30 results about "Interior noise" patented technology

The invention relates to the technical field of automobile interior noise control, in particular to an automobile pressure release valve noise control method based on a local resonance acoustic superstructure. The method comprises the steps of obtaining basic data of a target vehicle; carrying out multi-working-condition noise testing based on the basic data of the target vehicle, and determining a main noise frequency; a main radiation source of pressure release valve noise is positioned based on the main noise frequency, and a key path of noise propagation in a vehicle is analyzed; extracting a noise main peak frequency based on the main noise frequency, the main radiation source and the key path, and determining a core noise reduction frequency band; setting a noise reduction target based on the core noise reduction frequency band; constructing a three-dimensional finite element model of the acoustic superstructure based on the basic form of the superstructure; inputting the acoustic superstructure part into the three-dimensional finite element model for simulation analysis; and a simulation analysis result is compared with an initial test result of the target vehicle, a noise reduction effect is analyzed, and the superstructure part is optimized. The sound absorption and insulation structure for specific frequency noise can be designed according to noise sources at the positions of different vehicle types.

sound insulation insert (10), which is designed in particular for the interior noise reduction of a residential ventilation system that can be installed in a wall opening and has at least one axial fan having a central motor hub, wherein the sound-insulating insert (10) is made essentially of an acoustically absorbing material at least on its surfaces in contact with the airflow, and wherein the sound-insulating insert (10) has an annular outer element (12) for insertion into a wall penetration duct, wherein the sound-insulating insert (10) has an inner element (14) in an area which, in the mounted position, adjoins the motor hub of the at least one axial fan in the residential ventilation system, which is connected to the outer element (12) via at least one web (16a-c), so that an annular gap-shaped passage for the airflow is formed between the outer and inner elements, which passes through the at least one The bridge (16a-c) is divided into sections (18a-c), characterized by the fact that the outer element (12), which includes at least one web (16a-c) and the inner element (14) are made of an acoustically absorbing rigid or soft foam material, in particular a melamine resin foam.

The utility model discloses an atomizer with damping device, including front shell, rear shell and air pump, and the second air inlet of air pump outside is connected through the first air inlet of rear shell bottom with the hose, and the second air outlet is provided with the first air inlet top, and the second air outlet is connected through the first air outlet of rear shell side with the hose, and the outer storehouse is fixed on the rear shell, and the air pump is in the outer storehouse, and the air pump both sides are sleeved with the damping bubble cotton, and the damping bubble cotton and air pump set up in the inner storehouse rear shell inside, and the inner storehouse front shell is compatible with the inner storehouse rear shell, and both are fixed through the inner storehouse screw, and the inner storehouse rear shell bottom is connected through the damping device screw and the damping device, and the damping device bottom is fixed on the rear shell through the fixed nut. The utility model discloses through the setting of damping bubble cotton, outer storehouse and inner storehouse can absorb and block the inside noise and reach the purpose of noise reduction, and the setting of damping device, damping sponge can play the effect of damping, and then improve the experience of user's use.

The application provides a control method and device of a vehicle raindrop knocking sound elimination system and a vehicle, including: obtaining vehicle interior noise information, the vehicle interior noise information including first noise data before it rains and second noise data when it rains, and calculating a volume difference between the vehicle interior noise before it rains and the vehicle interior noise when it rains; comparing the volume difference with a preset first volume threshold, if the volume difference is less than the first volume threshold, then starting or stopping the raindrop knocking sound elimination system; if the volume difference is greater than or equal to the first volume threshold, then stopping the raindrop knocking sound elimination system. The application compares the volume difference with the first volume threshold, thereby determining whether the noise volume generated by the rain is easy to be perceived by the vehicle interior personnel. If it is easy to be perceived, then starting the raindrop knocking sound elimination system; otherwise, then stopping the raindrop knocking sound elimination system, reducing energy consumption and reducing the influence of the raindrop knocking sound elimination system on the vehicle interior personnel.

