274 results about "Helmholtz resonator" patented technology

An incubator can include a body, a bed supported by the body, and a canopy defining an interior chamber that includes the bed. The incubator can include any combination of various features configured to reduce sound energy inside the incubator. The incubator can include a passive radiator, a Helmholtz resonator, a meta material absorber, an active noise cancelation system, a vented door latch assembly, an acoustically permeable seal, a pressure relief valve, a lift mechanism that uses a belt drive, double paned canopy walls, a bin with insulating compliant elements, a manual pressure release valve, a pressure differential notification system, non-parallel or curved canopy walls, a mattress with reticulated foam, and / or an acoustic filter.

The technology described herein is directed towards one or more modular metasurfaces arranged with unit cells for sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. The metasurfaces can be arranged in a modular frame structure of surrounding unit cells, positioned behind the server's fan(s), with an opening in the frame structure to facilitate airflow therethrough, without obstructing or substantially obstructing the airflow to the surrounding environment.

The technology described herein is directed towards modular metasurfaces arranged with unit cells for narrowband, wideband and / or multiband sound absorption, in which the unit cells are based on Helmholtz resonators that are deployed in a server rack, proximate to a server, without substantially obstructing airflow from the server fan(s). Each sound absorbing unit-cells is designed and constructed based on a specific resonance frequency, and includes a neck portion and air chamber dimensioned to resonate at the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Differently-dimensioned unit cells can be built into a single metasurface module, thereby facilitating wideband and / or multiband sound absorption with that metasurface. The modular metasurfaces can be attached to the sidewalls of a server rack, or positioned in otherwise empty slots above and below a server, optionally coupled to blanking panels for covering the openings of those slots.

The invention discloses a bionic TENG sensor unit for an artificial throat and a preparation method thereof, and relates to the field of artificial throats, and the sensor unit comprises a gradient micro-dome friction layer, a strain amplification layer, an electrode layer and a back cavity substrate layer. The gradient micro-dome array realizes gradual contact through gradient change of height and diameter; the strain amplification layer converts vertical vibration into horizontal strain by using a cantilever beam-sliding block structure; the back cavity array selectively amplifies vibration at a specific frequency based on the Helmholtz resonance principle. The invention further provides a corresponding preparation method. The preparation method comprises the steps of back cavity forming, electrode deposition, microstructure manufacturing, surface treatment and the like. The sensor has the advantages of high sensitivity, good frequency selectivity and strong durability, and is particularly suitable for detecting weak laryngeal vibration signals of laryngeal patients.

The technology described herein is directed towards a metasurface arranged with unit cells for broadband and / or multiband sound absorption, in which the unit cells are based on the principles of Helmholtz resonators. Deeply subwavelength sound absorbing unit cells are designed and constructed based on desired resonance frequencies. Each unit cell includes a neck portion and air chamber dimensioned to resonate at a desired resonance frequency and thereby inverse phase cancel corresponding frequencies of incoming sound waves. Differently designed and arranged subgroups of unit cells are part of the metasurface, which can be positioned proximate to a noise source. As practical examples, the metasurface or multiple metasurfaces can be placed near or wrapped around a computer server or rack of servers to absorb fan noise. The metasurface components (including the unit cells) can be printed by a 3D printer to result in a thin, light-weight, and cost effective noise absorbing metasurface.

The invention relates to the technical field of noise control, and discloses a combined noise reduction and sound absorption unit and a sound absorption board, sound absorption unit structures are periodically arranged and combined to form the sound absorption board with a large area, the sound absorption board is installed on an indoor wall or ceiling of a gas power plant, and indoor low-frequency broadband sound absorption and noise reduction are achieved. The sound absorption device comprises a first sound absorption assembly, the first sound absorption assembly comprises a first shell and a first micro-perforated plate arranged on the first shell, and the first micro-perforated plate is arranged on the first shell; the second sound absorption assembly comprises a second shell, a second micro-perforated plate arranged above the second shell and a second Helmholtz resonant cavity arranged below the first shell; the third sound absorption assembly comprises a third shell, a third micro-perforated plate arranged above the second shell and a plurality of third Helmholtz resonant cavities arranged below the first shell; the first sound absorption assembly, the second sound absorption assembly and the third sound absorption assembly are distributed in parallel.

