微型揚聲器於定電壓之動態特性研究

The Research of Dynamic Characteristics of Micro-Speaker at the Constant Voltage

劉興華(Shin-Hwa Liu) ； 劉峰銘(Feng-Ming Liu)

《中華民國振動與噪音工程學會論文集》 2013 (2013/06) Pp. 107-114

摘要

微型揚聲器之交流阻抗常會因為測試方法的不同，得到不同的阻抗特性曲線，影響T&S參數的計算，使頻率響應曲線的模擬出現了變化。定電流與定電壓的試驗選擇，是目前常用的測試技術之一，但也使喇叭的阻抗測試上充滿了許多變數。微型揚聲器於實際電路應用上是使用一定的功率驅動，使其動作上達到特定的能力。測試電壓的不同，亦使揚聲器的阻抗產生不同的變化，致其產生線性與非線性的特性。本文的重點即為探討喇叭阻抗特性於不同量測方法之分析及利用不同電壓測試其阻抗與頻率－聲壓線性能力。然而不同電壓所算取出的T-S參數，用電－機－聲類比電路，模擬頻率－聲壓特性曲線與實測驗證比對，並以振膜之模態分析找出問題發生的可能性。

關鍵字

微型喇叭 ； 線性分析 ； 模態分析

並列摘要

Impedance curves of a micro-speaker are not the same for different test methods. It influences the calculation of T-S parameters which are used to simulate the frequency response curve of a micro-speaker. Constant current testing and constant voltage testing are two common test methods for AC impedance measurement. Actually, the micro-loudspeaker in the circuit is driven by required power which let micro-speaker to achieve the specific capability. But different driving voltages cause the impedance of the loudspeaker varied which induces nonlinear characteristics. The purpose of this paper is to investigate impedance properties of a loudspeaker by using different testing methods, and also to study the linear capability of impedance and sound pressure frequency response at different experiment voltages. Measured sound pressure frequency response curves are compared with simulations from equivalent circuit method by using T-S parameters measured at different voltages. The differences between simulation and measured data are interpreted with the modal analysis of diaphragm.

並列關鍵字

micro-speaker ； linearity ； modal analysis