揚聲器各元件對聲壓曲線之影響

Abstract

本文主要研究非等向性平板揚聲器，探討揚聲器組成之元件對聲壓曲線的影響。對平面揚聲器來說，聲壓曲線在中音域容易產生明顯的聲壓感度落差，稱為中音谷，中音谷的產生對揚聲器整體感度有不良影響。因此本文透過有限元素軟體ANSYS模擬，以調整各元件參數的方式，尋求消除中音谷的方法，達到聲壓曲線平滑化。本研究先以實驗方式量測平面揚聲器之聲壓曲線，以驗證ANSYS有限元素模型之正確性，利用此模型依序對振動板材料、振動板長寬比、音圈直徑、振動板疊層、懸邊性質等進行分析，找出各元件參數對中音谷的影響。最後以實例證明本文探討之元件參數，對聲壓曲線平滑化之可行性。

In this thesis, the effects of several system parameters on the sound pressure level (SPL) curves of panel-speakers made of different materials are studied via both theoretical and experimental approaches. For the panel-speakers, it is not uncommon to have SPL drops termed as sound valleys on the SPL curves, which can affect the sound quality of the speakers. This research offers a way to eliminate the sound valleys by adjusting the system parameters using the finite element model established on the basis of the simulation software “ANSYS”. In the first place, the experimental results are used to prove the correctness of the ANSYS model which can be used for the following investigation. Then we make changes in the system parameters such as plate material, diameter of coil, lamination arrangement of plate, and properties of elastic support to study the effects of the parameters on the SPL curves of the speakers. Finally, the appropriate system parameters are used to fabricate a panel-speaker to demonstrate the practicability of the design.