虛擬環繞架構於立體聲揚聲系統之設計與實現; Design and Implementation of a Virtual Surround Architecture on Stereo Loudspeaker Systems

NCUIR > College of Electrical Engineering & Computer Science > Executive Master of Communication Engineering > Electronic Thesis & Dissertation > Item 987654321/60946

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/60946

Title:	虛擬環繞架構於立體聲揚聲系統之設計與實現;Design and Implementation of a Virtual Surround Architecture on Stereo Loudspeaker Systems
Authors:	吳耀豐;Wu,Yau-feng
Contributors:	通訊工程學系在職專班
Keywords:	虛擬環繞;立體聲揚聲
Date:	2013-07-25
Issue Date:	2013-08-22 12:07:23 (UTC+8)
Publisher:	國立中央大學
Abstract:	在這個3D虛擬實境多媒體應用普及的時代裡，雖然應用上大多以3D視訊為主，但若加入3D音訊能讓使用者有更豐富的環境體驗感以及更好得聆聽感受。傳統的立體聲系統大多是雙聲道的，只能保持聲音的部分空間分佈特性，為聆聽者提供二維的平面分辨能力，無法再現三維的空間音響效果。儘管多聲道環繞音效的出現有效地解決了這一問題，但是這種系統需要特製的音源，對重放設備和聆聽環境的要求嚴格，使它的應用受到了限制。有鑒於此，人們提出了虛擬環繞音效的理論，並圍繞它進行了多方面的研究。對雙聲道虛擬環繞音效系統的研究是本論文的目的所在。在文中，我們首先介紹了基礎聲學與聲像定位理論，分析了優先效應、耳廓效應、ITD、IID、頭部相關轉移函數、反射與混響等因素對聽覺定位的影響，接著對用立體聲揚聲器虛擬音效的技術進行理論分析和推導，對揚聲器的串音消除技術做了比較深入的探討。為了確認本系統架構的可行性，我們通過電腦用MATLAB做了模擬實驗，得到了比較理想的聽覺效果。我們由相位觀察經系統處理後的音訊變化及主觀音訊品質的評量其環繞效果，在兩種不同種類的音訊測驗中平均都會有加強環繞音場的效果，虛擬環繞音效系統通過對人的聽覺心理特性的模擬，利用一對揚聲器就能在普通音源的重放中實現三維環繞聲。這類系統的架構簡單，也能達到一定的聽覺效果，在居家較為狹小的家庭或是不宜採用多聲道系統的場合(如多媒體電腦)具有相當廣泛的應用前景。 Nowadays the multimedia applications of the 3D virtual reality are more and more popular. Although most application focus on 3D video, the combination of 3D video and audio processing can enrich the experience of users. Most of the traditional stereo systems, which can only maintain partial sound spatial distribution, provide listeners with the ability to distinguish the two-dimensional plane, not the performance of three-dimensional spatial acoustics. Multi-channel surround sound systems come about to solve this problem, but this kind of systems require the sound source to be treated specially, also it has severe restrictions to hardware and environment. All of these restrain its applications. In view of this situation, researchers developed the theory of virtual surround sound (VSS) and carry about many research studies. The objective of this thesis is to explore and create a dual-channel virtual surround sound system. The thesis first introduces fundamentals of acoustics and human sound location theory, including the cues of precedence effect, Pinna effect, ITD, IID, head related transfer function (HRTF), reflection and reverberation. Then we propose a virtual sound source system using two loudspeakers, which can perform crosstalk cancellation. To confirm the feasibility of this method, we do experiments by computer simulations using MATLAB and obtain satisfactory effects. We evaluate the system by observing the phase between two channels after the proposed processing and the subjective audio quality of the assessment on the surround effect. In three different types of audio tests, audio surround effect is significantly enhanced. Through simulation of humans spatial hearing characteristics, VSS system can reproduce normal sound source’s 3D surround effect using a pair of loudspeakers. This system has simple configuration and is able to produce lifelike sense. It has great potential to provide extensive applications in small room that is not suitable for multi-channel surround systems.
Appears in Collections:	[Executive Master of Communication Engineering] Electronic Thesis & Dissertation

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