橢圓揚聲器的製造與應用研究

Abstract

中文摘要 本文主要探討電磁動圈式平面橢圓形激震器的製造與應用研究。 傳統圓形平面激震器受限於空間大小，無法使用較大之磁體以增加磁通密度(B)大小與增加揚聲器之出力，進而提昇聲壓整體感度。橢圓形揚聲器可改善上述之問題，且對於細長形振動板之變形有助於改善第一彎曲模態之發生，也就是中音谷的問題，中音谷的發生與振動板的長、寬比與橢圓形音圈的長軸、短軸比有明顯關係，找出其關係式並藉由實際製作三組不同尺寸大小之揚聲器，驗證理論分析之準確性與實用性。 本文中將討論如何製作出橢圓形揚聲器之各部位零件與組裝，但橢圓形音圈較圓形音圈不易定位且易有摩擦問題，將研究與設計適合於平面橢圓形揚聲器使用之平面條狀彈波。在理論分析上，利用有限元素軟體ANSYS建構不同設計的平面條狀彈波分析模型，將由實驗測得參數，與分析運算所得到之結果作為驗證與比較後，在進行不同設計之平面條狀彈波之聲壓曲線量測與分析，藉此改善摩擦問題，最後使用分析之方式，以達到節省實驗次數與簡化設計流程之目的，可得到一激震器搭配平面條狀彈波的較佳設計。

ABSTRACT This paper is focused on the manufacture and application of an elliptic electrodynamic exciter. Traditional flat loudspeaker is limited by the space so that we can not use the bigger electrodynamic exciters to improve the flux density and force, then to improve the SPL(Sound Pressure Level). But the above problem can be overcome if an elliptic exciter is used because we can increase the magnetic size. When we use it on a flat loudspeaker, it also can improve the SPL drop induced by the first bending mode of the radiating plate effectively. Then putting into practice, we compare and discuss the differences between the results of experiment and simulation. The electrodynamic exciter using flat damper can improve the low frequency response of the flat speaker. When designing a thin and long flat loudspeaker, we may suffer the loss of bass sound for the speaker, due to the increase in stiffness of the conventional corrugated circular damper. To overcome this difficulty, in this paper a flat strip-type damper is developed. We will study the shape, materials and suspension of the strip-type damper. The finite element method is used to investigate the deformation and flexibility of the damper. To verify the feasibility of the design of the damper, a flat speaker is fabricated and tested. The experimental results have shown that the strip-type can work properly and provide sufficient flexibility to the flat speaker.