Department of Mechanical Engineering, National Taiwan University, Number 41, Section 4, Roosevelt Road, Taipei, 10617, Taiwan.
J Acoust Soc Am. 2019 Oct;146(4):2619. doi: 10.1121/1.5130196.
This study modeled the circular diaphragm of push-pull electrostatic speakers using electro-mechano-acoustical equivalent circuits to determine the frequency responses related to the average displacement and sound pressure of the diaphragm with respect to acoustic impedance effects. A laser vibrometer system was used to measure the displacement in the center of the circular diaphragms (60 mm and 65 mm in diameter) in optically transparent indium tin oxide (ITO) electrostatic speakers. The sound pressure levels (SPLs) were predicted using the average displacement of the diaphragm without resorting to sound field measurements or finite element analysis. The predicted SPL results were then compared to acoustic measurements. The results demonstrate that ITO plates are a practical tool for the measurement of displacement and the prediction of SPLs. When the proposed electrostatic speaker (65-mm-diameter diaphragm) design was applied to the over-ear electrostatic headphone, the SPL curve obtained from artificial ear measurements was similar to the preferred target curve of Harman International (Stamford, CT). This resulted in outstanding sound quality comparable to that of high-end commercial dynamic headphones.
本研究采用机电声等效电路对推挽式静电扬声器的圆形振膜进行建模，以确定与声学阻抗效应相关的平均振膜位移和声压的频率响应。激光测振仪系统用于测量光学透明氧化铟锡（ITO）静电扬声器中圆形振膜（直径为 60mm 和 65mm）中心的位移。使用不依赖声场测量或有限元分析的振膜平均位移来预测声压级（SPL）。然后将预测的 SPL 结果与声学测量结果进行比较。结果表明，ITO 板是测量位移和预测 SPL 的实用工具。当将所提出的静电扬声器（直径 65mm 振膜）设计应用于头戴式静电耳机时，从人工耳测量获得的 SPL 曲线与 Harman International（康涅狄格州斯坦福德）的首选目标曲线相似。这使得音质出色，可与高端商用动圈耳机相媲美。
