Multi-tone-area high-fidelity vehicle-mounted sound amplification system

Abstract

The invention relates to a multi-tone-area high-fidelity vehicle-mounted sound amplification system, which constructs a compartment acoustic fingerprint through an ultrasonic transmitter group, a microphone array and a pressure / environment sensor, solves equivalent point coordinates (x, y, z) and a sound absorption coefficient alpha in real time, and drives a compensation matrix to dynamically optimize the frequency response of a loudspeaker in combination with a passenger coefficient Occup and a temperature and humidity offset delta E. Performing ultrasonic scanning based on Gold code spread spectrum, and completing three-dimensional modeling within 1.8 seconds; a 4 * 3 compensation matrix is originally created to solve load / material / temperature and humidity disturbance, and the full-working-condition frequency response fluctuation is smaller than or equal to + / -1.5 dB; the full-duty low-frequency attenuation is improved by 300%, the sound image drift is smaller than or equal to + / -3 degrees, the voice definition MOS value reaches 4.1, and intergenerational crossing of the vehicle-mounted audio self-adaptive technology is represented.

Description

Technical Field

[0001] This invention relates to the field of vehicle audio system technology, to a multi-zone high-fidelity vehicle sound reinforcement system, and specifically to a multi-zone high-fidelity vehicle sound reinforcement adaptive system and method. Background Technology

[0002] In-vehicle audio systems have long faced technical bottlenecks due to dynamic disturbances in the acoustic environment, mainly manifested in three core issues: In terms of spatial instability, changes in occupants (e.g., from 1 to 5 people) cause low-frequency attenuation exceeding 5dB, the movement of objects causes the sound field to shift backward by more than 0.3m, and changes in temperature and humidity (-10℃ to 40℃) cause sound speed drift exceeding 3%; In terms of material dependence, leather seats have a 40% higher mid-frequency absorption rate than velour, resulting in a 30% decrease in the clarity of human voices, and opening the sunroof further weakens high-frequency reflections by 8dB, producing a harsh listening experience; The real-time defects are particularly prominent, with traditional acoustic modeling taking more than 3 seconds to respond to sudden changes such as door closures, and the model failure rate exceeding 60% under vibration interference.

[0003] Existing solutions have fundamental limitations: preset sound effect modes only support 3-5 fixed scenarios and cannot adapt to continuous changes; multi-microphone noise reduction technology only processes noise below 500Hz and fails for mid-to-high frequencies; and camera-based visual assistance solutions suffer from privacy violations and failure at night. The industry urgently needs to develop an adaptive system that can perceive the acoustic fingerprint of the vehicle cabin in real time and dynamically adjust to overcome these problems. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a multi-zone high-fidelity vehicle-mounted sound reinforcement system, comprising a loudspeaker and including:

[0005] Ultrasonic transmitter array: located at the four corners of the carriage ceiling, configured to transmit linear sweep signals from 20kHz to 40kHz;

[0006] Microphone array: Distributed in the A-pillar, B-pillar, C-pillar and the middle of the roof of the vehicle to capture reflected sound waves inside the vehicle;

[0007] Pressure and environmental sensors: These are installed inside the seats to detect the distribution of occupants and the temperature and humidity of the vehicle interior.

[0008] Signal processing module: Constructs a three-dimensional acoustic model of the carriage by using the time difference of sound wave flight and calculates the sound absorption coefficient α. Generates dynamic equalization parameters based on the occup factor Occup and the temperature and humidity offset ΔE.

[0009] Audio output module: Applying dynamic equalization parameters to drive at least 8 full-range speakers in a distributed layout, with the front sound field speakers embedded in the dashboard and front doors, and the rear sound field speakers embedded in the rear doors and rear shelf;

[0010] The occupancy factor Occup is defined as the ratio of the total pressure sensor weight to 150kg, with an upper limit of 1. The temperature and humidity offset ΔE is calculated using the formula: ΔE=(T-25) / 10+(RH-50) / 20, where T is the current temperature and RH is the current humidity.

[0011] Ultrasonic transmitter assembly:

[0012] It employs Gold code spread spectrum modulation technology with a chip length of 127 bits;

[0013] The launch sequence starts 500ms after the doors are closed, and is triggered sequentially in the order of front left → front right → rear left → rear right of the roof, with an interval of 50±5ms between each adjacent launch.

[0014] The sweep frequency signal satisfies the time-frequency function relationship: the frequency increases linearly from 20kHz to 40kHz, with a duration of 100ms.

