揚聲器振膜動態量測之探討

Study on Vibration Measurements of Loudspeaker Diaphragm

鄭緣堂(Yuan-Tang Cheng)

指導教授 ： 劉興華

國立臺北科技大學/機電學院/車輛工程系所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00047

摘要

近年來,電聲產業的快速發展，從手機到筆電乃至當紅的iPad對於其聲音逐漸重視其音質。而現在揚聲器的訴求不外乎體積更小、更輕、成本更低廉且兼具低失真及發揮最大效率。而量測是診斷一個揚聲器好壞與否的基礎，故本文將著重在量測技術方法上。其主軸圍繞在機械振動量測，對振膜表面的振動運用非接觸式之雷射測振儀量及雷射位移計測出振膜的速度及位移，並藉由活塞於無限大隔板運動理論，將實驗所量測到振膜的振動量轉換為聲壓並與聲學麥克風在全無迴響室所量測到聲壓做比對。探討各量測方法所適用的範圍及優缺點比較，提供揚聲器的性能除麥克風外其他量測方法的可行性。

關鍵字

揚聲器 ； 振膜振動 ； 雷射測振儀

並列摘要

The electro-acoustic industry progress quickly in recent years. People require high sound quality for products such as mobile phones, notebooks, and the i-pad. The loudspeakers demand not only smaller, cheaper but also higher efficiency with lower distortion. This study will focus on measurement techniques because measurement is the basis of diagnosing. In this study, diaphragm vibration is measured by non-contact laser vibrometer and laser displacement sensor. From the theory of sound radiation from piston motion in an infinite baffle, sound pressure can be calculated from measured velocity and displacement data and compared with measured data from microphone in the anechoic chamber. The purpose of this study is to investigate other measurement methods for loudspeaker measurement besides the conventional method with microphone.

並列關鍵字

loudspeaker ； diaphragm vibration ； laser vibrometer

參考文獻

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