Earphone quality detection method and system

Abstract

The invention relates to the technical field of earphones, in particular to an earphone quality detection method and system, and the method comprises the steps: checking the assembly integrity of an earphone, sending the earphone into a detection region, and calibrating a reference microphone; applying a predetermined standard electric signal to a to-be-tested earphone core in the earphone, and driving the to-be-tested earphone core to generate a corresponding first acoustic signal; acoustically coupling the reference microphone with the earphone core to be tested, acquiring a second acoustic signal corresponding to the first acoustic signal, and converting the second acoustic signal into a first electric response signal; the method comprises the following steps: acoustically coupling a to-be-tested earphone core with a to-be-tested microphone built in the earphone, acquiring a first acoustic signal, and converting the first acoustic signal into a second electric response signal; and constructing an acoustoelectric closed loop by taking the first electric response signal as acoustic output data and the second electric response signal as acoustic input data, and evaluating the quality of the earphone according to the acoustoelectric closed loop to obtain a quality detection result. According to the invention, by constructing an acoustoelectric closed loop and combining analysis of amplitude stability and phase stability, the earphone quality detection accuracy is effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of earphones, in particular to an earphone quality detection method and system. BACKGROUND

[0002] The earphone quality detection method generally refers to a series of methods for detecting the performance, sound quality and structural integrity of earphones, which aims to ensure that the earphones meet the predetermined quality standards during production and use, including but not limited to the accuracy of audio output, the stability of sound, and the durability of earphones, etc. With the increasing demand for audio product quality from consumers, earphone quality detection methods have become crucial in earphone manufacturing and testing.

[0003] At present, there are various earphone quality detection methods on the market, among which the common ones include signal collection based on acoustic sensors, analysis of earphone electrical response signals, and environmental adaptability testing through specific test equipment. However, the application of these existing technologies usually has certain limitations, often relying on static frequency response analysis, which cannot effectively capture the instantaneous fluctuations that may occur during actual use of earphones, and usually relies on a single frequency response or simple signal gain adjustment, making it difficult to cope with complex acoustoelectric closed-loop evaluation. Some current earphone detection methods lack real-time adjustment and optimization functions, and cannot dynamically adjust test parameters according to real-time feedback, which limits the flexibility and accuracy of the detection process.

[0004] Therefore, a more accurate earphone quality detection method and system are needed. SUMMARY

[0005] In view of at least one of the above technical problems, the present application provides an earphone quality detection method and system, which adopts the construction of an acoustoelectric closed loop and combines amplitude stability and phase stability analysis to realize more accurate, comprehensive and dynamic earphone performance evaluation, thereby improving the accuracy and reliability of detection.

[0006] The present application provides an earphone quality detection method, comprising the following steps: S10: Check the assembly integrity of the earphone and send it to the detection area, and calibrate the reference microphone; S20: Apply a predetermined standard electrical signal to the earphone to be tested, drive the earphone to be tested to generate a corresponding first acoustic signal in a free field or a coupling cavity; S30: Acoustically couple the reference microphone with the earphone to be tested, under the driving of the standard electrical signal, collect a second acoustic signal corresponding to the first acoustic signal through the reference microphone, and convert the second acoustic signal into a first electrical response signal; S40: Using the earphone chip under test as a sound source, acoustically couple it with the microphone under test built into the earphone, collect the first acoustic signal through the microphone under test, and convert the first acoustic signal into a second electrical response signal; S50: Construct an acoustic-electric closed loop using the first electrical response signal as acoustic output data and the second electrical response signal as acoustic input data, evaluate the quality of the headphones based on the acoustic-electric closed loop, and obtain the quality test results.

[0007] Further, in step S20, driving the earphone chip under test to generate a corresponding first acoustic signal in a free field or coupling cavity includes: A standard electrical signal of predetermined frequency and amplitude is applied to the earphone core under test, and the amplitude and frequency of the standard electrical signal are adjusted to control the diaphragm vibration of the earphone core under test, thereby generating a corresponding acoustic signal. In a free field, the first acoustic signal of the earphone core under test is generated by propagating through the air based on the acoustic signal; In the coupling cavity, the acoustic signal generated by the earphone chip under test is guided to the cavity of the coupling cavity to generate the first acoustic signal.

[0008] Further, in step S30, acoustically coupling the reference microphone to the earphone core under test includes: The reference microphone is placed on the acoustic output path of the earphone core under test, with the receiving end of the reference microphone facing the diaphragm or sound wave output end of the earphone core under test, thus forming effective acoustic coupling.

[0009] Further, in step S30, converting the second acoustic signal into a first electrical response signal includes: Set the filtering parameters and perform frequency-selective filtering on the acquired second acoustic signal to preserve the audio range required for headphone testing; Set the gain parameter, adjust the gain of the filtered second acoustic signal, and convert the gain-adjusted second acoustic signal into an electrical signal; The electrical signal is subjected to time-frequency analysis to extract its frequency, amplitude, and phase information, and the data is processed to generate electrical signal data suitable for quality assessment. The electrical signal data is compared with a preset standard signal, and the gain parameter and the filtering parameter are adjusted in real time to generate the first electrical response signal.

