Abstract: A blower with a silencer has the blower including an axial fan including a casing, a motor attached to the casing, and a rotor having a shaft portion attached to the motor and rotated and a blade formed to protrude to an outer side of the shaft portion in a radial direction, and a silencer attached to the casing, in which the silencer includes a resonator that selectively silences a dominant sound generated by the axial fan, the silencer is disposed at a position in which at least a part of the silencer overlaps with the shaft portion, as viewed from a rotation axis direction of the rotor, and in a case in which, in a cross section perpendicular to a rotation axis of the rotor, a circle around the rotation axis, which has a radius of a line connecting the rotation axis and a point of a most distal end of the blade, is defined as a rotation region, an area of the silencer in the cross section perpendicular to the rotation axis is smaller than an area of the rotation region.

Abstract: To effectively reduce a low-frequency noise resulting from vibration of a peripheral wall of a ventilation path. The present invention provides a ventilation path with a soundproof structure including a ventilation path that includes an open end and a soundproof structure against a sound emitted from the ventilation path.

Abstract: An acoustic system includes a duct that has a function of causing a fluid to flow therein and has a tubular shape, an internal sound source that is disposed inside the duct on an upstream side or at an outer peripheral portion of the duct, which communicates with an inside of the duct on the upstream side, or an external sound source that is on an outside from an end portion of the duct, and a membrane-shaped member that is formed as a part of a wall of the duct and vibrates in response to sound. A structure including the membrane-shaped member and a rear surface closed space thereof causes acoustic resonance to occur, transmits the acoustic resonance from the sound source into the duct, and suppresses sound radiated from the other end portion of the duct on a downstream side. The external sound source is at a distance within a wavelength at a frequency of the acoustic resonance on the outside from the end portion of the duct.

Abstract: To provide an air passage type silencer and an acoustic impedance change structure of which the absorbance is high, that suppresses generation of a wind noise, and that has a high sound attenuation effect in a low-frequency band. Provided is an acoustic impedance change structure through which a sound propagates, the acoustic impedance change structure including at least in this order: a first impedance matching region that is connected to an inlet portion and in which an acoustic impedance gradually decreases; an acoustic impedance constancy region; and an outlet portion, in which Zcham<Zin and Zcham<Zout are satisfied, where Zin is an acoustic impedance in the inlet portion, Zcham is an acoustic impedance in the acoustic impedance constancy region, and Zout is an acoustic impedance in the outlet portion, and a first terminal structure acoustically connected to the acoustic impedance constancy region is provided.

Abstract: To provide a silencing structure and a silencing system having a high sound absorbance in a low frequency region. A silencing structure that is installed in a tubular member, the silencing structure includes a cavity portion, an opening portion through which the cavity portion communicates with the tubular member, and a closing portion that closes the cavity portion at a position facing the opening portion, in which a cross-sectional area of the cavity portion on a side of the opening portion is larger than a cross-sectional area of the cavity portion on a side of the closing portion.

Abstract: An object is to provide a silencing system that can achieve both high ventilation performance and high soundproof performance, can silence a plurality of pieces of resonant sound, and has high general-purpose properties since the silencing system does not need to be designed according to a tubular member. The silencing system includes one or more silencers that are disposed in a tubular member provided to penetrate a wall separating two spaces, and satisfies “0<Re[Bn]<1” and “Im[Bn]>0” in a case where a standardized effective modulus of elasticity in an interior space of the tubular member in which the silencers are disposed is denoted by Bn.

Abstract: An object is to provide a silencing system that includes a silencer disposed in a ventilation sleeve, can suppress the generation of negative pressure in the interior, and can prevent a door or the like of an interior entrance from being difficult to open. The silencing system includes one or more silencers that are disposed in a ventilation sleeve provided to penetrate a wall separating two spaces, and “?A>10C?(0.1/P)×TL” is satisfied in a case where a gap equivalent area of the ventilation sleeve in which the silencer is installed is denoted by ?A and a normalized sound transmission loss in an octave band in which a first resonant frequency of the ventilation sleeve is present is denoted by TL. C denotes a constant determined by a measurement system in a case where there is no silencer and P denotes a transmission efficiency coefficient.

Abstract: A fan, and a silencer that silences a sound generated by the fan are provided, in which the silencer has a resonance characteristic, the silencer is disposed at a position connected to a sound field space of the sound generated by the fan, and a sum of an absorbance and a reflectivity of the silencer at a resonance frequency is 10% to 43% and a standardized half-width of the silencer is more than 0.05 and 0.25 or less.

Abstract: Provided is a soundproof structure that is small and light and can reduce a noise with a high specific frequency of a sound source at a plurality of frequencies at the same time.