------ Acoustic Enclosure and Method for Leveling an Acoustic Enclosure The present invention relates to an acoustic enclosure (20) comprising a loudspeaker (21) mounted flush on a front face of the enclosure (20), characterized in that at least one Helmholtz resonator (26) is formed on the front face of the enclosure (20) between each lateral edge of the front face and the loudspeaker (21), the at least one Helmholtz resonator (26) being dimensioned to have a band gap to block the propagation, in the plane of the front face of the enclosure (20), of acoustic waves in the useful frequency band of the loudspeaker (21). Figure to be published with the abstract: Figure 6a

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies selected via interchangeable portions. A sound absorbing unit cell is designed and constructed in two parts based on a desired resonance frequency, such as a neck portion and air chamber portion. The portions are dimensioned such that when coupled together, Helmholtz resonators are formed that resonate at a desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A portion with different dimensions can be interchanged to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention relates to the technical field of sound absorption, noise reduction and impact resistance, in particular to a multifunctional tunable bionic sound absorption and collision prevention integrated superstructure and a preparation method thereof.The multifunctional tunable bionic sound absorption and collision prevention integrated superstructure comprises a shell, an upper sound absorption layer, a lower sound absorption layer and a middle collision prevention layer, the sound absorption layer is provided with a plurality of curved-surface microwell plates which are connected end to end to form a cavity, and the embedded pipe is combined with the cavity to form a Helmholtz resonator; the anti-collision layer is composed of an energy absorption unit array. The preparation method comprises the steps that a three-dimensional model is firstly built, then a laser scanning mode and parameter printing are set, then heat treatment is conducted, then cutting and layer taking are conducted, and finally the superstructure is manufactured through glue joint. The sound absorption and noise reduction functions and the energy absorption and anti-collision functions are integrated, the sound absorption performance is improved through the bionic structure, energy is efficiently absorbed through the middle layer dot matrix, adjustable performance and lightweight design are achieved through parameterized design, the additive manufacturing process is simple, convenient and efficient, and large-scale production and application are facilitated.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via MEMS actuators. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A bimorph MEMS actuator and / or moveable part in the resonators, controlled by a controller, facilitates changing of the airflow the unit cells to adjust the resonant frequencies thereof, to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via a shared tuning element, e.g., a screw, or a piezoelectric actuator. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Collectively moveable floors in the resonators facilitate changing the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via actuators, e.g., piezoelectric motors. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. Moveable partitions in the resonators, controlled by piezoelectric actuators, facilitates changing of the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention discloses a low-frequency sound absorption device for a wind tunnel corner flow deflector, and the device comprises a housing which is internally provided with a low-frequency sound absorber and an impedance matching layer. The low-frequency sound absorber comprises a Helmholtz resonance cavity, a sealing ring and an elastic support, the Helmholtz resonance cavity is distributed in the sealing ring in a square lattice or rectangular lattice mode, and the sealing ring is connected with the shell through the elastic support; the impedance matching layer comprises a porous material layer, an air matching layer and a gradual change section cavity, the porous material layer is connected with the surface, closest to sound wave incidence, of the shell, the air matching layer is located between the porous material layer and the gradual change section cavity, and the sectional area of the gradual change section cavity is gradually increased in the sound wave incidence direction. The thickness of the low-frequency sound absorption device does not exceed 650 mm, the low-frequency sound absorption device is high in aerodynamic noise absorption coefficient at the low frequency band of 50-200 Hz, has excellent high-temperature resistance, can stably operate in the working environment of 150 DEG C or above, and meets the strict working conditions of a wind tunnel laboratory.

The technology described herein is directed towards a metasurface arranged with unit cells for narrowband sound absorption, in which the unit cells are based on Helmholtz resonators that can have their resonant frequencies adjusted via MEMS actuators. A sound absorbing unit-cell is designed and constructed based on a general resonance frequency, and includes a neck portion and air chamber dimensioned to resonate close to the desired resonance frequency and thereby inverse phase cancel corresponding narrowband frequencies of incoming sound waves. A moveable partition in the resonators, controlled by MEMS actuators, facilitates changing of the resonators' air cavity dimensions, to adjust the resonant frequencies to cancel acoustic waves of different frequencies corresponding to noise, which can change over time. The unit cells can be distributed as part of a metasurface, which can be positioned proximate to a noise source to phase cancel the noise.