[0015] The discretization rule for the occup coefficient is as follows:

[0016] When the total pressure sensor load is less than 20 kg, Occup = 0, indicating an unloaded state.

[0017] When 20kg ≤ total < 150kg, Occup = 0.5, indicating a partial load condition;

[0018] When the total weight is ≥150kg, Occup = 1, indicating a fully loaded state.

[0019] The dynamic equilibrium parameters are generated through a compensation matrix:

[0020]

[0021] Among them, α is the sound absorption coefficient of the material, K is the normalization coefficient with a range of 0.8-1.2, and ΔE is the temperature and humidity compensation factor, the value of which is calculated from the deviation of environmental parameters from the reference conditions of 25℃ and 50%RH.

[0022] The 4×3 compensation matrix is ​​used to solve the frequency response distortion problem under different materials / loads / temperature and humidity conditions, the normalization coefficient K is used to prevent over-compensation from causing sound field distortion, and the ΔE temperature and humidity compensation is used to offset the effect of air density changes on sound speed.

[0023] Also includes:

[0024] The vibration interference suppression unit includes:

[0025] a) A three-axis accelerometer installed below the center console to monitor vehicle vibration intensity in real time;

[0026] b) Vibration response module: when the vertical acceleration > 0.3g and lasts for 0.1 seconds, modeling is stopped and the cached model is called;

[0027] c) Smoothing control module: when vibration lasts for more than 5 seconds, the equalizer Q value is reduced from 10 to 3 to reduce parameter sensitivity.

[0028] The sound absorption coefficient α of a material is determined by a combination of two parameters:

[0029] First, measure the reverberation time RT60 in the 200Hz-5kHz frequency band;

[0030] When RT60 ≥ 0.4 seconds and the attenuation slope of 500Hz-2kHz < -2.5dB / octave, it is determined to be a fleece material with α = 0.25;

[0031] When RT60 < 0.4 seconds and the decay slope ≥ -2.5dB / octave, it is determined to be leather material α = 0.12.

[0032] The attenuation slope is calculated using the rate of change of sound pressure level of the swept signal in the 500Hz-2kHz frequency band:

[0033]

[0034] Acoustic model self-verification mechanism execution: After each scan, the Euclidean distance D between the current model and the reference template is calculated;

[0035]

[0036] If D > 0.35, a rescan is triggered to ensure model validity;

[0037] If D > 0.35 twice consecutively, switch to the default mode and generate fault code 0xE2 to guide the rapid location of sensor faults.

[0038] An adaptive method for vehicle acoustic environment based on the system includes the following steps:

[0039] (1) Environment Triggering Phase

[0040] When a door closing signal is detected, ultrasonic scanning is initiated after a 500ms delay;

[0041] (2) Acoustic modeling stage

[0042] a) The ultrasonic transmitter group transmits 20-40kHz sweep frequency signals in the order of front left → front right → rear left → rear right.

[0043] b) The microphone array collects the reflected waves and calculates the time difference of sound wave flight Δt;

[0044] c) Construct an equivalent three-dimensional acoustic model:

[0045] Define transmitter coordinates:

[0046] T1=(x1,y1,z1), T2=(x2,y2,z2),

[0047] T3=(x3,y3,z3), T4=(x4,y4,z4);

[0048] Establish a system of distance difference equations:

[0049]

[0050] The equivalent point coordinates (x, y, z) are solved using the least squares method, where Δt12 = t1 - t2, Δt13 = t1 - t3, Δt14 = t1 - t4, c is the temperature and humidity compensated sound velocity, c = 340 × (1 + 0.006 × (T - 25)) × (1 + 0.0012 × (RH - 50)), and t1, t2, t3, and t4 are the flight times of the four ultrasonic waves from the transmitters T1, T2, T3, and T4 to the microphone array.

[0051] d) Calculate the sound absorption coefficient α:

[0052] When RT60 ≥ 0.4 seconds and the attenuation slope of 500Hz-2kHz < -2.5dB / octave, it is determined to be a fleece material with α = 0.25;

[0053] When RT60 < 0.4 seconds and the decay slope ≥ -2.5dB / octave, it is determined to be leather material α = 0.12;

[0054] (3) Dynamic compensation stage

[0055] Input parameters α, Occup, ΔE to the compensation matrix:

[0056]

[0057] Adjusting speaker frequency response: The front sound field focuses on sound image localization, while the rear sound field focuses on reverberation compensation;

[0058] (4) Continuous optimization stage

[0059] a) Update the model every 10 minutes when at rest;

[0060] b) Updated every 30 minutes while in motion;

[0061] c) When D>0.35, rescan and calibrate.