[0010] Further, in step S50, constructing an acoustic-electric closed loop includes: Multiple frequency points are preset, and the amplitude and phase values ​​of the acoustic output data and the acoustic input data are simultaneously collected at the preset frequency points; Calculate the amplitude difference and phase difference between the acoustic output data and the acoustic input data at each frequency point; The amplitude difference is compared with a preset amplitude tolerance range, and the phase difference is compared with a preset phase tolerance range. When the amplitude difference at any of the frequency points exceeds the amplitude tolerance range or the phase difference exceeds the phase tolerance range, a parameter adjustment command is generated; Adjust the first electrical response signal or the second electrical response signal according to the parameter adjustment command to form an acoustic-electric closed loop.

[0011] Further, in step S50, evaluating the headphone quality based on the described acoustic-electric closed-loop method includes: The standard electrical signal is controlled to increase its amplitude in a stepwise manner at multiple frequency points, forming an amplitude step; At each amplitude step of each frequency point, the instantaneous amplitude fluctuation value and instantaneous phase jitter value of the second electrical response signal relative to the first electrical response signal are monitored and recorded; A time-domain stability analysis is performed on the instantaneous amplitude fluctuation value and the instantaneous phase jitter value, and their standard deviations on each amplitude step are calculated to obtain the amplitude stability index and the phase stability index, respectively. Analyze the variation patterns of the amplitude stability index and the phase stability index with frequency and amplitude, and determine the headphone quality based on these patterns.

[0012] Further, in step S50, the amplitude stability index and phase stability index are obtained, including: During the stabilization phase of each amplitude step, the instantaneous amplitude fluctuation value and the instantaneous phase jitter value are continuously collected with a fixed sampling window to form the original data sequence; Outlier detection is performed on each of the original data sequences. Outlier data points caused by external transient interference are identified and removed using the interquartile range method, generating the removed data. Linear interpolation is used to fill the gaps in the removed data, forming a purified amplitude fluctuation sequence and phase jitter sequence; Each amplitude fluctuation sequence is divided into multiple consecutive and partially overlapping amplitude analysis segments, and each phase jitter sequence is divided into multiple consecutive and partially overlapping phase analysis segments. Calculate the standard deviation of each amplitude analysis segment and each phase analysis segment to obtain the standard deviation set of amplitude segments and the standard deviation set of phase segments; Based on the set of standard deviations of the amplitude segments, their statistical characteristic values ​​are calculated to generate an amplitude stability index; based on the set of standard deviations of the phase segments, their statistical characteristic values ​​are calculated to generate a phase stability index.

[0013] Further, in step S50, its statistical characteristic values ​​are calculated, including: The median of the standard deviation set of the amplitude sub-segments or the standard deviation set of the phase sub-segments is taken as the benchmark stability characterizing the steady-state fluctuation level under the amplitude step. The upper quartile of the standard deviation set of the amplitude segment or the standard deviation set of the phase segment is taken as the peak stability characterizing the worst fluctuation case under the amplitude step. The baseline stability and the peak stability are weighted and summed according to a preset weight, and the result is used as the amplitude stability index or the phase stability index.

[0014] Further, in step S50, determining the quality of the headphones according to the aforementioned rule includes: With frequency as the horizontal axis and standard electrical signal amplitude as the vertical axis, the frequency amplitude plane is denoted as the frequency amplitude plane. The amplitude stability index and the phase stability index corresponding to each coordinate point are mapped into a two-dimensional stability vector. On the frequency amplitude plane, surface fitting is performed on all the two-dimensional stability vectors to obtain amplitude stability trend surface and phase stability trend surface, respectively; Calculate the gradient field of the amplitude stability trend surface and the gradient field of the phase stability trend surface; Identify regions in the gradient field whose modulus is greater than a preset sensitivity threshold, define them as performance-vulnerable regions, and record the location and range of the performance-vulnerable regions on the frequency amplitude plane; Based on the location and range, calculate the ratio of the total area of ​​all the performance-vulnerable regions to the frequency amplitude plane and the average value of the gradient magnitude within the performance-vulnerable regions, and record it as the rule; The quality of the headphones is determined based on the aforementioned rules.

[0015] The present invention also provides an earphone quality testing system, comprising: Check the calibration module, check the integrity of the headphone assembly and send it to the testing area, calibrate the reference microphone; The signal driving module applies a predetermined standard electrical signal to the earphone core under test in the earphone, driving the earphone core under test to generate a corresponding first acoustic signal in a free field or coupling cavity. The coupling conversion module acoustically couples the reference microphone to the earphone core under test. Driven by the standard electrical signal, the reference microphone acquires a second acoustic signal corresponding to the first acoustic signal and converts the second acoustic signal into a first electrical response signal. The earphone core under test is used as a sound source and acoustically coupled to the earphone's built-in microphone under test. The microphone under test acquires the first acoustic signal and converts the first acoustic signal into a second electrical response signal. An evaluation module is constructed, which uses the first electrical response signal as acoustic output data and the second electrical response signal as acoustic input data to build an acoustic-electric closed loop. The quality of the headphones is evaluated based on the acoustic-electric closed loop to obtain quality test results.