The invention discloses a tunable MEMS (Micro Electro Mechanical System) structure based on a piezoelectric laminated structure, which comprises a substrate, the substrate is provided with a front surface and a back surface, the back surface of the substrate is provided with a back cavity, the back cavity provides a vibration space for a vibrating diaphragm, and a piezoelectric layer grows on the front surface of the substrate. A height plate is arranged on the front side of the substrate in a sealed mode, a dielectric cavity is formed by the internal space of the height plate and the substrate, the piezoelectric layer is located in the dielectric cavity, a through hole communicated with the dielectric cavity is formed in the side wall of the height plate, and a Helmholtz resonant cavity of the vibrating diaphragm is constructed by the dielectric cavity. According to the tunable MEMS structure based on the piezoelectric laminated structure, the height plate can form a Helmholtz resonant cavity of the vibrating diaphragm, the resonant frequency of the vibrating diaphragm is adjusted, and energy is efficiently coupled.

The invention discloses a low-frequency broadband sound absorption metamaterial adaptive wing and a design method thereof, and belongs to the technical field of aircraft design. The problem that in the prior art, a traditional aircraft wing and a design method thereof are difficult to achieve the low-frequency and broadband noise reduction effect is solved. The wing comprises a leading edge inner side slat, a leading edge outer side slat, a main wing, a trailing edge inner side flap and a trailing edge outer side flap, the leading edge inner side slat and the leading edge outer side slat are connected with the front side of the main wing, and the trailing edge inner side flap and the trailing edge outer side flap are connected with the rear side of the main wing; the metamaterial sound absorption strips are embedded into concave cavities of the leading edge inner side slat and the leading edge outer side slat respectively, the metamaterial sound absorption strips are embedded into the leading edge of the main wing, each metamaterial sound absorption strip is composed of a Helmholtz resonator array composed of single-layer Helmholtz resonator units, and each metamaterial sound absorption strip is provided with a micro-perforated surface with continuous curvature. The noise reduction level of the wing is effectively improved, the sound absorption frequency band is wider, and the method can be applied to sound absorption wing design.

The invention relates to the technical field of acoustic metamaterial structures, in particular to a high-bearing coupling stepped Helmholtz cavity honeycomb sound absorption structure which comprises a plurality of honeycomb structures arranged periodically. A top micro-perforated hole is formed in the center of the top surface of the honeycomb structure, a vertical sound channel is formed in the center of the interior of the honeycomb structure, and a plurality of Helmholtz resonant cavities are formed in the periphery of the interior of the honeycomb structure; the vertical sound channel is communicated with the micro-perforated structure, and the heights of the Helmholtz resonant cavities are distributed according to an arithmetic progression; and the vertical sound channel is communicated with the Helmholtz resonant cavity through a resonant cavity micro-perforated hole. Through collaborative innovation of acoustic topological optimization and mechanical bearing design, the technical paradox that low frequency needs a thick layer and light weight is difficult to bear load of a traditional sound absorption material is broken through, and an innovative solution is provided for cabin acoustic design of aerospace, high-speed rails and other high-end equipment.

The invention discloses a neck embedded ring type Helmholtz resonator, which relates to the technical field of low-frequency sound absorption structures and comprises a resonator main body, an embedded neck and a porous material lining. The resonator main body comprises an outer wall surface and a closed cavity; the embedded neck part penetrates through the top wall surface of the main body and comprises a neck part wall surface and an internal periodic convex ring structure; the porous material lining is attached to the inner wall of the closed cavity, and a first gap is formed between the porous material lining and the wall face of the neck. According to the resonator, the sound energy dissipation capacity and parameter harmonility are improved through the neck circular ring, the low-frequency sound absorption capacity is enhanced through the porous material in the cavity, the sound absorption peak value and frequency can be regulated and controlled by adjusting the parameters of the neck and the circular ring and selecting the type of the porous material, and the resonator is simple in structure, wide in application and beneficial to production.

