虚拟声场用于测量智能音频设备采集指向性的可行性探究

    Exploring Virtual Sound Fields for Directivity Measurement of Smart Audio Devices

    • 摘要: 为更好地满足智能音频设备声音采集指向性的测量需求,提高测量装置的灵活性和效率并降低测量装置的硬件成本,探究了利用虚拟声场来测量智能音频设备声音采集指向性的可行性。虚拟声场采用矢量合成的方法合成。通过声场仿真实验对比了虚拟声源和真实物理声源在声场辐射指向性方面的差异。通过实际测量实验对比了一款声像仪在采集定位虚拟声源和真实物理声源时的指向性差异。声场仿真数据结果表明,双扬声器夹角越小,虚拟声源越容易形成与真实物理声源逼近的声场辐射指向性。频率越低,虚拟声场与真实物理声场辐射指向性逼近的甜点区范围越大。实际测量实验结果表明,频率越低,声像仪采集虚拟声场指向性性能逼近采集物理声场指向性性能。双扬声器夹角在22.5°时,声源频率低于2 kHz时,声像仪采集虚拟声场的方位角精度小于3°;声源频率高于4 kHz时,声像仪难以精准采集虚拟声场的声像方位。虚拟声场可在中低频范围内满足音频设备声音采集指向性的测量要求,可用于灵活地设置复杂虚拟声环境来测量智能音频设备声音采集指向性。

       

      Abstract: To better satisfy the measurement needs for sound acquisition directionality in smart audio devices and to enhance the flexibility, efficiency, and cost-effectiveness of measurement setups, this study explores the viability of using virtual sound fields. Virtual sound fields are synthesized via vector synthesis. The study compares virtual and physical sound sources in terms of sound field radiation directivity through sound field simulation experiments. Furthermore, an acoustic camera is used to compare the differences in directivity when capturing and localizing virtual versus real sound sources. The simulation data reveal that smaller loudspeaker angles make it easier for virtual sources to replicate the sound field radiation directivity of real physical sources. Lower frequencies increase the 'sweet spot' range, where the virtual sound field closely approximates the directivity of the real physical sound field. Practical measurement experiments demonstrate that lower frequencies in the virtual sound field align closer to the physical sound field's directivity. Specifically, with a speaker angle of 22.5° and frequencies below 2 kHz, the acoustic camera achieves azimuthal accuracy of less than 3° for virtual sound fields; however, at frequencies above 4 kHz, the camera struggles to accurately capture the azimuth of virtual sound fields. The virtual sound field proves effective for measuring directionality in mid to low-frequency ranges, offering a flexible approach to creating complex virtual acoustic environments for assessing smart audio devices.

       

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