动圈扬声器涡流阻抗建模

由音圈涡流效应引起的涡流阻抗对小信号下动圈扬声器的高频响应影响较大。基于集总参数系统等效电路法,将涡流阻抗的幅值和相位分别表示为角频率的幂指数函数,提出了音圈涡流阻抗的幂指模型。使用激光阻抗测量系统,测量得到了3种类型6只扬声器单元的电阻抗曲线,并采用最小二乘法对实测阻抗进行曲线拟合,得到了涡流阻抗的模型参数。分析了模拟阻抗值与实测值的误差,结果表明:幂指模型的模拟结果准确反映了实测涡流阻抗随频率的变化规律,幅值和相位误差均较小,与实验吻合较好。

Modeling of eddy current impedance in moving-coil loudspeakers

he eddy current impedance in voice coil affects the behaviors of moving-coil loudspeakers under small input voltage in high frequency range. Based on equivalent electrical circuit method, using the power function to fit the measured magnitude and phase of the eddy current impedance, the power function model was presented. Six loudspeaker units in types of woofers, midranges and tweeters were tested by laser tested systems, and the model parameters were identified by fitting the measured impedance curve with the method of Least- Mean-Squares (LMS). By comparing the differences of the predict values by models with the measured data, the accuracy were investigated. The results find that, the power function model can effectively give the right tendency of measured eddy current impedance magnitude and phase varying with frequencies, and behaves good correspondences with the measured data.