The invention relates to the technical field of sound absorption and noise reduction, in particular to an anti-impact sound absorption and noise reduction lattice superstructure which comprises an array formed by connecting a plurality of sound absorption cavities, each sound absorption cavity is a truncated octahedron formed by a plurality of panels, and the panels comprise eight regular hexagonal panels and six quadrilateral panels. The two adjacent edges of every two adjacent panels are connected through a hollow truss, and a micro hole is formed in the center of each panel. According to the adjustable Helmholtz resonator, the hollow structure is introduced, stress concentration at truss nodes is effectively reduced, the panels are arranged between the adjacent trusses, an internal air phase is constructed through the micropore design, the sound absorption frequency band of the structure is widened, the sound impedance of the structure can be adjusted through the micropores, and therefore the multiple complete adjustable Helmholtz resonators are formed; when the frequency of incident sound waves is close to the inherent frequency of the resonator, the air columns in the micropores generate strong vibration, sound energy is consumed due to the thermal viscosity effect, and the sound absorption and noise reduction structure can have good sound absorption and energy absorption effects while having good mechanical performance.

The invention relates to the field of building materials, in particular to a novel light sound insulation composite wallboard and a preparation method thereof.The composite wallboard comprises a first layer and a second layer which are compounded in sequence; the first layer is a gradient closed-cell foam layer, and the density of the first layer is distributed in a gradient increasing mode from the first surface away from the second layer to the second surface compounded with the second layer. The second layer is an integrated micro-perforated-adjustable neck depth honeycomb layer and comprises a micro-perforated panel, an adjustable neck depth element and a honeycomb core which are arranged in sequence; the micro-perforated panel is connected with the first layer, the neck depth adjustable element is an elastic film, and the elastic film, the micro-perforated panel and the honeycomb core jointly define a plurality of Helmholtz resonant cavities. According to the light sound insulation composite wallboard, efficient introduction of sound waves is achieved through impedance gradual change design, the adjustable resonance dissipation unit conducts targeted absorption on low-frequency noise, full-frequency-band and high-performance air sound isolation from low frequency to high frequency is achieved, and dual optimization of acoustic performance and space efficiency is achieved.

The invention discloses a strong premixing combustion chamber for restraining combustion noise based on a Helmholtz resonant cavity, and relates to the technical field of energy and power. Air and fuel enter the mixing cavity through corresponding connectors to be strongly premixed, premixed gas enters the hearth to be combusted through slit channels among water cooling channel branch pipes, a water cooling channel array can prevent backfire, the Helmholtz resonant cavity is connected with the hearth through a cavity neck and is provided with an air film cooling channel, the size of the Helmholtz resonant cavity needs to measure combustion noise, and a frequency spectrum is analyzed to obtain characteristic frequency. The neck length, the cross section area and the resonant cavity volume are calculated according to a Helmholtz resonance formula, and the sound absorption effect is verified in combination with a low-order thermoacoustic model. Combustion efficiency is improved through the strong premixing and slit water cooling design, tempering is prevented, NOx is reduced, the diffusion combustion problem is solved, the targeted design resonant cavity is matched with air film cooling, the defects that an existing silencing structure is large in size, poor in adaptation and low in high-temperature reliability are overcome, complex active control is not needed, cost is low, applicability is high, and the application range is wide. And cooperative control of high efficiency, low emission and unstable combustion is realized.

The invention discloses an active regulation and control type piezoelectric acoustic coding metasurface and a use method thereof in the acoustic field, the acoustic coding metasurface comprises a plurality of active regulation and control type piezoelectric acoustic coding units, and each active regulation and control type piezoelectric acoustic coding unit comprises a shell, a piezoelectric composite sheet and an external circuit; the two ends of the shell are open, and piezoelectric compacts are embedded in the shell. The piezoelectric compacts divide the interior of the shell into two symmetrical Helmholtz resonators. The piezoelectric composite sheet is connected with an external circuit of the shell; the external circuit switches open and short circuit states, so that the transmission phase difference of sound waves with working frequency is pi after passing through the active regulation and control type piezoelectric acoustic coding unit, and the sound waves are respectively used as a coding type 0 and a coding type 1. According to the invention, the problems of insufficient reconfigurable capability and slow switching response speed of the existing acoustic coding metasurface are solved.