[0016] The technical solution of this invention can achieve the following technical effects: This invention significantly improves the accuracy and comprehensiveness of headphone testing by constructing an acoustic-electric closed loop and combining comprehensive analysis of amplitude and phase stability. By analyzing the amplitude difference, phase difference, and instantaneous fluctuations between the headphone output signal and input signal in the time domain, it can comprehensively evaluate the dynamic response of the headphone in actual use. By dynamically adjusting the gain and filtering parameters during the testing process, it enhances the flexibility and adaptability of the testing process and significantly improves the reliability of the testing.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0018] 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 recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the headphone quality testing method in an embodiment of the present invention; Figure 2 This is a schematic diagram of the process of driving the earphone chip under test to generate a corresponding first acoustic signal in a free field or coupling cavity in an embodiment of the present invention; Figure 3 This is a schematic diagram of the process of converting the second acoustic signal into a first electrical response signal according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the process for constructing an acoustic-electric closed loop in an embodiment of the present invention; Figure 5 This is a schematic diagram of the process for evaluating headphone quality based on the acoustic-electric closed-loop in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the process of obtaining the amplitude stability index and the phase stability index in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] This invention provides, for example Figures 1 to 6 The headphone quality testing method shown includes the following steps: S10; Check the integrity of the headphone assembly and send it to the testing area to calibrate the reference microphone; Check the integrity of the headphone assembly to ensure that all components (such as the headphone core, microphone, shell, etc.) are correctly assembled. This can be done through visual inspection and mechanical inspection tools to check that the headphone has no defects or looseness during the production process; The calibration of the reference microphone is to ensure that it can accurately reflect the changes in acoustic signals during the subsequent signal acquisition process. As a reference benchmark, the calibration can be performed by driving the reference microphone with a preset standard signal (such as an electrical signal of a certain frequency and amplitude) to ensure that its frequency response and sensitivity meet the testing requirements.

[0023] S20: A predetermined standard electrical signal is applied to the earphone driver under test in the earphone. The frequency and amplitude of the signal can be adjusted to ensure that the diaphragm of the earphone driver vibrates as expected and generates the corresponding acoustic signal. The applied standard electrical signal can include sine wave signals of different frequencies in the range of 20Hz to 20kHz to simulate various audio signals that the earphone may encounter in actual use. When adjusting the amplitude, an appropriate amplitude range can be selected to ensure that the earphone driver generates an acoustic signal without distortion. The earphone driver under test is driven to generate the corresponding first acoustic signal in a free field (open environment) or a coupled cavity (closed test cavity), and the specific choice depends on the actual test requirements. The free field test can be used to detect the overall sound quality of the earphone, while the coupled cavity test can more accurately simulate the actual working environment of the earphone.

[0024] S30: Acoustically couple the reference microphone to the earphone core under test to ensure effective signal transmission between them. Driven by a standard electrical signal, the reference microphone acquires a second acoustic signal corresponding to the first acoustic signal and converts the second acoustic signal into a first electrical response signal. The reference microphone is positioned as precisely as possible on the sound wave path of the earphone output to capture the output signal of the earphone core to the greatest extent. A high-precision digital microphone can be selected for the reference microphone to ensure that the electrical response signal it acquires has high fidelity. In terms of acoustic coupling, a bracket-based or clamp-based fixing method can be used to ensure that the relative position and distance between the reference microphone and the earphone core remain stable, thereby improving the consistency of the test.

[0025] S40: Using the earphone chip under test as the sound source, acoustically couple it with the built-in microphone under test in the earphone. The microphone under test acquires the first acoustic signal and converts it into a second electrical response signal. A high-sensitivity built-in microphone (such as a high-quality condenser microphone) is selected to improve acquisition accuracy. The microphone placement should consider the actual wearing angle of the earphone to ensure accurate acquisition of the earphone's audio output during actual wear. By acquiring the dynamic characteristics of the internal signal of the earphone, data support is provided for subsequent quality assessment.

[0026] S50: Construct an acoustic-electric closed loop using the first electrical response signal as acoustic output data and the second electrical response signal as acoustic input data. Evaluate the quality of the headphones based on the acoustic-electric closed loop and obtain the quality test results.

[0027] Starting with an assembly integrity check of the headphones, ensuring there are no assembly defects or looseness during production, thus avoiding performance instability caused by assembly problems. Then, through precise signal input and acoustic signal acquisition, the headphones' performance in different environments is simulated. Furthermore, through acoustic coupling between the reference microphone and the microphone under test, the electrical response signal of the headphones is obtained. Using acoustic-electric closed-loop technology for feedback evaluation, not only is the frequency response of the headphones detected, but also its amplitude stability and phase stability are analyzed, thereby more comprehensively testing the performance of the headphones at various frequency bands and volumes.

