音場空間等化處理

Abstract

這篇論文主要在討論如何設計多聲道的音場等化系統，以消除聆聽空間所 造成的不良效應。這些不良效應包括房間的反射、串音消除等。因此所面 對的不良音場不再是單一個濾波器，而是每個元素皆代表一個濾波器的矩 陣。吾人將針對單聲道、雙聲道乃至多聲道做探討，以一些合理的方法， 找出其等化系統。而接收端的位置變動對等化結果造成的影響，也須要加 以考慮，我們將會以矩陣擾動的方式來分析。吾人對斷續的接收點擴大為 一個面積，進而研究對一個區域等化的問題。吾人亦考慮利用適應性濾波 器來降低運算量及複雜度，以便能簡單的去製作。最後將會利用電腦模擬 來檢驗推導的演算法是否符合我們想要的結果。 This thesis describes a general theoretical basis for the design of multichannel acoustical spatial equalizers to provide a good acoustical sound field. We aim to equalize both the response of the loudspeakers and the listening room as well as to cancel the acoustic crosstalk. The work presented is applied first to the single-channel, two-channel and then extended to the multi-channel case. Several methods to obtain the solution of the equalization system are provided. Extension of acoustical equalization over a listening area is also discussed. Because the room impulse response varies with location, the issue of mismatched equalization based on matrix perturbation theory is addressed. Multi-channel equalization using adaptive filters offers an attractive solution to the reduction of computation and complexity, we will use the LMS approach to design the digital filters. Finally, computer simulations will justify the algorithms for acoustical spatial equalization.