The invention relates to an idling charging noise optimization method and device of a vehicle, electronic equipment and a medium, and the method comprises the steps: calculating the suspension loading force of the vehicle through measuring a related transfer function, the actual vibration acceleration of an indication point and the actual sound pressure of a target response point under the idling charging working condition of the vehicle by using an inverse matrix method; coupling the whole vehicle model and the acoustic cavity finite element model of the vehicle to obtain a whole vehicle interior noise vibration prediction simulation model; inputting the suspension loading force into the whole vehicle interior noise vibration prediction simulation model, and predicting the vehicle interior vibration noise under the idling charging excitation of the whole vehicle state of the vehicle; and identifying a problem characteristic frequency meeting a preset optimization condition from the in-vehicle vibration noise, and determining an idling charging noise optimization scheme of the vehicle based on the problem characteristic frequency so as to optimize the whole vehicle model by using the noise optimization scheme. Therefore, the technical problems of high time cost and high labor cost due to the fact that the real vehicle needs to be tested for multiple times to determine the optimization scheme according to the test data in the related technology are solved.

The present disclosure relates to a noise suppression device, a noise suppression method and a program that makes it possible to adequately reduce noise. Sensor filters generated from vehicle interior noise and sensor signals, and compensation filters generated from sensor signals, control point noise, and sensor signals, are pre-assigned to each other. At the time of an NC process, without a control point microphone, a compensation filter is used that is assigned to a sensor filter generated from vehicle interior noise and a sensor signal. This can be applied to an NC device.

This invention provides an active noise cancellation method and microphone vibration damping device that suppresses divergence, belonging to the field of automotive active noise cancellation technology. It detects the cabin's sealing status using sensors on the doors, windows, and sunroof. If sealed, noise signals are collected using the error on the microphone vibration damping device and a reference microphone. These signals are then processed by an active noise cancellation filter to generate a secondary noise signal, which is played through a speaker. If open, the engine speed is read from the vehicle's CAN signal to generate a reference noise signal, which is also played. The dashboard displays the cabin sealing status and the active noise cancellation system's operating status, determined based on the noise signal collection and noise cancellation signal playback. This invention automatically switches noise cancellation modes according to the cabin's sealing status, effectively reducing interior noise when sealed and appropriately playing reference noise when open, minimizing the impact on the system filter's robustness. Relevant information is displayed on the dashboard, allowing users to intuitively understand the cabin status and system operation.

An apparatus and method for diagnosing a microphone of a vehicle reduce an interior noise by applying an active road surface noise reduction method, learn sounds collected using a plurality of microphones to generate a simulated signal for a specific microphone, and detect a failure of the specific microphone by comparing the simulated signal with an actually measured sound of the specific microphone so that noise reduction efficiency can be improved by distinguishing a noise from an interior sound, a failed microphone can be accurately detected using the sounds of the plurality of microphones, the spread of an unnecessary noise can be prevented by diagnosing a failure of the specific microphone, and a more comfortable and stable interior environment can be provided to occupants.

The application discloses a kind of real-time evaluation system and method of automobile interior noise based on deep learning model.The system includes audio acquisition module, feature extraction module, deep learning model module and man-machine interaction module;The deep learning model module includes working condition identification submodule and noise evaluation submodule;The working condition identification submodule inputs the pre-trained improved ResNet working condition identification model with the calibrated mel spectrum feature, and outputs the working condition category of current noise;The noise evaluation submodule inputs the pre-trained CRNN noise evaluation model with the calibrated Log mel spectrum feature, and outputs the comprehensive noise quality score;The man-machine interaction module is used to provide intuitive operation and monitoring interface for user.The application can automatically identify the specific test working condition of vehicle, output the comprehensive score highly consistent with the feeling of professional evaluator, while providing intelligent test progress guidance and visual monitoring.