The invention relates to the technical field of acoustic metamaterial, in particular to an acoustic metamaterial integrating vibration reduction, sound insulation and sound absorption and a preparation method of the acoustic metamaterial. The acoustic metamaterial capable of giving consideration to vibration reduction, sound insulation and sound absorption comprises a sound absorption functional layer, a sound insulation functional layer and a vibration reduction functional layer, the sound absorption function layer adopts a series-parallel Helmholtz resonant cavity coupling porous material and is used for realizing a broadband sound absorption effect; the sound insulation functional layer adopts a polyurethane filling gradient gradual change minimal curved surface and is used for realizing a broadband sound insulation effect; the vibration reduction function layer is coupled based on a band gap mechanism and used for achieving the broadband vibration reduction effect. The function of comprehensively controlling the environmental noise by means of vibration reduction, sound insulation and sound absorption can be achieved, the efficient control capability on the environmental noise is achieved, the design and manufacturing complexity is low, and the device can be conveniently used in various noise occasions.

The invention belongs to the technical field of sound absorption and noise reduction devices. In particular, the present disclosure provides acoustic structures and related methods that may be used to buffer or attenuate medium-high frequency acoustic waves. The sound absorption and noise reduction composite structure comprises a back plate; a honeycomb core; the honeycomb core is filled with the porous sound absorption material in four sections with equal thickness according to the density gradient change; the perforated top plate is bonded with the honeycomb core through an adhesive film; corresponding to the round holes in the perforated top plate, the porous material in the honeycomb core needs to be perforated. The problems that a traditional perforated plate-honeycomb sandwich structure is narrow in sound absorption frequency band and poor in middle-high frequency band sound absorption effect are solved, and meanwhile the defects that a porous material with low strength is insufficient in mechanical support and prone to loss in use are overcome. According to the sound absorption and noise reduction composite structure, the porous sound absorption material is filled in the honeycomb core in a gradient manner, and the through hole structure is introduced, so that the sound absorption performance of the composite structure in middle and high frequency bands is greatly improved, and the sound absorption and noise reduction frequency band width of the whole composite structure is widened. The device is simple in structure and has the characteristic of light weight.

The wave energy capturing and wave absorbing integrated device based on the Helmholtz resonance principle comprises a dike body, the dike body is sequentially provided with a front baffle, a front air chamber, a middle air chamber, a rear air chamber and a rear baffle in the wave incidence direction, and a three-stage series type wave absorbing structure is jointly formed; a front gas-guide tube and a rear gas-guide tube are respectively arranged at the tops of the front gas chamber and the rear gas chamber, and the front gas-guide tube, a top gas cavity of the middle gas chamber and the rear gas-guide tube are respectively connected with a confluence header pipe through pipelines; a one-way air inlet valve and a one-way exhaust valve are arranged on the top of each air chamber and each air guide pipeline; the air outlet end of the confluence header pipe is connected with a one-way air turbine. On the premise that the physical size of the structure and the construction cost are not remarkably increased, the wave absorbing frequency band can be effectively widened, particularly the wave absorbing performance on long-period waves is remarkably improved, and therefore the defects of a traditional breakwater and a traditional OWC device in the aspects are overcome.

The invention relates to the technical field of silencers, and discloses an impedance combined silencer which comprises a shell with an inner cavity, an air outlet is formed in the side wall of the shell, an air inlet is formed in the bottom of the shell, a sheet type resistive silencing section, a reactive sound absorption resonant cavity and an expansion section which are communicated are sequentially arranged in the inner cavity, the sheet type resistive silencing section is communicated with the air outlet, and the reactive sound absorption resonant cavity is communicated with the expansion section. The expansion section communicates with the air inlet; the first cavity wall and the second cavity wall of the resistant sound absorption resonant cavity are provided with a plurality of holes communicating with the inner cavity and the resistant sound absorption resonant cavity, the first cavity wall and the second cavity wall are oppositely arranged, and the air outlet faces the first cavity wall and the second cavity wall. According to the reactive sound absorption resonant cavity, the cavity wall holes are used for guiding sound waves to be coupled into the reactive sound absorption resonant cavity, Helmholtz resonance is formed, low-frequency noise is effectively absorbed, medium-high frequency noise is further absorbed with the assistance of the sheet type resistive noise elimination section, then the noise elimination frequency band is effectively widened, and low-frequency and medium-high frequency cooperative noise elimination is achieved.