[0062] In the dynamic compensation stage (3), the following optimization is performed based on the equivalent point coordinates (x,y,z):

[0063] (a) Left and right channel balance compensation:

[0064] Calculate the left and right gain adjustment amounts:

[0065] ΔG left =0.1×(xx) center );

[0066] ΔG right =-0.1×(xx) center );

[0067] Where x center =0 indicates the center of symmetry between the left and right sides of the carriage;

[0068] (b) Front and rear sound field delay calibration:

[0069] Calculate the additional delay of the speaker:

[0070]

[0071] Where y ref = -0.2m is the reference position, and c is the speed of sound;

[0072] (c) High-frequency reflection intensity control:

[0073] Adjusting high-frequency equalization based on the z-coordinate:

[0074]

[0075] It operates in the frequency band above 4kHz;

[0076] The optimization is performed after the compensation matrix is ​​calculated, and the final driving parameters are:

[0077] Front left speaker:

[0078] G FL =(G 250Hz +G 1kHz )+2×ΔG left +EQ high ;

[0079] Front right speaker:

[0080] G FR =(G 250Hz +G 1kHz )+2×ΔG right +EQ high ;

[0081] Rear left speaker:

[0082] G RL =(G 63Hz +G 4kHz)+EQ high ;

[0083] Rear right speaker:

[0084] G RR =(G 63Hz +G 4kHz )+EQ high ;

[0085] t final =t base +[0,0,0,Δt rear ];

[0086] Corresponding to the delay of the front left, front right, back left, and back right channels.

[0087] Configure a dynamic update strategy:

[0088] The acoustic environment is rescanned every 10 minutes when the vehicle is stationary; it is updated every 30 minutes when the vehicle is in motion; an emergency update is triggered immediately when a change in seat pressure distribution exceeding 15% or a sudden change in temperature and humidity (ΔT>10℃ or ΔRH>20%) is detected.

[0089] The beneficial effects of this invention are as follows:

[0090] This invention achieves five major breakthroughs through multi-sensor fusion acoustic fingerprint technology:

[0091] First, the multi-zone high-fidelity in-vehicle sound reinforcement system ensures audio stability across multiple zones within the vehicle. This results in revolutionary improvements in frequency response stability under all operating conditions. In a fully loaded scenario, low-frequency fluctuations are compressed from -6dB in traditional systems to ±1.5dB (a 300% improvement), mid-frequency fluctuations are reduced from +4dB to ±1.2dB when the trunk is fully loaded (a 233% optimization), and sound image drift caused by drastic temperature and humidity changes is sharply reduced from ±15° to ±3° (a 400% improvement). The core of this system lies in the Occup coefficient's dynamic compensation for load changes and the ΔE factor's precise calibration of sound velocity drift.

[0092] Secondly, the material adaptive optimization capability is significantly enhanced. Through the dual-parameter joint judgment mechanism of RT60 reverberation time and decay slope, it can intelligently identify velvet (α = 0.25 trigger mid-frequency +3dB) or leather material (α = 0.12 trigger high-frequency -2dB), which improves the clarity of human voices by 52% in the velvet environment and the PESQ score from 2.8 to 4.3. FFT harmonic analysis verifies that the separation of instruments increases by 40% in the leather environment.

[0093] Third, the millisecond-level dynamic response capability completely solves the real-time problem, reducing the static modeling time from 3.2 seconds to 1.8 seconds and the emergency update response speed to 0.5 seconds. Combined with the anti-vibration design, it automatically switches the cache model when the acceleration is >0.3g, making the availability rate of bumpy roads exceed 99%. The Q value dynamic adjustment function further suppresses the vibration frequency response fluctuation within 2dB.

[0094] This invention innovatively achieves sound field spatial reconstruction, with equivalent point coordinates (x, y, z) driving three-dimensional optimization: the X-axis coordinate controls the left and right gain difference through the ΔG_left / right parameter, compressing the sound image positioning error to within ±3°; the Y-axis coordinate is calculated by Δt_rear, and the speaker delay is completed within 10ms to reconstruct the sound field forward; the Z-axis coordinate controls the EQ_high value according to threshold partitions, improving the high-frequency listening consistency by 40%, such as automatically attenuating by 2dB when the skylight is open.

[0095] The cost and reliability advantages are equally significant. The reuse of seat pressure / temperature and humidity sensors reduces the incremental cost of the system by 70% compared to traditional solutions. The fault self-checking mechanism triggers recalibration when the model deviation D > 0.35, reducing the after-sales repair rate by 35%. The automotive-grade design further guarantees a 15-year service life across the entire temperature range of -40℃ to 85℃.

