臺灣博碩士論文加值系統

當3C產品體積越來越小，釵h弁鄐w無法滿足使用者的需求，因此產生了很多周邊產品，若含有音箱，最困難的就是低頻重放問題。低聲頻的重放受揚聲器音箱所左右，揚聲器音箱有釵h種型式用以重放不同特徵的聲音，如何以有效降低低頻臨界將是個值得探討的課題。

本論文以一市售消費性電子周邊商品為導向的可攜式筆電散熱座揚聲器做研究，量測時發現中頻部分有一波谷，進而探討為何造成此波谷及此波谷對人們聽覺的影響；文中提出一解析方法針對揚聲器單體、封閉式揚聲器音箱、開口式揚聲器音箱做模擬，且與實驗做驗證，並探討導音管長度、導音管管徑、音箱容積大小與可攜式筆電散熱座揚聲器一些零件設計對頻率響應的影響，這些分析結果將可以當成設計音箱的依據。

Research efforts nowadays devote to developing small, slim, and multi-functional 3C products to capture market share. The loudspeakers in such products are required to integrate multiple functions into a small volume and also to be capable of playing euphonious music. The low-frequency extension is then mainly desired for 3C’s loudspeakers. As a result, how to obtain the lower frequency response of a loudspeaker is a crucial issue. This thesis aims at analyzing the sound pressure response of a portable loudspeaker which is a companion of laptop computers. From the soulnd pressure level curve (SPL) of the loudspeaker, there exists a dip in middle frequency range. To realize the cause of the dip and to see how it affects human hearing, the thesis proposes an electro-mechano-acoustical analogous model to simulate the SPL of the loudspeaker. The model is further extended to analyze closed-box and vented-box loudspeaker systems. Also, experiments are conducted for verifications. The simulation predictions show fairly good agreement with the experimental results. Finally, the thesis investigates the effect of waveguide length and diameter and the volume of the box on the frequence response. Analysis results would assist in knowledge improvement and understanding of portable loudspeakers which may guide to better design with further improved in portable loudspeakers.

誌謝 i
摘要 ii
Abstract iii
目錄 v
圖目錄 viii
表目錄 xi
第一章 緒論 1
1-1 前言 1
1-2 研究動機 2
1-3 文獻回顧 3
1-4 論文架構 5
第二章 應用原理 7
2-1 電路類比 7
2-2 力學元件類比電路 8
2-3 聲學元件類比電路 9
2-4 轉換機制 11
2-5 聲學輻射阻抗 13
2-6 管之聲學阻抗 15
第三章 揚聲器系統模擬與分析 Case1 27
3-1 音箱介紹 27
3-2 實驗量測與量測結果 28
3-2.1 SoundCheck軟體量測步驟與結果 28
3-2.2 KLIPPEL量測系統 29
3-3 量測與模擬結果 30
3-3.1 揚聲器單體之量測結果與模擬比較 30
3-3.2 封閉式揚聲器音箱之量測結果與模擬比較 32
3-3.3開口式揚聲器音箱之量測結果與模擬比較 33
3-3.4結論與討論 35
第四章 中音波谷改良 48
4-1 前空腔效應 48
4-2 改善前空腔效應 Case1 49
4-2.1 實驗改善與模擬比較 49
4-2.2 不同參數對頻率響應之影響 51
4-3 揚聲器系統模擬與分析 Case2 53
4-3.1 裝置介紹與實驗量測 53
4-3.2 量測與模擬結果比較 55
第五章 結論與未來展望 68
5-1 結論 68
5-2 未來展望 70
參考文獻 71

