矩陣式平面喇叭銀幕視聽系統

Abstract

摘要 近來大眾對大型影音系統的需求快速的提高. 所以我們便想整合了投影技術, 平面喇叭, 和陣列訊號處理的技巧, 架構一個簡單、且具有多功能的影音系統. 我們使用平面喇叭作為光學投影板. 並結合陣列訊號處理, 改進大平面喇叭高頻有指向性的問題, 同時提供一些附加的功能. 因為系統還在建構中, 在這篇論文裡將只討論陣列訊號處理在聲音上面的應用. 在這篇論文中我們討論了許多陣列訊號處理的方法, 包含兩個主題兒－具方向性陣列及無指向性陣列. 具方向性陣列會將聲音的能量往一固定方向輻射. 而無指向性陣列卻使聲音均勻的分布在空間中. 因為在無指向性陣列的設計中, 常會有低輻射效率的問題, 所以我們發展出一套最佳化的方法來解決這問題. 這最佳化的方法提供了一高輻射效率及均勻的輻射聲場. 在硬體實作中我們一共架構了一個之5×1的喇叭陣列, 及一3×3的喇叭陣列. 為了量測聲壓我們也架構了一套自動化量測系統. 我們也會秀出量測的結果. 而實驗的結果也驗證了陣列訊號處理在喇叭的應用.

Abstract Recently, the demand of a large scale audiovideo system is rising rapidly. We wish to construct an audiovideo system integrating the technologies of projecting methods, panel speaker, and array signal process together. Using the panel speaker to be projection screen give a simple system. Using array signal processing improves the directiviy problem for large panel and gives more audio functions. Since the system is still being developed, we only discuss the application of array signal processing to audio. In this paper we discuss various methods which involve two objectives, directional arrays and omnidirectional arrays. A directional array radiates sound power to a secific direction. An omnidirectional array makes the sound power distribution uniformly. Because there is a problem of low radiation efficiency in the omnidirectional array design, we develop an optimization for omnidirectional arrays. This optimization gives a solution with high radiation efficiency and flat spectrum. We implement a 5×1 speaker array and 3×3 speaker array. We also implement a system for sound pattern measurement. The experimental result is also given in this paper. From the experimental result, we verify the proposed array signal processing techniques.