[0028] In some embodiments of the present invention, such as Figure 2 As shown, in step S20, driving the earphone chip under test to generate a corresponding first acoustic signal in a free field or coupling cavity includes: A standard electrical signal of predetermined frequency and amplitude is applied to the earphone chip under test. This signal can be a basic waveform such as a sine wave or square wave, and its frequency range can cover the operating frequency band of the earphone. The amplitude and frequency of the standard electrical signal are adjusted according to different test requirements to control the diaphragm vibration of the earphone chip under test and generate corresponding acoustic signals. The frequency and amplitude of the standard electrical signal can be generated by a computer-controlled signal generator and driven by a power amplifier. To ensure the accuracy of the test, the amplitude of the standard electrical signal should cover the operating range of the earphone, while the frequency can cover different frequency ranges from low to high frequencies, which is convenient for comprehensively evaluating the performance of the earphone.

[0029] In a free field, the earphone chip under test is placed in an open test environment. The first acoustic signal of the earphone chip under test is generated based on the propagation of acoustic signals through the air. This simulates the performance of the earphone in daily use, especially the effect of the sound emitted by the earphone chip being transmitted to the ear through the air when the earphone is worn in the user's ear.

[0030] In the coupling cavity, the acoustic signal generated by the earphone chip under test is guided to the cavity body. The cavity design can effectively guide the acoustic signal generated by the earphone chip and transmit it to the reference microphone through the internal space of the coupling cavity to generate the first acoustic signal. The shape and volume of the cavity should be similar to the human ear canal to more realistically simulate the audio propagation path when the earphone is worn. The coupling cavity is equipped with a high-sensitivity microphone that can accurately capture and convert the acoustic signal generated by the earphone chip. Through precise acoustic coupling, high-fidelity data of the first acoustic signal emitted by the earphone chip can be obtained.

[0031] In some embodiments of the present invention, step S30, acoustically coupling the reference microphone to the earphone core under test, includes: A reference microphone is placed on the acoustic output path of the earphone chip under test, with the receiving end of the reference microphone facing the diaphragm or sound wave output end of the earphone chip under test, thus forming an effective acoustic coupling.

[0032] In traditional headphone quality testing, acoustic signals emitted by the headphone driver are typically acquired through simple distance settings or incomplete coupling. This approach can lead to inaccurate or biased signal acquisition, failing to fully reflect the actual sound quality characteristics of the headphone's output. This embodiment ensures efficient transmission and accurate acquisition of sound wave signals by precisely placing a reference microphone on the acoustic output path of the headphone driver. This not only improves signal acquisition accuracy but also reduces testing errors caused by improper distance or relative position between the microphone and the headphone driver. Through this effective acoustic coupling, the reference microphone can accurately capture every detail of the sound waves output by the headphone driver, ensuring that the acquired signal fully reflects the headphone's audio response and stability.

[0033] In some embodiments of the present invention, such as Figure 3As shown, in step S30, converting the second acoustic signal into a first electrical response signal includes: Set the filtering parameters to perform frequency selective filtering on the acquired second acoustic signal, preserving the audio range required for headphone testing; the filter type can be a bandpass filter or a bandstop filter, depending on the frequency range to be preserved or removed. A bandpass filter can effectively filter out signals within the headphone's operating range, while a bandstop filter can remove irrelevant noise or high-order harmonics to ensure the purity of the test signal.

[0034] The gain parameter is set to adjust the gain of the filtered second acoustic signal to bring its amplitude into a suitable range for subsequent electrical signal processing. The gain-adjusted second acoustic signal is then converted into an electrical signal. The gain adjustment process is achieved by adjusting the gain parameter, which can be achieved by hardware gain control (such as an amplifier) ​​or software gain adjustment (such as a digital signal processing algorithm). This ensures that the signal is not too strong, which would cause distortion, nor too weak, which would affect the accuracy of subsequent analysis. It also ensures that the gain remains consistent throughout the test to adapt to the output characteristics of different headphones.

[0035] Time-frequency analysis of electrical signals extracts their frequency, amplitude, and phase information, and data processing generates electrical signal data suitable for quality assessment. Time-frequency analysis methods can employ techniques such as short-time Fourier transform or wavelet transform to analyze signal changes in the time and frequency domains in real time. High-precision time-frequency analysis tools allow for simultaneous observation of signal amplitude and phase changes and their time-domain stability across multiple frequency components. This helps identify the headphone's response characteristics at different frequencies and potential distortion or phase mismatch issues.

[0036] The electrical signal data is compared with a preset standard signal, and the gain and filtering parameters are adjusted in real time to generate the first electrical response signal. By comparing the test signal with the standard signal, the frequency response, amplitude, and phase stability of the headphones are evaluated. If there is a deviation between the test signal and the standard signal, the gain and filtering parameters can be adjusted in real time to ensure the accuracy of the test. The comparison process can use error analysis algorithms (such as mean square error MSE or spectral distortion index) to quantify the difference between the electrical signal and the standard signal.

[0037] In some embodiments of the present invention, such as Figure 4 As shown, in step S50, constructing the acoustic-electric closed loop includes: Multiple frequency points are preset, and the amplitude and phase values ​​of acoustic output data and acoustic input data are collected synchronously at these frequency points. To improve the acquisition accuracy, multiple frequency points can be evenly distributed across the entire frequency range to ensure coverage of all audio performance of the headphones. Data acquisition can be carried out in conjunction with a high-precision microphone and the acquisition system to record the amplitude and phase data of each frequency point in real time.

