Provided is a soundproof structure that is small and light and can sufficiently reduce noise with a high natural frequency of a sound source. There is provided a soundproof structure including a frame having an opening, and at least one membrane-like member fixed to an opening surface where the opening of the frame is formed, in which a rear surface space is formed to be surrounded by the frame and the membrane-like member, and a sound is absorbed due to vibration of the membrane-like member, and a sound absorption coefficient of the vibration of the membrane-like member at a frequency in at least one high-order vibration mode existing at frequencies of 1 kHz or higher is higher than a sound absorption coefficient at a frequency in a fundamental vibration mode.

Provided is a soundproof structure that is small and light and can sufficiently reduce noise with a high natural frequency of a sound source. There is provided a soundproof structure including a frame having an opening, and at least one membrane-like member fixed to an opening surface where the opening of the frame is formed, in which a rear surface space is formed to be surrounded by the frame and the membrane-like member, and a sound is absorbed due to vibration of the membrane-like member, and a sound absorption coefficient of the vibration of the membrane-like member at a frequency in at least one high-order vibration mode existing at frequencies of 1 kHz or higher is higher than a sound absorption coefficient at a frequency in a fundamental vibration mode.

The present disclosure provides a bone conduction speaker, comprising: a vibration assembly, the vibration assembly including a vibration element and a vibration housing, the vibration element being used to convert an electrical signal into a mechanical vibration, the vibration housing being used to contact with a face of a user and to transmit the mechanical vibration to the user in a bone conduction manner to produce a sound; and a resonance assembly including a first elastic element and a mass element, the mass element being connected to the vibration assembly by the first elastic element, wherein the vibration assembly causes the resonance assembly to vibrate, the vibration of the resonance assembly weakening a vibration amplitude of the vibration housing.

A noise attenuating device for reducing acoustic resonance in a cavity of an aircraft with an opening in a skin of the aircraft defining a first surface area and an opening peripheral edge includes a connection mechanism for securing the noise attenuating device in proximity to the opening in the skin of the aircraft and an exterior surface. The exterior surface defines a second surface area that is less than the first surface area of the opening and a device peripheral edge, which has a first section having an edge profile complimentary to at least a portion of the opening peripheral edge and a second section having an indented edge profile in relation to the first section such that when the noise attenuating device is secured within the opening, at least one gap is formed between the device peripheral edge and the opening peripheral edge.

A noise attenuating device for reducing acoustic resonance in a cavity of an aircraft with an opening in a skin of the aircraft defining a first surface area and an opening peripheral edge includes a connection mechanism for securing the noise attenuating device in proximity to the opening in the skin of the aircraft and an exterior surface. The exterior surface defines a second surface area that is less than the first surface area of the opening and a device peripheral edge, which has a first section having an edge profile complimentary to at least a portion of the opening peripheral edge and a second section having an indented edge profile in relation to the first section such that when the noise attenuating device is secured within the opening, at least one gap is formed between the device peripheral edge and the opening peripheral edge.

An apparatus is provided for an aircraft propulsion system. This apparatus includes an acoustic panel and a mount. The acoustic panel includes a perforated face skin, a back skin, a perforated intermediate layer, a first cellular core and a second cellular core. The first cellular core includes a first section and a second section. The first section is between and is connected to the perforated face skin and the perforated intermediate layer. The second section is between and is connected to the perforated face skin and the back skin. The second cellular core is between and is connected to the perforated intermediate layer and the back skin. The mount is attached to the back skin along the second section.

The type of acoustic absorber comprises a micro-perforated plate, a cavity behind the micro-perforated plate, a slender and curved main acoustic propagation passage communicating with the cavity, and a set of acoustic filters arranged along the main acoustic propagation passage. These acoustic filters have different cut-off frequencies and are arranged in the order of the cutoff frequencies from high to low from the open end to the closed end of the main acoustic propagation passage. The acoustic filter comprises a section of the main acoustic propagation passage and at least one cavity communicating with the main acoustic propagation passage. The type of acoustic absorber is characterized by adopting a main acoustic propagation passage to provide different phase delay for a micro-perforated plate to realize that a micro-perforated plate effectively absorbs broadband acoustic waves, and by combing the close arrangement of main acoustic propagation passage to achieve the ultra-thin structure.

A method for manufacturing a cellular core for an acoustic panel is provided. The cellular core includes at least one plurality of acoustic cells and a plurality of de-icing channels that extend longitudinally, each de-icing channel being transversely interposed between two successive cells, and the de-icing channels being adapted to channel a de-icing fluid. A manufacturing step includes producing the acoustic cells and the de-icing channels as a single piece such that the cellular core manufactured during the manufacturing step forms a monolithic part.

A method for manufacturing a cellular core for an acoustic panel is provided. The cellular core includes at least one plurality of acoustic cells and a plurality of de-icing channels that extend longitudinally, each de-icing channel being transversely interposed between two successive cells, and the de-icing channels being adapted to channel a de-icing fluid. A manufacturing step includes producing the acoustic cells and the de-icing channels as a single piece such that the cellular core manufactured during the manufacturing step forms a monolithic part.

An aircraft fairing includes a fairing body having an exterior fairing wall and at least one wheel bin. The at least one wheel bin has a side wall extending from an opening in the exterior fairing wall to an end wall. The side wall and the end wall define a cavity of the at least one wheel bin in fluid communication with the opening in the exterior fairing wall. An acoustic resonator is mounted to an outer surface of the side wall of the at least one wheel bin and is in fluid communication with the cavity. The acoustic resonator has a resonant frequency substantially similar to a cavity modal frequency of the at least one wheel bin at an aircraft flight condition.