[0096] Verified in real vehicles, this solution maintains a bass response fluctuation of ±1.5dB, a sound field center offset of less than 0.1m, and a speech intelligibility MOS value of 4.1 under winter high-speed full-load conditions, compared to only 2.3 for traditional systems. The overall sound quality score is improved by 47%, marking a generational leap in in-vehicle audio adaptive technology. Attached Figure Description

[0097] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0098] Appendix Figure 1 This is a schematic diagram of the overall architecture of the present invention;

[0099] Appendix Figure 2 This is a schematic diagram of the interior layout of the vehicle according to the present invention.

[0100] Appendix Figure 3 This is a schematic diagram of the sensor of the present invention. Detailed Implementation

[0101] Example 1:

[0102] See appendix Figure 1 To be continued Figure 3A multi-zone high-fidelity vehicle sound reinforcement system, comprising a loudspeaker, including:

[0103] Ultrasonic transmitter array: located at the four corners of the carriage ceiling, configured to transmit linear sweep signals from 20kHz to 40kHz;

[0104] Microphone array: Distributed in the A-pillar, B-pillar, C-pillar and the middle of the roof of the vehicle to capture reflected sound waves inside the vehicle;

[0105] Pressure and environmental sensors: These are installed inside the seats to detect the distribution of occupants and the temperature and humidity of the vehicle interior.

[0106] Signal processing module: Constructs a three-dimensional acoustic model of the carriage by using the time difference of sound wave flight and calculates the sound absorption coefficient α. Generates dynamic equalization parameters based on the occup factor Occup and the temperature and humidity offset ΔE.

[0107] Audio output module: Applying dynamic equalization parameters to drive at least 8 full-range speakers in a distributed layout, with the front sound field speakers embedded in the dashboard and front doors, and the rear sound field speakers embedded in the rear doors and rear shelf;

[0108] The occupancy factor Occup is defined as the ratio of the total pressure sensor weight to 150kg, with an upper limit of 1. The temperature and humidity offset ΔE is calculated using the formula: ΔE=(T-25) / 10+(RH-50) / 20, where T is the current temperature and RH is the current humidity.

[0109] Ultrasonic transmitter assembly:

[0110] It employs Gold code spread spectrum modulation technology with a chip length of 127 bits;

[0111] The launch sequence starts 500ms after the doors are closed, and is triggered sequentially in the order of front left → front right → rear left → rear right of the roof, with an interval of 50±5ms between each adjacent launch.

[0112] The sweep frequency signal satisfies the time-frequency function relationship: the frequency increases linearly from 20kHz to 40kHz, with a duration of 100ms.

[0113] The discretization rule for the occup coefficient is as follows:

[0114] When the total pressure sensor load is less than 20 kg, Occup = 0, indicating an unloaded state.

[0115] When 20kg ≤ total < 150kg, Occup = 0.5, indicating a partial load condition;

[0116] When the total weight is ≥150kg, Occup = 1, indicating a fully loaded state.

[0117] The dynamic equilibrium parameters are generated through a compensation matrix:

[0118]

[0119] Among them, α is the sound absorption coefficient of the material, K is the normalization coefficient with a range of 0.8-1.2, and ΔE is the temperature and humidity compensation factor, the value of which is calculated from the deviation of environmental parameters from the reference conditions of 25℃ and 50%RH.

[0120] The 4×3 compensation matrix is ​​used to solve the frequency response distortion problem under different materials / loads / temperature and humidity conditions, the normalization coefficient K is used to prevent over-compensation from causing sound field distortion, and the ΔE temperature and humidity compensation is used to offset the effect of air density changes on sound speed.

[0121] Also includes:

[0122] The vibration interference suppression unit includes:

[0123] a) A three-axis accelerometer installed below the center console to monitor vehicle vibration intensity in real time;

[0124] b) Vibration response module: when the vertical acceleration > 0.3g and lasts for 0.1 seconds, modeling is stopped and the cached model is called;

[0125] c) Smoothing control module: when vibration lasts for more than 5 seconds, the equalizer Q value is reduced from 10 to 3 to reduce parameter sensitivity.

[0126] The sound absorption coefficient α of a material is determined by a combination of two parameters:

[0127] First, measure the reverberation time RT60 in the 200Hz-5kHz frequency band;

[0128] When RT60 ≥ 0.4 seconds and the attenuation slope of 500Hz-2kHz < -2.5dB / octave, it is determined to be a fleece material with α = 0.25;

[0129] When RT60 < 0.4 seconds and the decay slope ≥ -2.5dB / octave, it is determined to be leather material α = 0.12.

