基于等效声容的高频调容腔体设计与仿真

Design and Simulation of High-frequency Dynamic Cavity Based on Equivalent Capacity

针对目前入耳式耳机高频调节困难的问题,提出了一种基于等效声容原理的高频调容动圈式腔体结构设计,并进行了理论分析与仿真设计。分析了耳机各声学元件对频响曲线的影响,通过"等效容性"改变该腔体结构使得在较宽的高频范围内具有好的频响。采用声学有限元法,根据变分原理对声-结构界面阻抗非均匀分布的腔体声场特性进行仿真。仿真的声压云图和频响图说明容值的改变对高频调节的显著作用,且该腔体结构在1 k Hz开始,随腔体范围变化,频率调整范围可达10 d B。同时,为防止耳机内调容运动机构由于应力集中造成的损害和保证耳机实效性,对活动结构进行了运动过程的受力仿真。

A high-frequency dynamic regulation cavity based on equivalent capacity is designed with theoretical analysis and simulation experiments to solve the problem of earphone frequency adjustment difficulties. It is concluded that equivalent capacity has a better frequency response over a wide frequency range by analyzing the main factors related to earphone fre- quency response curve. Cavity acoustic characteristics simulation of acoustic-structural interface impedance in non-unifbrm distribution is obtained by using acoustics finite element analysis method according to variation principle. Acoustic pressure picture and frequency response curve indicate that the change of capacitance could affect hlgh-frequency adjustment; with the change of capacitance, earphone frequency adjustment range can be up to 10 dB. Simultaneously, key moving components are analyzed by force simulation of movement process in case of stress concentration.