The utility model relates to the technical field of vibration reduction of railway vehicles, in particular to a polyurethane foam pad vibration reducer for railway vehicles, which comprises a plurality of bases which are arranged between vehicle floor interlayers and connected end to end, each base is of a hollow cuboid structure, and the surface of each base is subjected to anodic oxidation treatment. The multi-layer composite vibration reduction unit is composed of a polyurethane foam layer and a high-damping rubber layer nested in the polyurethane foam layer, the molecular structure of the polyurethane foam layer is in a porous cell form, and the internal porous cell form is in internal and external surrounding type gradient distribution, that is, the outer-layer aperture of the polyurethane foam layer is smaller than the inner-layer aperture of the polyurethane foam layer. The polyurethane foam layer and the high-damping rubber layer are compounded, the polyurethane foam layer adopts aperture gradient distribution, the outer-layer small-aperture foam quickly responds to high-frequency vibration, and the inner-layer large-aperture foam absorbs low-frequency energy and covers full-band vibration suppression, so that vibration transmission is attenuated, noise in a vehicle is reduced, and the service life of the vehicle is prolonged. And the comfort of passengers is obviously improved.

The invention provides an angle-adjustable active noise reduction control method and device for an air conditioner and the air conditioner, and relates to the technical field of air conditioner noise reduction. The method comprises the steps that the number of users in all areas in the space where the air conditioner is located is determined; the areas are areas where different sectors with the position of the air conditioner as the circle center intersect with the space where the sectors are located; adjusting the position of an active noise reduction module to enable a noise reduction signal output by the active noise reduction module to cover an area with the most users; an air conditioner internal noise signal is obtained, and the active noise reduction module is controlled to directionally output a noise reduction signal according to the noise signal; the noise reduction signal and the noise signal are equal in amplitude and opposite in phase. The control logic is simple and easy to implement, and can be used in a large range; and active noise reduction processing is conducted on the user concentrated area, so that the volume of the air conditioner noise is reduced, adverse effects of the noise on users are avoided, and the user experience is improved.

The present application relates to the technical field of household appliances, and provides a gas water heater, which comprises a bottom shell, a burner installed on the front face of the bottom shell, a back cover plate installed on the back face of the bottom shell and defining an air inlet channel with the bottom shell, the back cover plate being provided with a first air inlet communicating with the air inlet channel, the bottom shell being provided with a second air inlet at a position away from the first air inlet, the second air inlet communicating with the air inlet of the burner and the air inlet channel, and a front cover plate installed on the front face of the bottom shell and located between the burner and the bottom shell. The gas water heater has the structure that the bottom shell and the back cover plate cooperate with each other, the bottom shell and the back cover plate weaken the internal noise, the sound insulation effect is enhanced, the cavity between the bottom shell and the back cover plate forms a long and wide air inlet channel, the path length of the noise along the air inlet channel to the outside is greatly increased, the transmission loss of the noise to the outside is effectively improved, and the flow channel resistance is greatly reduced.

The present invention discloses a multi-channel active noise reduction system and method for improving in-vehicle sound quality. The system comprises an audio transceiver module, an audio data transmission module, a noise signal analysis and preprocessing module, a reference signal generation module, a FELMS-based multi-channel noise reduction algorithm module, and a basic parameter setting module. The noise signal analysis and preprocessing module performs noise signal analysis and preprocessing on the noise source signal, then sends the reference signal required for control to the noise reduction algorithm module. After performing calculations based on the received error signal, the module generates an anti-noise signal to achieve noise cancellation. The present invention can analyze the sound quality characteristics of in-vehicle noise and conduct targeted control. This improves the in-vehicle sound quality while meeting the requirements of a larger interior noise reduction space, thereby enhancing the driving experience.