[0130] The attenuation slope is calculated using the rate of change of sound pressure level of the swept signal in the 500Hz-2kHz frequency band:

[0131]

[0132] Acoustic model self-verification mechanism execution: After each scan, the Euclidean distance D between the current model and the reference template is calculated;

[0133]

[0134] If D > 0.35, a rescan is triggered to ensure model validity;

[0135] If D > 0.35 twice consecutively, switch to the default mode and generate fault code 0xE2 to guide the rapid location of sensor faults.

[0136] Example 2:

[0137] An adaptive method for vehicle acoustic environment based on the system includes the following steps:

[0138] (1) Environment Triggering Phase

[0139] When a door closing signal is detected, ultrasonic scanning is initiated after a 500ms delay;

[0140] (2) Acoustic modeling stage

[0141] a) The ultrasonic transmitter group transmits 20-40kHz sweep frequency signals in the order of front left → front right → rear left → rear right.

[0142] b) The microphone array collects the reflected waves and calculates the time difference of sound wave flight Δt;

[0143] c) Construct an equivalent three-dimensional acoustic model:

[0144] Define transmitter coordinates:

[0145] T1=(x1,y1,z1), T2=(x2,y2,z2),

[0146] T3=(x3,y3,z3), T4=(x4,y4,z4);

[0147] Establish a system of distance difference equations:

[0148]

[0149] The equivalent point coordinates (x, y, z) are solved using the least squares method, where Δt12 = t1 - t2, Δt13 = t1 - t3, Δt14 = t1 - t4, c is the temperature and humidity compensated sound velocity, c = 340 × (1 + 0.006 × (T - 25)) × (1 + 0.0012 × (RH - 50)), and t1, t2, t3, and t4 are the flight times of the four ultrasonic waves from the transmitters T1, T2, T3, and T4 to the microphone array.

[0150] d) Calculate the sound absorption coefficient α:

[0151] When RT60 ≥ 0.4 seconds and the attenuation slope of 500Hz-2kHz < -2.5dB / octave, it is determined to be a fleece material with α = 0.25;

[0152] When RT60 < 0.4 seconds and the decay slope ≥ -2.5dB / octave, it is determined to be leather material α = 0.12;

[0153] (3) Dynamic compensation stage

[0154] Input parameters α, Occup, ΔE to the compensation matrix:

[0155]

[0156] Adjusting speaker frequency response: The front sound field focuses on sound image localization, while the rear sound field focuses on reverberation compensation;

[0157] (4) Continuous optimization stage

[0158] a) Update the model every 10 minutes when at rest;

[0159] b) Updated every 30 minutes while in motion;

[0160] c) When D>0.35, rescan and calibrate.

[0161] In the dynamic compensation stage (3), the following optimization is performed based on the equivalent point coordinates (x,y,z):

[0162] (a) Left and right channel balance compensation:

[0163] Calculate the left and right gain adjustment amounts:

[0164] ΔG left =0.1×(xx) center );

[0165] ΔG right =-0.1×(xx) center );

[0166] Where x center =0 indicates the center of symmetry between the left and right sides of the carriage;

[0167] (b) Front and rear sound field delay calibration:

[0168] Calculate the additional delay of the speaker:

[0169]

[0170] Where y ref = -0.2m is the reference position, and c is the speed of sound;

[0171] (c) High-frequency reflection intensity control:

[0172] Adjusting high-frequency equalization based on the z-coordinate:

[0173]

[0174] It operates in the frequency band above 4kHz;

[0175] The optimization is performed after the compensation matrix is ​​calculated, and the final driving parameters are:

[0176] Front left speaker:

[0177] G FL =(G 250Hz +G 1kHz )+2×ΔG left +EQ high ;

[0178] Front right speaker:

[0179] G FR =(G 250Hz +G 1kHz )+2×ΔG right +EQ high ;

[0180] Rear left speaker:

[0181] G RL =(G 63Hz +G 4kHz )+EQ high ;

[0182] Rear right speaker:

[0183] G RR =(G 63Hz +G 4kHz )+EQ high ;

[0184] t final =t base +[0,0,0,Δt rear ];

[0185] Corresponding to the delay of the front left, front right, back left, and back right channels.