[1]L. L. Beranek, “Acoustic,” McGraw-Hill, 1954 and Acoustical Society of America, 1986.
[2]A. N. Thiele, “Loudspeakers in Vented Boxes, Parts I and II,” Proceedings of the IRE, Australia, vol. 22, pp. 487-508, 1961.
[3]R. H. Small, “Closed-Box Loudspeaker Systems, Parts I and II,” J Audio Eng. Soc., vol. 20, no. 10, pp. 798-808, Dec. 1972; vol. 21, no. 1, pp. 11-18, Jan./Feb. 1973.
[4]R. H. Small, “Closed-Box Loudspeaker Systems, Parts I and II,” J Audio Eng. Soc., vol. 20, no. 10, pp. 798-808, Dec. 1972; vol. 21, no. 1, pp. 11-18, Jan./Feb. 1973.
[5]H. F. Olson, “Acoustical Engineering,” Professional Audio Journals Inc., Philadelphia, 1991.
[6]Richard H. Lyon, “On the Low-Frequency Radiation Load of a Bass-Reflex Speaker,” The Journal of the Acoustical Society of America, vol. 29, issue 5, pp. 654, 1957.
[7]R.L. Pritchard, “Mutual Acoustic Impedance between Radiators in an Infinite Rigid Plane,” Journal of the Acoustical Society of America, Volume 32, Issue 6, 1960.
[8]Macey, “Acoustic and Structure Interaction Problems using Finite and Boundary Elements,” PhD thesis, University of Nottingham, November, 1987.
[9]Kaizer, Arie J. M.;Leeuwestein, Ad, “Calculation of the sound radiation of a non-rigid loudspeaker diaphragm using the finite element method,” J Audio Eng. Soc., Vol. 36, no. 7/8, pp. 539-551, July 1988.
[10]W. Klippel, U. Seidel, “Fast and Accurate Measurement of Linear Transducer Parameters,” Presented at the 110th Convention of the Audio Enineering Society, Amsterdam, 2001.
[11]王以真，“ 實用揚聲器技術手冊 ”，國防工業出版社， 2006年6月。
[12]山本武夫，王以真，吳光威，張紹高，“ 揚聲器系統 ”，國防工業出版社， 2010年1月。
[13]杜扑堙A朱哲民， 龔秀芬，“ 聲學基礎 ”，南京大學出版社， 2001年3月。
[14]白明憲，“ 工程聲學 ”，全華科技圖書股份有限公司出版， 2008年9月。
[15]郭晟宇，“ 可攜式揚聲器之分析與模擬 ”，私立逢甲大學機械工程研究所碩士論文， 2007年7月。
[16]洪梓濬，“ 內耳式耳機及塞耳式耳機結合人工耳之頻率響應分析 ”，私立逢甲大學機械工程研究所碩士論文， 2010年6月。
[17]王以真，沈佛星，“ 音箱探討(一)(二)(三) ”，電聲技術， 2006年第十一期。
[18]David Weems, “Designing, Building, and Testing Your Own Speaker System with Projects,” McGraw-Hill, 1996.
[19]G. H. Yoon, Jakob Sondergaard Jensen, Ole Sigmund, “Topology Optimization of Acoustic-Structure Interaction Problems using a Mixed Finite Element Formulation,” International Journal For Numerical Methods in Engineering, vol. 70, issue. 9, pp. 1049-1075, 2007.
[20]Frankort, F. J. M., “Vibration Patterns and Radiation Behavior of Loudspeaker Cones,” J Audio Eng. Soc., vol. 26, issue 9, pp. 609-622, 1978.
[21]Frank Ihlenburg, “Finite Element Analysis of Acoustic Scattering (Applied Mathematical Sciences),” Springer, 1998.
[22]Andrzej Dobrucki, Piotr Pruchnici, Bronislaw Żoltogorski, “Computer modeling of loudspeaker vibrating system”, presented at the 100th Convention of the Audio Eng. Soc., May 1996
[23]Guillaume Pellerin, Jean-Dominique Polack, Jean-Pierre Morkerken, “Finite element methods and equivalent electrical models for loudspeaker characterization”, 2003.
[24]Sakai Shinichi, Kagawa Yukio, Yamabuchi Tatsuo, “Acoustic Field Analysis of a Loudspeaker Enclosure Using the Finite Element Method,” J Audio Eng. Soc., 1982.