[0038] Calculate the amplitude difference and phase difference between the acoustic output data and the acoustic input data at each frequency point. The calculation of amplitude difference and phase difference can be achieved through signal processing algorithms. For example, Fourier transform can be used to calculate the amplitude and phase at each frequency point, and then the amplitude difference and phase difference can be obtained through the difference formula. For each frequency point, such calculation ensures high data accuracy.

[0039] Compare the amplitude difference with the preset amplitude tolerance range, and at the same time compare the phase difference with the preset phase tolerance range; determine whether the test results of each frequency point meet the quality standards. If the amplitude difference or phase difference exceeds the preset tolerance range, it indicates that the headphones may have performance problems at that frequency point and parameter adjustments are required; the amplitude tolerance range and phase tolerance range should be set according to the headphone's design standards or industry standards.

[0040] When the amplitude difference at any frequency point exceeds the amplitude tolerance range or the phase difference exceeds the phase tolerance range, a parameter adjustment command is generated. The parameter adjustment command can include gain adjustment, dynamic adjustment of filter parameters, or phase compensation. Through real-time analysis and adjustment, the headphone performance can be finely optimized to ensure that it meets the design requirements under various test conditions.

[0041] Adjusting the first or second electrical response signal according to the parameter adjustment command forms an acoustic-electric closed loop, ensuring that the audio response of the headphones meets the quality requirements. This makes the performance of the headphones more stable and consistent across all frequency points, realizing the feedback mechanism of the acoustic-electric closed loop. It can not only correct the performance of the headphones, but also provide accurate data support for subsequent quality assessment.

[0042] In some embodiments of the present invention, such as Figure 5 As shown, in step S50, the headphone quality is evaluated based on the acoustic-electric closed-loop method, including: A standard electrical signal is controlled to increase its amplitude in a stepwise manner across multiple frequency points, forming an amplitude ladder. This simulates the performance of headphones at different volume levels, and the stability of the headphone response is observed. The amplitude ladder can be set through an automated control system, which can gradually increase the amplitude of the electrical signal at multiple frequency points (such as 20Hz, 100Hz, 1kHz, 5kHz, etc.). The step size of the amplitude increase can be set according to the response characteristics of the headphones. The amplitude increase method can be linear or logarithmic, depending on the test requirements.

[0043] At each amplitude step of each frequency point, the instantaneous amplitude fluctuation and instantaneous phase jitter of the second electrical response signal relative to the first electrical response signal are monitored and recorded. This can reflect the stability of the headphones at different volumes and their response characteristics in the time domain. The monitoring of amplitude fluctuation and phase jitter can be accomplished by a high-precision digital signal processing unit or a real-time analysis system. This can quickly analyze the instantaneous amplitude and phase of the signal and accurately record the fluctuation value at each test point, which helps to determine whether the headphones experience distortion or phase instability under various operating conditions.

[0044] Temporal stability analysis is performed on instantaneous amplitude fluctuations and instantaneous phase jitter values. The standard deviation of these values ​​at each amplitude step is calculated to obtain amplitude stability index and phase stability index, respectively. The smaller the standard deviation, the more stable the headphone performance. Temporal stability analysis can be performed using dedicated signal processing tools (such as FFT analyzers or time-domain analyzers) to calculate the standard deviation of amplitude fluctuations and phase jitter, helping to determine whether the headphone's performance at different amplitudes meets the design standards.

[0045] By analyzing the patterns of amplitude stability and phase stability indices as a function of frequency and amplitude, and by comprehensively understanding the dynamic performance of the headphones based on these patterns, including their stability changes at different frequencies and volumes, the quality of the headphones can be determined.

[0046] Based on the above embodiments, such as Figure 5 As shown, in step S50, the amplitude stability index and phase stability index are obtained, including: During the stabilization phase of each amplitude step, instantaneous amplitude fluctuation values ​​and instantaneous phase jitter values ​​are continuously collected with a fixed sampling window to form a raw data sequence for subsequent time-domain analysis and stability assessment. The size of the sampling window can be set as needed, and a fixed-length time window can be selected, such as 1 second or 10 milliseconds, to ensure that the collected data has sufficient time resolution and accuracy. The number of data points within the window should be set according to the frequency response characteristics and the system sampling rate to ensure that the collected data is complete and representative.

[0047] Outlier detection is performed on each original data sequence. The interquartile range (IQR) method is used to identify and remove outlier data points caused by external transient interference, generating the removed data. The IQR method identifies the location of extreme values ​​in the statistical distribution by calculating the quartiles of the data sequence and removes these outlier data points from the original data, avoiding the impact of abnormal fluctuations caused by noise or interference on the final analysis results.

[0048] To ensure the continuity and integrity of the data, linear interpolation is used to fill the gaps in the removed data, forming a purified amplitude fluctuation sequence and phase jitter sequence. The linear interpolation method calculates the interpolation point at the gap based on the values ​​of two consecutive valid data points, thereby smoothing the data and avoiding the impact of missing data on subsequent analysis.