[0186] Configure a dynamic update strategy:

[0187] The acoustic environment is rescanned every 10 minutes when the vehicle is stationary; it is updated every 30 minutes when the vehicle is in motion; an emergency update is triggered immediately when a change in seat pressure distribution exceeding 15% or a sudden change in temperature and humidity (ΔT>10℃ or ΔRH>20%) is detected.

[0188] Example 3:

[0189] Specific implementation examples of the system of this invention are as follows:

[0190] System initialization and hardware deployment

[0191] Ultrasonic transmitter assembly:

[0192] Transmitting modules are installed at the four corners of the carriage ceiling (coordinates T1(0.3,0.6,1.8), T2(0.3,-0.6,1.8), T3(-0.8,0.6,1.8), T4(-0.8,-0.6,1.8, unit: meters). Gold code spread spectrum modulation (127-bit code length) is used. Function: To transmit a 20-40kHz linear sweep frequency signal, utilizing the short wavelength (6.8cm@5kHz) of high-frequency sound waves to accurately detect small objects.

[0193] Microphone array:

[0194] Eight MEMS microphones (dynamic range 120dB) are placed in the A / B / C pillars and the middle of the ceiling. Principle: The reflection path is calculated using the time difference of arrival (TDOA) of sound waves, with a positioning accuracy of ±1.5cm.

[0195] Sensor networks:

[0196] The seat incorporates a pressure sensor (range 0-100kg) to monitor occupant distribution, and a temperature and humidity sensor (accuracy ±0.5℃) to collect environmental parameters. Technical details: Occup coefficient Occup=∑W_i / 150 (upper limit 1), ΔE=(T-25) / 10+(RH-50) / 20, quantifying the effect of air density on the speed of sound.

[0197] 2. Acoustic Modeling Stage (Core Innovation)

[0198] Step a: Ultrasonic scanning

[0199] Triggering mechanism: Activated 500ms after the car door closes, transmitting signals in the following sequence: front left → front right → rear left → rear right, with intervals of 50±5ms. Function: To avoid interference from door opening and closing vibrations and ensure signal stability.

[0200] Principle: Linear frequency sweep covers the frequency band sensitive to the human ear, and multipath interference is suppressed by a matched filter (processing gain 21dB).

[0201] Step b: Processing reflected waves

[0202] Flight time calculation:

[0203] The microphone array records the arrival times t1 to t4 of the sound waves from transmitters T1 to T4, and the time difference Δt is calculated. 12 = t1-t2, etc. Technical details: A cross-correlation algorithm is used to improve the accuracy of time difference measurement (resolution 0.1μs).

[0204] Step c: Solve for the equivalent point coordinates;

[0205] The purpose of constructing the equation system is to simplify the carriage into an acoustically equivalent reflection point (x, y, z), and to characterize the energy center of the overall sound field.

[0206] X-axis: Left and right balance (-0.5 to +0.5 m);

[0207] Y-axis: Front and back distribution (-1.0~0m);

[0208] Z-axis: Ceiling reflection intensity (0.5~1.5m);

[0209] Solution algorithm:

[0210] Levenberg-Marquardt nonlinear optimization was adopted, and convergence was achieved within 10 iterations (DSP computing power consumption <50MIPS);

[0211] Step d: Determining the sound absorption coefficient α

[0212] Reverberation time RT60 measurement:

[0213] A pulse signal with a cutoff frequency of 40kHz is transmitted, and an attenuation curve from 200Hz to 5kHz is fitted. Principle: The porous structure of velvet prolongs reverberation, while leather accelerates attenuation.

[0214] 3. Dynamic Compensation Phase (Multi-dimensional Optimization)

[0215] Matrix coefficient design principle:

[0216] This was obtained through regression analysis of 2000 sets of measured data from train carriages, for example:

[0217] The first row [0.8, -0.2, 0.1]: Low-frequency gain is positively correlated with load and negatively correlated with temperature;

[0218] Line 3 [0.2, 0.6, -0.3]: Mid-frequency sensitivity to velvet material (α↑);

[0219] Normalization coefficient K: dynamically adjusted based on historical frequency response smoothness (0.8-1.2) to prevent instantaneous overcompensation.

[0220] Anti-interference and self-verification mechanism

[0221] Vibration response:

[0222] When the triaxial accelerometer detects a vertical acceleration > 0.3g, the cache model is immediately switched. Technical details: Moving average filtering (50ms window) is used to suppress false triggering.

[0223] Q-value dynamic adjustment:

[0224] When the vibration lasts for more than 5 seconds, the equalizer Q value drops from 10 to 3. Effect: Reduces frequency response fluctuation from >6dB to <2dB.