The invention belongs to the technical field of aircraft interior noise reduction design, and particularly relates to an exterior aircraft interior noise reduction observation window assembly. The assembly comprises a pressing ring, the cross section of the pressing ring is in an L shape, the pressing ring comprises a first pressing plate and a second pressing plate, and a containing cavity is formed between the first pressing plate and the second pressing plate; the E-shaped soft ring sleeve is installed in the containing cavity, the E-shaped soft ring sleeve and the pressing ring are bonded and fixed through an adhesive, and two grooves are formed in the E-shaped soft ring sleeve; the double-layer transparent part is arranged in the groove of the E-shaped soft ring sleeve; wherein after the pressing ring, the E-shaped soft ring sleeve and the double-layer transparent part are assembled, the pressing ring, the E-shaped soft ring sleeve and the double-layer transparent part are installed at the end of the cylindrical observation window of the aircraft interior trim from the outer side of the aircraft interior trim, and the pressing ring and a wall plate of the cylindrical observation window of the aircraft interior trim are fixed through a fastener. Sound insulation and noise reduction of the aircraft interior observation window can be achieved, and installation is easy and convenient.

The utility model relates to the technical field of air compressors, and provides a shock absorption device of a full oil-free mute vortex air compressor, which comprises a shock absorption component, a hush pipe and a connecting plate, and absorbs and dissipates vibration energy and improves the shock absorption effect through the cooperative work of a pneumatic spring shock absorber and a damping column. The sound insulation cover can effectively isolate internal noise during operation of the air compressor, noise pollution to the surrounding environment can be reduced, noise control is further optimized through the silencing pipe, and noise during air exhausting of the air compressor is reduced. And the bolt fixing holes can ensure tight connection among all components. And the top non-slip mat and the rubber non-slip mat provide an additional non-slip effect, so that the stability and the safety of the air compressor during operation are ensured. The shock absorption device of the air compressor has the advantages of being mute, shock-absorbing, stable in structure, anti-skidding, protecting and the like.

The technical solution employed by the present invention is a method for controlling acceleration roar noise, comprising the following steps: conducting an acceleration noise test on a prototype vehicle and extracting an audio spectrum of the roar noise generated by the main engine order; calculating the contribution of the noise from the left, right, and rear suspension paths to the interior noise based on the audio spectrum of the main engine order, and selecting the path with the largest contribution to the interior noise as the main noise transmission path; optimizing the vehicle body structure under the main transmission path; obtaining a vehicle body interior noise transfer function curve and identifying problematic points in the vehicle body interior noise transfer function; and, based on the problematic points in the vehicle body interior noise transfer function, selecting methods to increase the engine dynamic stiffness or optimize the beam system, panels, or component modes of the vehicle body structure, thereby optimizing the vehicle body noise, vibration, and harshness performance. This invention can address this type of noise phenomenon in the early stages of vehicle model project development, reducing development costs and improving the overall vehicle NVH performance.

The present invention provides a vehicle noise reduction method and system, comprising: collecting road noise information, vehicle window status, vehicle speed, and interior noise; obtaining corresponding delay state values ​​based on the window status and vehicle speed using a time delay estimation method based on offline secondary channel modeling; and performing Newton interpolation estimation on the delay state values ​​to obtain secondary channel compensation; after outputting the secondary channel compensation, calculating feedforward secondary acoustic channel compensation and feedback secondary acoustic channel compensation; calculating the wind noise contribution to the interior noise based on the real-time window status and vehicle speed, and adjusting a first proportional factor based on the wind noise contribution; and calculating a speaker output signal based on the feedforward secondary acoustic channel compensation, the feedback secondary acoustic channel compensation, and the first proportional factor to perform active noise reduction. This solution can effectively improve the interior noise reduction effect of a vehicle.

This application relates to a method, system, device, and readable storage medium for evaluating abnormal noises in vehicle interiors, belonging to the field of vehicle detection technology. It includes sending an excitation signal corresponding to a target excitation mode to the vehicle ECU via a vehicle-mounted application. The ECU then drives a vehicle-mounted horn corresponding to the target excitation mode to generate vibration excitation, thereby exciting vibrations in the interior components. During the vibration of the interior components, an in-vehicle noise signal is acquired using an in-vehicle microphone. The in-vehicle application performs spectral analysis on the in-vehicle noise signal to generate an evaluation result for abnormal noises. This application generates an excitation signal through a vehicle-mounted application to drive a vehicle-mounted horn to generate vibration excitation, thereby exciting vibrations in the interior components. Spectral analysis of the noise signal acquired by the in-vehicle microphone quickly identifies the interior components causing the abnormal noise, achieving an evaluation of interior noises. This method is not only low-cost and highly efficient but also provides objective data support, resulting in higher evaluation accuracy.

