臺灣博碩士論文加值系統

在電聲設計分析中，常以類比電路法做為揚聲器電聲模擬的主要方法。類比電路法主要將揚聲器零件轉換成等效的電子元件，並且依據相對應的關係繪製成電路，再利用電子電路進行等效電路的分析。此分析的結果雖可以將揚聲器與音箱的聲學特性進行模擬，但類比電路法對於產品外型在聲場中所造成的聲音繞射卻無法進行分析。由實際量測結果得知，聲音傳遞過程中的繞射效應確實存在而使得分析的結果有誤差。LEAP Enclosureshop是揚聲器分析工具，雖提供了不同音箱設計的繞射分析，但卻不適用於3C產品複雜的外型上。
為了分析並解決產品外型造成音波繞射的問題，本研究利用CAD建立3D產品模型，將此3D模型匯入LEAP模擬工具。再依據聲學的觀點，將腔體的複雜幾何形狀利用CAD進行體積精確的計算，將結果於LEAP軟體中以相對應的幾何形狀、參數以及分析的條件輸入。最後利用LEAP不同條件的分析方式進行聲場的模擬，並且與實際量測結果做為驗證。此方法最大的優勢在於了解不同產品造型設計上對聲音繞射的影響，提供3C產品聲學設計時的參考價值。

In the electro-acoustic design and analysis, the electro-acoustic simulations by analog circuit method are usually apply on the speaker, the analog circuit is mainly converted the speaker parts into equivalent electronic components, and according to corresponding relationship of parts drawn into this circuit, and then using analog circuit software to analyze. Although analysis results from this method can be simulated the electro-acoustic characteristics of the speaker, but cannot simulate the product shape diffraction effect in the sound field. Also learned from measurement result, the sound diffraction indeed affects the measurement result. The LEAP Enclosureshop speaker analytical tools provided diffraction analysis of different speaker box design, but cannot apply on the 3C product appearance design.
To solve the diffraction problem of 3C products, this research utilized CAD software to create 3D models and import to LEAP software. According acoustics view to separate complex geometry of cavity and volumetric calculation by CAD software, the result will be input into LEAP software to calculate and perform sound simulation in different condition by LEAP. The advantage of this simulation method is to understand the product appearance design on sound diffraction impact, the simulation result also provides to engineer reference data when electroacoustic products design.

摘　要 i
ABSTRACT ii
誌　謝 iv
目　錄 v
表目錄 vii
圖目錄 viii
第一章　緒論 1
1.1 前言 1
1.2 研究目的 2
1.3 文獻回顧 3
1.4 論文大綱 5
第二章　電聲學基本理論 6
2.1 聲學基礎 6
2.2 微型揚聲器的介紹 9
2.3 聲波傳遞方式 11
2.3.1 聲波反射 12
2.3.2 聲波折射 14
2.3.3 聲波干涉 16
2.3.4 聲波繞射 17
2.4 音箱腔體與出音孔 21
2.5 類比電路法 23
第三章　研究方法 29
3.1 模擬分析 30
3.1.1 電腦輔助繪圖軟體建立3D模型 30
3.1.2 LEAP背景與應用範圍 33
3.1.3 微型揚聲器T-S參數 35
3.1.4 筆記型電腦聲學參數 46
3.1.4.1 微型揚聲器T-S參數 48
3.1.4.2 前腔體、後腔體之容積計算 48
3.1.4.3 微型揚聲器安裝位置 55
3.1.4.4 麥克風量測位置設定 57
3.1.4.5 模擬參數條件設定 58
3.2 實驗量測 61
3.2.1 CLIO電聲量測系統 62
3.2.2 研究樣品的拆解 65
3.2.3 微型揚聲器量測治具製作 67
3.2.4 全無迴響室 68
3.2.5 筆記型電腦頻響曲線量測 69
第四章　實驗結果與討論 72
4.1 模擬分析與實驗結果資料驗證 72
4.2 不同繞射階數與解析頻率分析 78
4.2.1 繞射階數分析 78
4.2.2 繞射解析頻率分析 80
4.3 端口與腔體分析選項的影響 81
4.4 分析與實驗結果 87
第五章　結論與未來展望 88
5.1 結論 88
5.2 未來發展 89
參考文獻 91
附 錄 A 95
附 錄 B 99
著作發表 100
作者簡介 101