[0225] Thus far, the description of the above embodiments has been provided for illustrative and descriptive purposes. This is not intended to be exhaustive or limiting of the present disclosure. Individual elements or features of particular embodiments are generally not limited to those particular embodiments, but may be interchanged and used in selected embodiments where applicable, even if not specifically shown or described. In many respects, the same elements or features may also be varied. Such variations are not considered a departure from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

[0226] Example embodiments are provided so that this disclosure will become thorough and will fully convey the scope to those skilled in the art. Numerous details, such as examples of specific parts, apparatus, and methods, are set forth to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that the specific details are not required, and the example embodiments may be implemented in many different forms, neither of which should be construed as limiting the scope of this disclosure. In some example embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0227] Technical terms are used herein for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a” and “the” as used herein may also refer to the plural forms. The terms “comprising” and “having” are inclusive and therefore specify the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or additional having of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. Unless expressly indicated in the order of execution, the method steps, processes, and... described herein...

[0228] The operation is not to be interpreted as necessarily needing to be performed in the specific order discussed and shown. It should also be noted that...

[0229] It is understood that additional or optional steps may be taken.

Claims

1. A multi-zone high-fidelity vehicle-mounted sound reinforcement system, capable of adapting to the vehicle's acoustic environment, and featuring loudspeakers, characterized in that... Include: Ultrasonic transmitter array: located at the four corners of the carriage ceiling, configured to transmit linear sweep signals from 20kHz to 40kHz; Microphone array: Distributed in the A-pillar, B-pillar, C-pillar and the middle of the roof of the vehicle to capture reflected sound waves inside the vehicle; Pressure and environmental sensors: These are installed inside the seats to detect the distribution of occupants and the temperature and humidity of the vehicle interior. Signal processing module: Constructs a three-dimensional acoustic model of the carriage by using the time difference of sound wave flight and calculates the sound absorption coefficient α. Generates dynamic equalization parameters based on the occup factor Occup and the temperature and humidity offset ΔE. Audio output module: Applying dynamic equalization parameters to drive at least 8 full-range speakers in a distributed layout, with the front sound field speakers embedded in the dashboard and front doors, and the rear sound field speakers embedded in the rear doors and rear shelf; The occupancy factor Occup is defined as the ratio of the total pressure sensor weight to 150kg, with an upper limit of 1. The temperature and humidity offset ΔE is calculated using the formula: ΔE=(T-25) / 10+(RH-50) / 20, where T is the current temperature and RH is the current humidity.

2. The system as described in claim 1, characterized in that... The ultrasonic transmitter group: It employs Gold code spread spectrum modulation technology with a chip length of 127 bits; The launch sequence starts 500ms after the doors are closed, and is triggered sequentially in the order of front left → front right → rear left → rear right of the roof, with an interval of 50±5ms between each adjacent launch. The sweep frequency signal satisfies the time-frequency function relationship: the frequency increases linearly from 20kHz to 40kHz, with a duration of 100ms.

3. The system as described in claim 1, characterized in that... The discretization rule for the occup coefficient is as follows: When the total pressure sensor load is less than 20 kg, Occup = 0, indicating an unloaded state. When 20kg ≤ total < 150kg, Occup = 0.5, indicating a partial load condition; When the total weight is ≥150kg, Occup = 1, indicating a fully loaded state.

4. The system as described in claim 1, characterized in that... The dynamic equilibrium parameters are generated through a compensation matrix: Among them, α is the sound absorption coefficient of the material, K is the normalization coefficient with a range of 0.8-1.2, and ΔE is the temperature and humidity compensation factor, the value of which is calculated from the deviation of environmental parameters from the reference conditions of 25℃ and 50%RH. The 4×3 compensation matrix is ​​used to solve the frequency response distortion problem under different materials / loads / temperature and humidity conditions, the normalization coefficient K is used to prevent over-compensation from causing sound field distortion, and the ΔE temperature and humidity compensation is used to offset the effect of air density changes on sound speed.

5. The system as described in claim 1, characterized in that... Include: The vibration interference suppression unit includes: a) A three-axis accelerometer installed below the center console to monitor vehicle vibration intensity in real time; b) Vibration response module: when the vertical acceleration > 0.3g and lasts for 0.1 seconds, modeling is stopped and the cached model is called; c) Smoothing control module: when vibration lasts for more than 5 seconds, the equalizer Q value is reduced from 10 to 3 to reduce parameter sensitivity.

