長形高功率平面揚聲器之研製

Abstract

本文研究長形高功率揚聲器之設計與實作，首先為揚聲器彈性支承的研製，其中包括支承材料的選擇、支承結構的幾何形狀。此彈性支承可用以提高揚聲器容許的最大功率，並增加揚聲器的穩定性及回復性，使振動板在大瓦數的工作下能順利回復至平衡位置，同時也解決了僅有傳統彈波及懸邊在長久工作下產生的塌陷問題。另外也使用複合材料來加勁振動板，因為不良模態的存在破壞了揚聲器的聲射，以致在某些頻段下，聲壓的輸出產生落差。本文應用驗證過的ANSYS有限元素模型作分析來找出這些不良的模態，由碳纖三明治板的減重著手，找出適合抑制或導正這些不良模態的加勁區域，平滑揚聲器的聲壓曲線並提高其感度。最後本文依分析的結果實際製作出揚聲器並量測其聲壓曲線，結果顯示其確有較平滑的聲壓曲線及較高感度的表現。

There are two major parts in the thesis. The first part is related to the design and manufacture of the elastic suspensions of loudspeakers, including the choices of the materials of the supports and their geometrical shapes, which are used to increase the stability and recoverability of loudspeakers. This kind of design makes the panel resume to its equilibrium position under large power easily. It also raises the maximum allowable output power and improves the bass performance while at the same time, the collapse problem of conventional suspension under long period working is also solved. The second part is related to the design of reinforced panel using composite materials. Some mode shapes that may have adverse influences on the sound radiation in certain frequency ranges are determined using a verified ANSYS FEA model. An appropriate reinforced region is determined to suppress the detrimental modes while at the same time, reduce panel weight, make the SPL curve smoother and the speaker possess higher sensitivity.