Diffraction effects on the measurement of total harmonic distortion of microspeakers
This paper aims to eliminate the effects of diffraction on the measurement of total harmonic distor-tion(THD)of microspeakers and studies the diffraction effects on the measurement of THD of microspeakers based on the extended Biot-Tolstoy-Medwin model,two different cases with and without the consideration of the backward diffractions were investigated,which correspond to different practical conditions of microspeaker drivers and closed-box microspeaker modules.This article uses barrier to test due to its simplicity and stabilization.Because diffraction is related to the size of baffle and the installation position of microspeakers,this article installs microspeaker in a fixed position on a fixed size baffle.This article theoretically calculates the diffraction curves of baffle at different measuring distances,analyzes the impact of diffraction on the THD of microspeakers under corresponding conditions,and conducts experimental verification.The experimental re-sults are in good agreement with theoretical calculations,demonstrating the accuracy of the calculation method in this paper.This study shows that the diffraction effects on the measurement of THD of microspeakers is greatly affected by baffle.The farther the test distance,the greater the impact.The diffraction effect is more obvious when the rear cavity of the microspeaker is open than closed.By using the method presented in this article to calculate the diffraction curve,the THD of microspeakers measured on baffle can be corrected to eliminate the effects of diffraction.
万方数据
维普
