主动降噪耳机的降噪性能测量方法研究

    Investigating Measurement Techniques for Assessing Noise Reduction in Active Noise-Cancelling Earphones

    • 摘要: 研究主动降噪耳机性能测试的实验条件和参数设置,对于行业标准的制定,以及相关企业进行产品的测试,具有重要的意义。针对噪声源的布放方式和数量选取对耳机降噪性能测试的影响,选取了三种有源降噪耳机,在消声室环境下,选用不同数量的声源布放于不同的方位角,对比测试了耳机的主动降噪量,分析了在不同噪声源条件下的主动降噪性能。实验结果表明,在耳机的主要工作频带内,将单个声源布放于不同角度下多次测量结果平均,可以代替使用八个声源进行测试的结果。使用四个声源在相应角度下两次测量结果的平均,与欧洲电信标准协会现行标准的八声源测试方法所得到的结果非常接近。因此,在耳机的主动降噪性能测试中,可以用单个声源在多个角度布放,分别测量降噪性能,用测量结果的平均值代替八个声源同时发声时的测量结果。更精确的测量方法是使用四个声源放置在相应的角度下进行两次测试并对结果进行平均。两种测试方法在简化测量系统的同时,保证了测量结果的可靠性。

       

      Abstract: Investigating the appropriate experimental conditions and parameter settings for evaluating active noise-cancelling earphones’ performance is crucial for developing industry standards and conducting enterprise product tests. This study utilizes three types of active noise-cancelling earphones to explore the effects of sound source layout and quantity on noise reduction measurements. In an anechoic chamber, various numbers of sound sources are positioned at different azimuthal angles to measure earphones’ noise reduction capabilities. The study analyzes the earphones’ active noise reduction performance under varying sound source conditions. Results indicate that in the earphones’ primary operational frequency band, using a single sound source placed at different angles and averaging these measurements can substitute for testing with eight simultaneous sources. The mean of two measurements with four sources at corresponding angles closely aligns with the European Telecommunications Standards Institute’s current eight-source testing standard. Thus, for active noise reduction assessment, using a single sound source at multiple angles for separate noise reduction measurements, and averaging these results, can effectively replace the need for eight simultaneous sources. A more precise approach involves two measurements with four sources at designated angles, with the results averaged. These methodologies simplify the testing apparatus while ensuring measurement reliability.

       

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