平面喇叭系統之研發：設計、測試、改良

Abstract

摘要 本文旨在對平板式喇叭作深入的分析，探討平面喇叭的基本原理以及其優於傳統喇叭的特點。平面喇叭主要是由一片輕巧的薄板和一個或數個慣性致動器所組成，其設計的最佳化就是盡可能的讓平板產生隨機的振動模態。本文也發展出一套平面喇叭性能特性的模擬工具，利用有限元素分析法和機電類比電路求得平面喇叭在聲場的輻射效果。平面喇叭的設計流程以及其性能量測包括頻率響應、方向性、敏感度、效率和失真率也都會陸陸續續的提到。而這些性能量測的結果明顯的指出平面喇叭所具有的重大缺陷：敏感度較差尤以低頻的時候更為嚴重。因此在本文的最後利用數位和類比的電子補償來補足這一方面的缺憾，實驗的結果證明在經由電子補償之後平面喇叭的性能表現的確明顯的加強。

ABSTRACT In this paper, the panel loudspeaker is investigated in terms of structural vibrations and acoustic radiation. A panel loudspeaker consists primarily of a light panel and one or several inertia exciters. The panel is optimally designed to vibrate as randomly as possible. Simulation tools are developed for system integration of panel loudspeakers. In particular, electro-mechanical analogy, finite element analysis and fast Fourier transform are employed to predict panel vibration and the acoustical radiation. Design procedures are described. Performance indices including frequency response, directional response, sensitivity, efficiency and distortion are evaluated and compared with a conventional loudspeaker. It is found in experimental results that, even though the panel loudspeakers provide a number of advantages over conventional loudspeakers, the panel loudspeakers suffer from an inherent deficiency of poor sensitivity especially at low frequency. Thus digital and analog compensation using H2 model matching is employed to alleviate the problem. The experimental results show significant improvement of the compensated system.