[0049] Each amplitude fluctuation sequence is divided into multiple continuous and partially overlapping amplitude analysis segments, and each phase jitter sequence is divided into multiple continuous and partially overlapping phase analysis segments. Long-term fluctuation data is decomposed into multiple smaller segments to allow for more detailed analysis of the data characteristics within each segment. Amplitude fluctuation sequences and phase jitter sequences can be divided into overlapping segments by setting a fixed-size segment window and sliding it in a certain step each time. Overlapping regions can effectively improve the continuity and completeness of data analysis.

[0050] Calculate the standard deviation of each amplitude analysis segment and phase analysis segment to obtain the standard deviation set of amplitude segment and the standard deviation set of phase segment. Standard deviation is an important indicator for measuring the degree of data fluctuation and can effectively reflect the stability within each analysis segment. A lower standard deviation value means that the amplitude or phase change within the segment is small, indicating that the headphone's performance in that frequency band is stable. A higher standard deviation value indicates that the fluctuation within the frequency band is large, and there may be distortion or instability.

[0051] Based on the standard deviation set of amplitude segments, its statistical characteristic value is calculated to generate an amplitude stability index; based on the standard deviation set of phase segments, its statistical characteristic value is calculated to generate a phase stability index; statistical analysis methods such as mean and variance can be used to calculate amplitude or phase stability indices, providing a reliable basis for headphone quality assessment and accurately reflecting the amplitude and phase stability of the headphone throughout the testing process.

[0052] Based on the above embodiments, step S50, calculating its statistical characteristic values, includes: The median of either the amplitude sub-segment standard deviation set or the phase sub-segment standard deviation set is taken. As the central value of the data set, the median serves as a benchmark stability characterizing the steady-state fluctuation level under that amplitude step. By selecting the median, extreme data points such as outliers or noise interference can be ignored, making the calculation results more representative. The standard deviation set can be sorted using a ranking method, and the middle value can be taken as the median. If the standard deviation set contains an even number of data points, the median is the average of the two middle data points.

[0053] The upper quartile is taken from the set of standard deviations of the amplitude sub-segments or the set of standard deviations of the phase sub-segments. The upper quartile is the data value ranked 75th in the dataset. It is used as the peak stability characterizing the worst fluctuation situation under that amplitude step, that is, the stability under the most severe fluctuation conditions. The upper quartile can be calculated from the set of sorted standard deviations. When the amount of data is small, it can also be calculated by interpolation.

[0054] The baseline stability and peak stability are weighted and summed according to preset weights. The result is used as the amplitude stability index or phase stability index. The weighted summation assigns different weights to the baseline stability and peak stability according to different needs or standards, so as to more accurately reflect the stability of the headphones.

[0055] This embodiment calculates the median and upper quartile of the standard deviation set of amplitude sub-segments or the standard deviation set of phase sub-segments, and then performs a weighted summation based on preset weights to generate amplitude stability and phase stability indices, effectively improving the accuracy and comprehensiveness of headphone quality assessment.

[0056] Based on the above embodiments, step S50, determining the headphone quality according to a pattern, includes: With frequency as the horizontal axis and standard electrical signal amplitude as the vertical axis, denoted as the frequency amplitude plane, the amplitude stability index and phase stability index corresponding to each coordinate point are mapped into a two-dimensional stability vector, which contains amplitude and phase stability data and can comprehensively reflect the performance of the headphones under the specified frequency and amplitude conditions. The construction of the frequency amplitude plane can be automatically controlled by the signal generation and data acquisition system. The data of each frequency point and amplitude step are collected through testing and vector mapping to ensure the integrity and accuracy of the stability index.

[0057] On the frequency amplitude plane, surface fitting is performed on all two-dimensional stability vectors to obtain amplitude stability trend surfaces and phase stability trend surfaces, revealing the variation law of headphone performance under different conditions. Surface fitting can use polynomial fitting, spline interpolation or other efficient fitting algorithms. The appropriate method can be selected according to the distribution of data, which can accurately describe the stability changes of the headphone at various frequencies and amplitudes.

[0058] Calculate the gradient fields of the amplitude stability trend surface and the phase stability trend surface. The gradient field can be calculated using numerical differentiation methods (such as the central difference method). Analyze the speed and direction of stability change at each frequency point. The gradient field represents the direction and rate of stability change, which can help identify the stability changes of the headphones at different frequencies and amplitudes. A larger gradient value indicates that the performance of the headphones fluctuates greatly at that frequency and amplitude, and there may be distortion or instability.

[0059] The region in the gradient field whose modulus value is greater than a preset sensitivity threshold is identified and defined as the performance vulnerability region. The location and range of the performance vulnerability region on the frequency amplitude plane are recorded. The performance vulnerability region refers to the region in which the headphones exhibit large fluctuations or instability under specific frequency and amplitude conditions, which helps to provide a basis for headphone performance optimization. The set sensitivity threshold can be adjusted according to the headphone performance standards and testing requirements to help identify those frequency bands that are prone to causing sound quality problems or distortion, and ensure that the headphone design can meet strict sound quality requirements.

