexible membrane into a second stage, thereby producing a second acoustic wave.