Research Center for Testing Technology and Standards, National Research and Innovation Agency Republic of Indonesia (BRIN), Gedung 417, Jalan Kawasan Puspiptek, Muncul, Kec. Setu, Kota Tangerang Selatan, Banten 15314, Indonesia.
NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan.
J Acoust Soc Am. 2023 Feb;153(2):1138. doi: 10.1121/10.0017246.
This article presents a method for determining the acoustic center of a microphone from a sound field measured by optical interferometry. The acoustic center defines the equivalent point source position of a microphone serving as a sound source where the spherical waveform starts to diverge. The value is used to determine the effective distance between microphones for free-field reciprocity calibration. Conventionally, it is determined from the inverse distance law properties of a point source using the transfer function method. In this study, the acoustic center was determined from the projection of the sound field of the microphone. Parallel phase-shifting interferometry was used to measure the line integration of the sound pressure from a microphone. The acoustic center is determined as the position where the squared error between the measured data and the projection model of a point source is minimized. Experiments with the B&K 4180 (Brüel & Kjær, Nærum, Denmark) microphone were performed for frequencies from 10 to 50 kHz. The best acoustic center estimation was obtained at a microphone distance of 0 mm, with a difference of 0.17 mm to the IEC 61094-3 value and 0.36 mm to the Barrera-Figueroa et al. [J. Acoust. Soc. Am. 120(5), 2668-2675 (2006)] result at a measurement frequency of 20 kHz.
本文提出了一种利用光学干涉法测量声场来确定麦克风声心的方法。声心定义了作为声源的麦克风的等效点源位置，球面波从此处开始发散。该值用于确定自由场互易校准中麦克风之间的有效距离。传统上，它是根据点源的反距离定律性质，使用传递函数法来确定的。在本研究中，声心是从麦克风声场的投影来确定的。平行相移干涉法用于测量麦克风声压的线积分。声心是通过最小化测量数据与点源投影模型之间的平方误差来确定的。在 10 至 50 kHz 的频率范围内，对 B&K 4180（丹麦布鲁尔和凯尔，纳鲁姆）麦克风进行了实验。在麦克风距离为 0 毫米时，获得了最佳的声心估计，与 IEC 61094-3 值相差 0.17 毫米，与 Barrera-Figueroa 等人在 20 kHz 测量频率时的结果相差 0.36 毫米。