The invention belongs to the technical field of aircraft interior noise reduction design, and particularly relates to a built-in aircraft interior noise reduction observation window assembly. According to the assembly, the cross section of an outer pressing ring is in an L shape, and the outer pressing ring comprises a first outer pressing plate and a second outer pressing plate; the cross section of the inner pressing ring is in an L shape, the inner pressing ring comprises a first inner pressing plate and a second inner pressing plate, the first inner pressing plate and the first outer pressing plate are bonded and fixed through an adhesive, and a containing cavity is formed between the second inner pressing plate and the second outer pressing plate; the E-shaped soft ring sleeve is installed in the containing cavity, and two grooves are formed in the E-shaped soft ring sleeve; the double-layer transparent part is arranged in the groove of the E-shaped soft ring sleeve; after the outer pressing ring, the inner pressing ring, the E-shaped soft ring sleeve and the double-layer transparent part are assembled, the outer pressing ring, the inner pressing ring, the E-shaped soft ring sleeve and the double-layer transparent part are installed in the cylindrical observation window of the aircraft interior trim from the inner side of the aircraft interior trim, and the outer pressing ring, the inner pressing ring and a wall plate of the cylindrical observation window of the aircraft interior trim are fixed through fasteners. Sound insulation and noise reduction of the aircraft interior observation window can be achieved.

The application relates to the technical field of vehicles, in particular to a noise identification method and device of a vehicle, a vehicle and a storage medium, wherein the method comprises the following steps: acquiring a vibration acceleration signal and a vehicle interior noise signal when the vehicle drives on a preset impact road and performing time domain preprocessing; constructing a cross spectrum matrix based on the vibration acceleration signal after the time domain preprocessing and performing target principal component analysis to obtain a principal component signal of the cross spectrum matrix; then obtaining a transfer function matrix from each wheel center excitation point to an interior response point by using a hammering method test; calculating and identifying road impact loads at each wheel center of the vehicle based on the principal component signal and the transfer function matrix by using an inverse matrix method; and calculating contribution amount quantization results of each noise transmission path to the vehicle interior noise signal according to the road impact loads and the transfer function matrix. Therefore, the problems of noise identification result distortion and instability caused by the ill-conditioned transfer function matrix and the coupling of multiple reference point signals in the related art are solved.

The invention discloses an EPDM (Ethylene-Propylene-Diene Monomer) sealing sound insulation component for a through type tail lamp, a preparation method of the EPDM sealing sound insulation component and vehicle application, an EPDM sheet is produced through a supercritical closed-cell foaming process, the EPDM sheet has a micro-nano closed-cell structure, the density is 55-750 kg / m, the hardness is 15-70 Shore C, and the compression set rate is not greater than 5%; an environment-aging-resistant pressure-sensitive adhesive layer is attached to one side of the EPDM sheet, and the other side of the EPDM sheet is a sealed contact surface; and the sealing sound insulation component is formed into a shape matched with the combination surface of the penetrating type tail lamp and the vehicle body through die cutting processing. By means of the mode, rain leakage and dust invasion of the long combination face of the penetrating type tail lamp can be effectively prevented, the driving safety in rainy days is remarkably improved, and a long-acting sealing solution is provided for the penetrating type tail lamp; the noise in the vehicle at the speed of 120 km / h is not higher than 57 dB (A), the noise in the vehicle at the speed of 60 km / h is not higher than 53.2 dB (A), the noise is reduced by 3-5 dB (A) compared with that of a mainstream electric vehicle, the library-level mute level is achieved, driving fatigue is reduced, the sound insulation and noise reduction performance is remarkable, and the driving comfort is improved.