[0060] Based on location and range, the proportion of the total area of ​​all performance-vulnerable regions to the frequency amplitude plane and the average gradient magnitude within the performance-vulnerable regions are calculated and recorded as a rule. The proportion of the total area reflects the stability fluctuation of the headphones throughout the entire test frequency band, while the average gradient magnitude can help determine the severity of performance in these fluctuating regions. The area calculation can be achieved through integration methods to calculate the proportion of all vulnerable regions in the frequency amplitude plane, ensuring that the evaluation results are comprehensive and representative. The average gradient magnitude can provide an overall stability index for further determining the quality of the headphones.

[0061] To determine headphone quality, if the total area of ​​the performance vulnerability zone is too large or the gradient modulus is high, it indicates that the headphone is less stable at certain frequencies and amplitudes, which may affect sound quality and thus determine that the headphone is unqualified. Conversely, if the vulnerability zone is small and the gradient modulus is low, it indicates that the headphone's performance is relatively stable and meets the quality standards. Quality judgment can combine multiple standards, such as the allowable proportion of vulnerability zone area and gradient modulus, to comprehensively evaluate the overall performance of the headphone.

[0062] The present invention also provides an earphone quality testing system, comprising: Check the calibration module, check the integrity of the headphone assembly and send it to the testing area, calibrate the reference microphone; The signal driving module applies a predetermined standard electrical signal to the earphone core under test in the earphone, driving the earphone core under test to generate a corresponding first acoustic signal in the free field or coupling cavity. The coupling conversion module acoustically couples the reference microphone to the earphone core under test. Driven by a standard electrical signal, the reference microphone acquires a second acoustic signal corresponding to the first acoustic signal and converts the second acoustic signal into a first electrical response signal. The earphone core under test is used as a sound source and acoustically coupled to the earphone's built-in microphone under test. The microphone under test acquires the first acoustic signal and converts the first acoustic signal into a second electrical response signal. An evaluation module is constructed, which uses the first electrical response signal as the acoustic output data and the second electrical response signal as the acoustic input data to build an acoustic-electric closed loop. The quality of the headphones is evaluated based on the acoustic-electric closed loop, and the quality test results are obtained.

[0063] The detection system described above in this invention can effectively realize the headphone quality detection method, and the technical effects it can achieve are as described in the above embodiments, and will not be repeated here.

[0064] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A method for testing the quality of headphones, characterized in that, Includes the following steps: S10: Check the integrity of the headphone assembly and send it to the testing area to calibrate the reference microphone; S20: Apply a predetermined standard electrical signal to the earphone core under test in the earphone, and drive the earphone core under test to generate a corresponding first acoustic signal in the free field or coupling cavity; S30: The reference microphone is acoustically coupled to the earphone core under test. Under the drive of the standard electrical signal, the reference microphone acquires a second acoustic signal corresponding to the first acoustic signal and converts the second acoustic signal into a first electrical response signal. S40: Using the earphone chip under test as a sound source, acoustically couple it with the microphone under test built into the earphone, collect the first acoustic signal through the microphone under test, and convert the first acoustic signal into a second electrical response signal; S50: Construct an acoustic-electric closed loop using the first electrical response signal as acoustic output data and the second electrical response signal as acoustic input data, evaluate the quality of the headphones based on the acoustic-electric closed loop, and obtain the quality test results.

2. The headphone quality testing method according to claim 1, characterized in that, In step S20, driving the earphone chip under test to generate a corresponding first acoustic signal in a free field or coupling cavity includes: A standard electrical signal of predetermined frequency and amplitude is applied to the earphone core under test, and the amplitude and frequency of the standard electrical signal are adjusted to control the diaphragm vibration of the earphone core under test, thereby generating a corresponding acoustic signal. In a free field, the first acoustic signal of the earphone core under test is generated by propagating through the air based on the acoustic signal; In the coupling cavity, the acoustic signal generated by the earphone chip under test is guided to the cavity of the coupling cavity to generate the first acoustic signal.

3. The headphone quality testing method according to claim 1, characterized in that, In step S30, the reference microphone is acoustically coupled to the earphone core under test, including: The reference microphone is placed on the acoustic output path of the earphone core under test, with the receiving end of the reference microphone facing the diaphragm or sound wave output end of the earphone core under test, thus forming effective acoustic coupling.

4. The headphone quality testing method according to claim 1, characterized in that, In step S30, the second acoustic signal is converted into a first electrical response signal, including: Set the filtering parameters and perform frequency-selective filtering on the acquired second acoustic signal to preserve the audio range required for headphone testing; Set the gain parameter, adjust the gain of the filtered second acoustic signal, and convert the gain-adjusted second acoustic signal into an electrical signal; The electrical signal is subjected to time-frequency analysis to extract its frequency, amplitude, and phase information, and the data is processed to generate electrical signal data suitable for quality assessment. The electrical signal data is compared with a preset standard signal, and the gain parameter and the filtering parameter are adjusted in real time to generate the first electrical response signal.