6. The system as described in claim 1, characterized in that... The sound absorption coefficient α of a material is determined by a combination of two parameters: First, measure the reverberation time RT60 in the 200Hz-5kHz frequency band; When RT60 ≥ 0.4 seconds and the attenuation slope of 500Hz-2kHz < -2.5dB / octave, it is determined to be a fleece material with α = 0.25; When RT60 < 0.4 seconds and the decay slope ≥ -2.5dB / octave, it is determined to be leather material α = 0.

12. The attenuation slope is calculated using the rate of change of sound pressure level of the swept signal in the 500Hz-2kHz frequency band:

7. The system according to claim 1, characterized in that: Acoustic model self-verification mechanism execution: After each scan, the Euclidean distance D between the current model and the reference template is calculated; If D > 0.35, a rescan is triggered to ensure model validity; If D > 0.35 twice consecutively, switch to the default mode and generate fault code 0xE2 to guide the rapid location of sensor faults.

8. A vehicle-mounted acoustic environment adaptive method based on the system described in claims 1-7, characterized in that... Includes the following steps: (1) Environment Triggering Phase When a door closing signal is detected, ultrasonic scanning is initiated after a 500ms delay; (2) Acoustic modeling stage a) The ultrasonic transmitter group transmits 20-40kHz sweep frequency signals in the order of front left → front right → rear left → rear right. b) The microphone array collects the reflected waves and calculates the time difference of sound wave flight Δt; c) Construct an equivalent three-dimensional acoustic model: Define transmitter coordinates: T1=(x1,y1,z1), T2=(x2,y2,z2), T3=(x3,y3,z3), T4=(x4,y4,z4); Establish a system of distance difference equations: The equivalent point coordinates (x, y, z) are solved using the least squares method, where Δt12 = t1 - t2, Δt13 = t1 - t3, Δt14 = t1 - t4, c is the temperature and humidity compensated sound velocity, c = 340 × (1 + 0.006 × (T - 25)) × (1 + 0.0012 × (RH - 50)), and t1, t2, t3, and t4 are the flight times of the four ultrasonic waves from the transmitters T1, T2, T3, and T4 to the microphone array. d) Calculate the sound absorption coefficient α: When RT60 ≥ 0.4 seconds and the attenuation slope of 500Hz-2kHz < -2.5dB / octave, it is determined to be a fleece material with α = 0.25; When RT60 < 0.4 seconds and the decay slope ≥ -2.5dB / octave, it is determined to be leather material α = 0.12; (3) Dynamic compensation stage Input parameters α, Occup, ΔE to the compensation matrix: Adjusting speaker frequency response: The front sound field focuses on sound image localization, while the rear sound field focuses on reverberation compensation; (4) Continuous optimization stage a) Update the model every 10 minutes when at rest; b) Updated every 30 minutes while in motion; c) When D>0.35, rescan and calibrate.

9. The vehicle-mounted acoustic environment adaptive method as described in claim 8, characterized in that... In the dynamic compensation stage (3), the following optimization is performed based on the equivalent point coordinates (x,y,z): (a) Left and right channel balance compensation: Calculate the left and right gain adjustment amounts: ΔG left =0.1×(x-x center ); ΔG right =-0.1×(x-x center ); Where x center =0 indicates the center of symmetry between the left and right sides of the carriage; (b) Front and rear sound field delay calibration: Calculate the additional delay of the speaker: Where y ref = -0.2m is the reference position, and c is the speed of sound; (c) High-frequency reflection intensity control: Adjusting high-frequency equalization based on the z-coordinate: It operates in the frequency band above 4kHz; The optimization is performed after the compensation matrix is ​​calculated, and the final driving parameters are: Front left speaker: G FL =(G 250Hz +G 1kHz )+2×ΔG left +EQ high ; Front right speaker: G FR =(G 250Hz +G 1kHz )+2×ΔG righ t+EQ high ; Rear left speaker: G RL =(G 63Hz +G 4kHz )+EQ high ; Rear right speaker: G RR =(H 63Hz +G 4kHz )+EQ high ; t final =t base +[0,0,0,Δt rear ]; Corresponding to the delay of the front left, front right, back left, and back right channels.

10. The vehicle-mounted acoustic environment adaptive method as described in claim 8, characterized in that... Configure a dynamic update strategy: The acoustic environment is rescanned every 10 minutes when the vehicle is stationary; it is updated every 30 minutes when the vehicle is in motion; an emergency update is triggered immediately when a change in seat pressure distribution exceeding 15% or a sudden change in temperature and humidity (ΔT>10℃ or ΔRH>20%) is detected.

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