Abstract: Provided is a soundproof structure that is small and light and can reduce a noise with a high specific frequency of a sound source at a plurality of frequencies at the same time.

Abstract: Provided is a soundproof structure that is small and light and can reduce noise with a high natural frequency of a sound source at a plurality of frequencies at the same time. The soundproof structure according to the embodiment of the present invention includes a plurality of membrane-like members that are overlapped to be spaced from each other, a support that is made of a rigid body and supports each of the plurality of membrane-like members so as to perform membrane vibration, an inter-membrane space that is sandwiched between two adjacent membrane-like members among the plurality of membrane-like members, and a rear surface space that is formed between one membrane-like member at one end of the support in the support among the plurality of membrane-like members and the one end of the support, in which each of the plurality of membrane-like members absorbs a sound by performing the membrane vibration in a state where the one end of the support is closed.

Abstract: A soundproof structure body includes a first tube structure and a second tube structure connected to the first tube structure and having a cross-sectional area different from the first tube structure, in which a structure body having a cross-sectional area smaller than a cross-sectional area of the first tube structure is installed in the first tube structure, and a transmission loss in a case where the structure body is installed in the first tube structure with respect to a case where the structure body is not installed in the first tube structure is positive at two frequencies adjacent to each other and difficult to generate an air column resonance mode in the first tube structure. This soundproof structure body generates a soundproof effect even at frequencies other than air column resonance of a tube structure such as a duct or a muffler, has a small size, and can obtain a high transmission loss in a wide-band.

Abstract: Provided is a box-shaped soundproof structure that is small and light and can sufficiently reduce noise with a natural frequency of a sound source. A box at least a part of which is opened; and a sound reduction structure including a resonator disposed in the box are included, and a sound generated from a sound source disposed in contact with an outer surface of a wall of the box or in the box and emitted from an open surface of the box to the outside is reduced by the sound reduction structure.

Abstract: Provided is a soundproof structure body including an opening member that forms an opening tube line having a cross-sectional area S, and at least two resonance structures for sound waves that are installed inside the opening tube line, and in a case where a cross-sectional area of the resonance structure is defined as Si, a width thereof is defined as di, an interval between the two resonance structures is defined as L, an impedance of the two resonance structures is defined as Zi, and a synthetic acoustic impedance is defined as Zc, a condition of Expression (1) is satisfied at a resonance frequency f0 at which a theoretical absorption value At is a maximum value. This soundproof structure body can realize high absorption using a plurality of resonance structures. At(f0, L, S, Si, di, Zi)>0.

Abstract: A soundproof system includes a tube structure having one or more opening ends and a soundproof structure having an opening portion or a radiation surface. The following Expression (1) is satisfied in a case in which a phase difference between sound incident on the soundproof structure and sound re-radiated from the soundproof structure is defined a phase difference as ?1; for one or more maximum values of the pressure of sound formed in the tube structure, a distance between the opening portion or the radiation surface and a position where the sound pressure has a maximum value in the tube structure is L; a wavelength of the incident sound is ?; and a phase difference ?2 is defined as 2?×2L/?: |?1??2|??/2??(1). The soundproof system with a small size can obtain high transmission loss in a wide band.

Abstract: 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.

Abstract: A first ventilation duct line has a first portion having a first sectional area, a second portion having a second sectional area larger than the first sectional area, and a third portion having an inclined inner face connecting the first portion and the second portion to each other. Further, there is a second ventilation duct line having an opening portion positioned on an inner side of the first portion of the first ventilation duct line.

Abstract: Provided is a silencing tubular structure body that has high strength and can be disposed in a narrow space. A tubular member including a tubular portion having a tubular shape, and a frame portion having at least a part formed integrally with an inner peripheral surface side of the tubular portion; and a lid member that is exchangeably disposed on an opening surface of the frame portion of the tubular member are included, in which the frame portion and the lid member form a resonant silencing structure.

Abstract: An axial fan that includes a casing having an inner space that penetrates in one direction, and a rotor blade disposed in the inner space of the casing, and a silencer that is disposed at a position connected to the inner space of the axial fan are provided, in which the axial fan has a sound pressure distribution having a position at which a sound pressure is high and a position at which the sound pressure is low in a circumferential direction in the inner space during driving, and the silencer is disposed at the position of the axial fan in the circumferential direction at which the sound pressure is high and is not disposed at the position at which the sound pressure is low.

Abstract: A fan, and a silencer that silences a sound generated by the fan are provided, in which the silencer has a resonance characteristic, the silencer is disposed at a position connected to a sound field space of the sound generated by the fan, and a sum of an absorbance and a reflectivity of the silencer at a resonance frequency is 10% to 43% and a standardized half-width of the silencer is more than 0.05 and 0.25 or less.