5. The headphone quality testing method according to claim 3, characterized in that, In step S50, the acoustic-electric closed loop is constructed, including: Multiple frequency points are preset, and the amplitude and phase values ​​of the acoustic output data and the acoustic input data are simultaneously collected at the preset frequency points; Calculate the amplitude difference and phase difference between the acoustic output data and the acoustic input data at each frequency point; The amplitude difference is compared with a preset amplitude tolerance range, and the phase difference is compared with a preset phase tolerance range. When the amplitude difference at any of the frequency points exceeds the amplitude tolerance range or the phase difference exceeds the phase tolerance range, a parameter adjustment command is generated; Adjust the first electrical response signal or the second electrical response signal according to the parameter adjustment command to form an acoustic-electric closed loop.

6. The headphone quality testing method according to claim 5, characterized in that, In step S50, the headphone quality is evaluated based on the acoustic-electric closed-loop method, including: The standard electrical signal is controlled to increase its amplitude in a stepwise manner at multiple frequency points, forming an amplitude step; At each amplitude step of each frequency point, the instantaneous amplitude fluctuation value and instantaneous phase jitter value of the second electrical response signal relative to the first electrical response signal are monitored and recorded; A time-domain stability analysis is performed on the instantaneous amplitude fluctuation value and the instantaneous phase jitter value, and their standard deviations on each amplitude step are calculated to obtain the amplitude stability index and the phase stability index, respectively. Analyze the variation patterns of the amplitude stability index and the phase stability index with frequency and amplitude, and determine the headphone quality based on these patterns.

7. The headphone quality testing method according to claim 6, characterized in that, In step S50, the amplitude stability index and phase stability index are obtained, including: During the stabilization phase of each amplitude step, the instantaneous amplitude fluctuation value and the instantaneous phase jitter value are continuously collected with a fixed sampling window to form the original data sequence; Outlier detection is performed on each of the original data sequences. Outlier data points caused by external transient interference are identified and removed using the interquartile range method, generating the removed data. Linear interpolation is used to fill the gaps in the removed data, forming a purified amplitude fluctuation sequence and phase jitter sequence; Each amplitude fluctuation sequence is divided into multiple consecutive and partially overlapping amplitude analysis segments, and each phase jitter sequence is divided into multiple consecutive and partially overlapping phase analysis segments. Calculate the standard deviation of each amplitude analysis segment and each phase analysis segment to obtain the standard deviation set of amplitude segments and the standard deviation set of phase segments; Based on the set of standard deviations of the amplitude segments, their statistical characteristic values ​​are calculated to generate an amplitude stability index; based on the set of standard deviations of the phase segments, their statistical characteristic values ​​are calculated to generate a phase stability index.

8. The headphone quality testing method according to claim 7, characterized in that, In step S50, its statistical characteristic values ​​are calculated, including: The median of the standard deviation set of the amplitude sub-segments or the standard deviation set of the phase sub-segments is taken as the benchmark stability characterizing the steady-state fluctuation level under the amplitude step. The upper quartile of the standard deviation set of the amplitude segment or the standard deviation set of the phase segment is taken as the peak stability characterizing the worst fluctuation case under the amplitude step. The baseline stability and the peak stability are weighted and summed according to a preset weight, and the result is used as the amplitude stability index or the phase stability index.

9. The headphone quality testing method according to claim 6, characterized in that, In step S50, determining the quality of the headphones according to the aforementioned rule includes: With frequency as the horizontal axis and standard electrical signal amplitude as the vertical axis, the frequency amplitude plane is denoted as the frequency amplitude plane. The amplitude stability index and the phase stability index corresponding to each coordinate point are mapped into a two-dimensional stability vector. On the frequency amplitude plane, surface fitting is performed on all the two-dimensional stability vectors to obtain amplitude stability trend surface and phase stability trend surface, respectively; Calculate the gradient field of the amplitude stability trend surface and the gradient field of the phase stability trend surface; Identify regions in the gradient field whose modulus is greater than a preset sensitivity threshold, define them as performance-vulnerable regions, and record the location and range of the performance-vulnerable regions on the frequency amplitude plane; Based on the location and range, calculate the ratio of the total area of ​​all the performance-vulnerable regions to the frequency amplitude plane and the average value of the gradient magnitude within the performance-vulnerable regions, and record it as the rule; The quality of the headphones is determined based on the aforementioned rules.

10. A headphone quality testing system, using the headphone quality testing method as described in any one of claims 1 to 9, characterized in that, include: Check the calibration module, check the integrity of the headphone assembly and send it to the testing area, calibrate the reference microphone; The signal driving module applies a predetermined standard electrical signal to the earphone core under test in the earphone, driving the earphone core under test to generate a corresponding first acoustic signal in a free field or coupling cavity. The coupling conversion module acoustically couples the reference microphone to the earphone core under test. Driven by the standard electrical signal, the reference microphone acquires a second acoustic signal corresponding to the first acoustic signal and converts the second acoustic signal into a first electrical response signal. The earphone core under test is used as a sound source and acoustically coupled to the earphone's built-in microphone under test. The microphone under test acquires the first acoustic signal and converts the first acoustic signal into a second electrical response signal. An evaluation module is constructed, which uses the first electrical response signal as acoustic output data and the second electrical response signal as acoustic input data to build an acoustic-electric closed loop. The quality of the headphones is evaluated based on the acoustic-electric closed loop to obtain quality test results.

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