The invention discloses a bent channel-Helmholtz composite low-frequency broadband sound absorber and a design method thereof. The sound absorber is formed by connecting a plurality of bent channel metamaterial sound absorption units around a Helmholtz resonator unit in parallel in a coupling mode. By controlling the impedance of the Helmholtz neck and the impedance of the bending channel, each unit is in an under-loss state, and then the overall critical coupling is realized by utilizing the area coupling effect, so that the sound absorber has the sound absorption coefficient of more than or equal to 0.5 in the frequency band of 267-382Hz under the thickness of 35mm. According to the sound absorber, broadband efficient sound absorption is achieved through impedance coupling of the Helmholtz resonators and the bent channels, the problems that a traditional structure is narrow in frequency band, difficult to regulate and control and the like are solved, and theoretical and technical supports are provided for low-frequency noise control.

Disclosed in the present invention are a sound production unit, a sound production device, and an application apparatus. The sound production unit comprises a vibration system, a magnetic circuit system and a composite shell. The vibration system comprises a diaphragm and a voice coil connected to the diaphragm; the magnetic circuit system is located on one side of the vibration system; a magnetic gap is formed in the magnetic circuit system, the voice coil is suspended in the magnetic gap, and the diaphragm, the voice coil and the magnetic circuit system define a mounting cavity; the composite shell is accommodated in the mounting cavity; a sound absorption cavity and a Helmholtz resonant cavity are formed in the composite shell; a through hole is formed in the side of the Helmholtz resonant cavity facing the diaphragm; the sound absorption cavity is filled with sound absorption particles; a sound absorption hole is formed in the side of the sound absorption cavity facing the diaphragm; and an isolation mesh for isolating the sound absorption particles is arranged at the sound absorption hole. In the present invention, by means of the combined action of the sound absorption cavity and the Helmholtz resonant cavity, high-frequency resonance is improved, the resonance frequency is reduced and the low-frequency resonance peak value of a frequency response curve is reduced, so that the acoustic performance is improved, and a miniaturization design is facilitated; and there is no need to inject a magnetic liquid, thereby ensuring that the acoustic performance of the sound production device is not affected.

The utility model relates to the technical field of loudspeakers, in particular to a loudspeaker device, a vehicle sound box system and a vehicle. The loudspeaker device comprises a shell, a loudspeaker mechanism and an acoustic resistance mechanism, the shell is provided with an open hole and a sound outlet, the loudspeaker mechanism is arranged in the shell and forms a cavity together with the shell, the open hole and the sound outlet are communicated with the cavity, the acoustic resistance mechanism is arranged in the open hole, sound waves emitted by the loudspeaker mechanism are radiated outwards from the sound outlet through the cavity, and the acoustic resistance mechanism is arranged in the open hole. The opening communicated with the cavity is formed in the shell, and the acoustic resistance mechanism is arranged at the opening, so that Helmholtz resonance of the cavity can be destroyed, the acoustic structure of the cavity can be changed, the peak and valley of frequency response are inhibited, the frequency response curve is flatter, and the tone quality is improved. The vehicle sound box system has better sound quality by applying the loudspeaker device. The vehicle has better tone quality by applying the loudspeaker device or the vehicle sound box system.

The present invention discloses a muffler, which comprises: a waveguide provided with a sound wave inlet; a first resonance cavity and a second resonance cavity arranged along the tube length direction of the waveguide, the first resonance cavity being arranged closer to the sound wave inlet of the waveguide than the second resonance cavity, and the first resonance cavity and the second resonance cavity being Helmholtz resonance cavities; a first neck tube communicating with the waveguide is provided on the first resonance cavity, a second neck tube communicating with the waveguide is provided on the second resonance cavity, and the cross-sectional area of the second neck tube is larger than that of the first neck tube. By arranging two Helmholtz resonance cavities with different cross-sectional areas of the neck tubes on the waveguide, the present invention has a relatively high prediction accuracy of the noise reduction effect. Secondly, the first neck tube and the second neck tube adopt a bent tube design, which can not only ensure a more compact structure, but also is beneficial to low-frequency noise reduction and miniaturization design.