[1] B. R. Levy & J. B. Keller, "Diffraction by a Smooth Object," Research report No. EM-109, 1957, December.
[2] R. G. Kouyoumjian & P. H. Pathak. "A Uniform Geometrical Theory of Diffraction for an Edge in a Perfectly Conducting Surface," Proc IEEE ( S0018-9219) , 1974, Vol. 62 No. 11 : 1448.
[3] 王楠著，現代一致性幾何繞射理論，西安，西安電子科技大學出版社，2000，第1-3章。
[4] H. F. Olson, Elements of acoustical engineering, First edition, New York, D. Van Nostrand company Inc, 1940, pp. 17-18.
[5] H. F. Olson, "Direct Radiator Loudspeaker Enclosures," An AES paper Presented, 1950. Octorber 27.
[6] H. F. Olson, Elements of acoustical engineering, Second edition, New York, D. Van Nostrand company Inc, 1957, pp. 17~24.
[7] M. Fresse, An experimental study in near field sound diffraction, McGill University, Montreal Canada, 1966.
[8] S. W. Rienstra, "Sound Diffraction at a Trailing Edge," J. Fluid Mech. (1981), vol. 108, pp. 443-460.
[9] R. M. Bews & M. J. Hawksford, "Application of the geometric theory of diffraction (GTD) to diffraction at the edges of loudspeaker baffles," J. Audio Eng. Soc. Vol. 34, No. 10, 1986 October, pp. 1-2.
[10] U. P. Svensson & K. Wendlandt, "The influence of a loudspeaker cabinet’s shape on the radiated power," 1st international anniversary conference, Vilnius, Lithuania, 2000, pp.189-192.
[11] ADAM Veronique, Loudspeaker behavior under incident sound fields, Ph.D. Thesis, University of Lausanne, Suisse, 2002, pp.19-70.
[12] Tore A. Nielson, Loudspeaker crossover networks, The Technical University of Denmark, Denmark, 2005, pp.46-58.
[13] U. P. Svensson & P. T. Calamia, "Edge-diffraction impulse responses near specular-zone and shadow-zone boundaries," AcTA Acoustica united with Acustica scientific papers Vol. 92, ,2006, 501-512
[14] P. T. Calamia & U. P. Svensson, "Fast time-domain edge-diffraction calculations for interactive acoustics simulations," Hindawi, volume 2007, article ID 63560, 2006.
[15] Tore Skogberg, Loudspeaker Cabinet Diffraction, Ph.D. Thesis, University of Denmark, Denmark, 2006, pp56-60.
[16] Lars Enggaard & Lars Juul Mikkelsen, Advnaced loudspeaker modelling and automatic crossover network optimization, Universtity of Aalborg, Aalborg, Denmark, 2007, pp. 36-41 & 77-79
[17] J. I. Fjeldsted, "Diffraction of sound waves by an aperture in an acoustic baffle,"
A Capstone Research Paper submitted to the faculty of Brigham Young University, Provo UT84602, U.S. 2008, pp1-2.
[18] P. T. Calamia, Advances in edge-diffraction modeling for virtual-acoustic simulations, Princeton of University, Princeton NJ08544, U.S. 2009. Ch2.2 & Ch3.
[19] G. D. Durgin, "The practical behavior of various edge-diffraction formulas," IEEEA Antennas and Propagation Magazine, Vol. 51, No.3, June 2009.
[20] Dirk Schroder, U. P. Svensson & Michael Vorlander, "Open measurements of edge diffraction from a noise barrier scale model," Proceedings of the International Symposium on Room Acoustics, Melboume, Australia, 2010.
[21] Masashi Okada, Takao Onoye & Wataru Kobayashi, "A ray tracing simulation of sound diffraction based on analytic secondary source model," 19th European signal processing conference, Barcelona, Spain, 2011.
[22] LE Yi, SHEN Yong & XIA Jie, "Calculation of loudspeaker cabinet diffraction and correction," Labortory of modern acoustics and institute of acoustics, vol. 28, No.10, 2011.
[23] J. Piechowicz, "Sound wave diffraction at the edge of a sound barrier," Department of mechanics and virbroacoustics, AGH university, al. A. Mickiewicza 30, Poland.
[24] Jeremy M. Wolfe & Keith R. Kluender & Dennis M. Levi, Sensation & Perception, Sinauer Associates, Incorporated, 2011, Ch 9.
[25] David Havelock, Sonoko Kuwano & Michael Vorlander, Handbook of Signal Processing in Acoustics volume 1, Springer, USA, 2008.
[26] Course material on Electroacoustic Transducer design, School of C.S.E, University of Salford, Acoustics, Audio and Video Group. P33~34 & P47~53
[27] Alex Salvatti & Doug Button, "Maximizing performance from loudspeaker ports, " Alex Salvatti and Doug Button, JBL Professional, Northridge, California, 2002
[28] T. D. Rossing, Springer handbook of acoustics, New York, Springer Science + Bussiness Media, 2007, Ch3.17 & Ch4.5.
[29] John Borwich, Loudspeaker and Headphone Handbook, Third Edition, London: Focal Press, 2001.
[30] John Eargle, JBL Sound System Design Reference manual, Third Edition, January 1999.
[31] Tom Hsu, Ph.D, Foundations of physics, Second Edition, Cambridge Physics Outlet, 2005, Ch12
[32] Michael Syskind Pedersen, Source Separation for Hearing Aid Applications, Technical University of Denmark , Kongens Lyngby 2006. Ch1.1
[33] 長岡鉄男 著/王明淵譯，圖解揚聲器，台南，正言出版社，1976
[34] 陳文華 編著，實用揚聲器技術，台北，文笙書局，1979
[35] 馬大猷 著，現代聲學理論基礎，北京，科學出版社，2004
[36] 馬大猷 沈豪 著，聲學手冊，北京，科學出版社，2004
[37] 蔡國隆、王光賢、涂聰賢 編著，聲學原理與噪音量測控制，台北市，全華科技圖書館份有限公司，2005
[38] 白明憲 編著，工程聲學，台北縣土城市，全華科技圖書股份有限公司，2008
[39] 杜功煥、朱哲民、龔秀芬 著，聲學基礎，南京市，南京大學出版社，2001