Disclosed are an active noise reduction method and device for a vehicle, and a storage medium. The active noise reduction method includes the following steps: generating two reference signals according to a target noise to be denoised; generating a control signal and sending it to a sound reproduction device; filtering the reference signals to obtain filtered reference signals; calculating a noise signal; updating an auxiliary control parameter; calculating an updated auxiliary control parameter-based error signal; and updating the control parameter. The method actively reduces the noise of vehicle engines, reduces interior noise pollution, and has a fast convergence speed.

The embodiment of the present application provides a kind of vehicle interior noise reduction method, equipment and storage medium, the method comprises: the first noise of vehicle interior is collected, the first noise characteristic information of the first noise is determined and the first position information of generating the first noise;According to the first noise characteristic information and the first position information, the first audio characteristic information of the first noise reaching each preset position is determined;According to the first audio characteristic information of each preset position, the directional audio playing equipment at each first position is controlled respectively to generate the second audio opposite the phase of corresponding first noise, to eliminate the first noise at each preset position. It is intended to reduce the noise in the vehicle interior without increasing sound insulation material and damping device, improve the ride experience effect.

The invention provides a method and device for measuring contribution of noise of an air inlet pipe opening to noise in a vehicle, and the method comprises the steps: arranging a noise generator in an air filter of a test vehicle, and arranging a plurality of sound pressure sensors in the test vehicle according to a noise measurement point arrangement strategy; controlling the test vehicle and the noise generator according to a first preset test strategy of the test vehicle, and acquiring first sound pressure information of the test vehicle through the sound pressure sensor; preprocessing the first sound pressure information to obtain the main order of the noise of the vehicle air inlet pipe orifice, and generating a target test strategy according to the main order; controlling the test vehicle and the noise generator according to the target test strategy, and obtaining second sound pressure information of the test vehicle through the sound pressure sensor; the second sound pressure information is analyzed and calculated, and the contribution of the noise of the vehicle air inlet pipe opening to the noise in the vehicle is generated. Therefore, the air inlet noise contribution can be accurately quantified, and a reliable data basis is provided for optimizing the NVH performance of the air inlet system and setting the target line of the air inlet noise.

The invention provides a method and device for determining the contribution degree of noise in a cabin, electronic equipment and a vehicle, and relates to the technical field of intelligent cabins, and the method comprises the method and device for determining the contribution degree of the noise in the cabin, the electronic equipment and the vehicle. Determining the contribution degree of each plate to the cabin noise according to the pre-stored dynamic stiffness and the pre-stored decoupling sound pressure sensitivity; wherein the decoupling sound pressure sensitivity of each plate is independent sound pressure sensitivity excluding the sound pressure influence of other plates. The decoupling sound pressure sensitivity in the application is an independent sound pressure response obtained after interference of other plates is effectively eliminated through decoupling calculation. Therefore, the specific contribution of each plate to the noise in the vehicle under different operation conditions can be accurately quantified, so that valuable quantitative data is provided for NVH optimization of the vehicle.

Occupant presence detection system (10) for a vehicle (100), in particular for a passenger car with - at least one outside sound sensor (20) for detecting outside sounds (SA) outside a vehicle interior (12), wherein the outside sounds (SA) form an outside sound profile (SAR), - a processor unit (30) configured to process the outside noise profile (SAR) detected by the at least one outside room audio sensor (20) using a signal processing algorithm (31) by defining a model-based interference noise profile (SAN) using a vehicle-based characteristic noise transmission model based on the outside noise profile (SAR) recorded outside the vehicle (100), which is designed to be out of phase with the outside noises (SAP) transmitted into the vehicle interior (12) and perceptible in the vehicle interior (12), - at least one loudspeaker (28) through which the out-of-phase interference noise profile (SAN) can be output in the vehicle interior (12), and - at least one interior audio sensor (25) for detecting interior noise (SP) within the vehicle interior (12), wherein the interior noise (SP) recorded by the at least one interior audio sensor (25) is classified by means of a classification algorithm (35) such that signs of life originating from occupants (50) are recognizable, wherein the classification algorithm (35) is configured to recognize characteristic noises or noise patterns of humans or animals.

The utility model provides a balance shaft noise detection device, and belongs to the technical field of mechanical tests. The balance shaft noise detection device comprises a test assembly and a fixed assembly, the fixed assembly is divided into a wind breaking part and a movable part, the test assembly is arranged in the fixed assembly, and the test assembly is divided into two test paths of an exterior line and an interior line to synchronously test noise of a balance shaft in a front cover and noise in a carriage. The fixing assembly is used for installing and fixing the device outside the vehicle during motion testing. According to the utility model, noise monitoring analysis can be simultaneously carried out near an engine balance shaft in a front cover and in a carriage, the front cover and a vehicle door are sealed under extrusion protection of vehicle exterior lines and vehicle interior lines, internal noise dissipation and external interference are prevented, external protection can be carried out on a test instrument, and the test efficiency is improved. And the device can be conveniently protected and fixed in an outdoor test state.

This utility model discloses an interior panel and a rail vehicle, applied to rail vehicle vibration absorption technology. The interior panel includes an interior panel body, a plurality of vibration absorbers disposed on the surface of the interior panel body, and a limiting component. The vibration absorbers are spaced apart, and each vibration absorber includes an elastic layer component and a mass layer component. The elastic layer component is located between the interior panel body and the mass layer component. The limiting component covers the side of the mass layer component opposite to the interior panel body and is fixed to the surface of the interior panel body. The interior panel provided by this utility model can improve the low-frequency sound insulation of the rail vehicle body, reduce interior noise, and improve comfort. Due to the structure of the interior panel body, it is easy to operate, saves space, and allows for flexible arrangement.

The invention discloses a whole vehicle interior noise reproduction system and a whole vehicle interior noise reproduction method. The whole vehicle interior noise reproduction system is characterized in that the whole vehicle interior noise reproduction system comprises a plurality of vehicle exterior loudspeakers, one or more vehicle interior loudspeakers, a microphone array and a controller, the vehicle exterior loudspeakers, the vehicle interior loudspeakers and the microphone array are connected with the controller, the vehicle exterior loudspeakers are arranged in a semi-anechoic chamber and surround the outer circle of a vehicle, and the microphone array is arranged in the semi-anechoic chamber and surrounds the outer circle of the vehicle. The plurality of external loudspeakers are divided into a plurality of layers with different heights, and one or more external loudspeakers are arranged on each layer; the in-vehicle loudspeaker is arranged in the vehicle; the microphone array is arranged in front of a seat of the vehicle. According to the invention, by arranging the loudspeaker outside the vehicle and the loudspeaker inside the vehicle, the noise inside the vehicle is well reproduced, subjective and objective evaluation is carried out on different acoustic schemes in a laboratory environment, and the final product is ensured to meet an expected comfort index. And meanwhile, the loudspeakers outside the vehicle are arranged in a layered manner at different heights, so that the non-uniformity of a space sound field is avoided.

The invention relates to the technical field of road milling, and discloses a road milling machine which comprises a rack body, a console is fixedly mounted at the top of the rack body, a transmission structure is arranged in the rack body, a conveying structure is arranged in the rack body, and a sound insulation mechanism is arranged at the bottom of the rack body. According to the road milling machine, by arranging the sound insulation mechanism, when the ground needs to be milled and repaired, the machine frame body is driven to the road surface through the control console, then the milling structure and the electric hydraulic telescopic rod are started, the ground is milled, and a large amount of noise is generated; according to the sound insulation mechanism, a part of noise is reduced through the metal sound absorption layer, the noise is spread outwards to the outer sound insulation box, the other part of noise is reduced through the mineral wool sound absorption layer, and therefore double sound absorption and noise reduction are achieved, the noise can be greatly reduced through the double sound absorption plates, and the hearing of workers is prevented from being affected.