Analysis and enhancement of multiactuator panels for wave field synthesis reproduction.

Abstract

This thesis addresses the development and enhancement of Multiactuator Panels (MAPs) with emphasis on the application to Wave Field Synthesis (WFS) reproduction. MAPs can be used alternatively to dynamic loudspeaker arrays for WFS with added benefits. However, since MAPs are panels of finite extent, excited mechanically on several points, there are structural and geometric issues that must be addressed to guarantee that all exciters are acting evenly to form an effective loudspeaker array for WFS. This aim is addressed by means of a methodology for the analysis of sound field radiation in the space-time domain that has been proposed and validated in this thesis. This research has produced a number of key conclusions. The proposed method analyzes aliasing artifacts in a graphical representation showing the distribution of radiated energy over space. In a comparative study between MAPs of different dimensions and dynamic loudspeaker arrays, the main conclusion, with significant practical consequences, is that the wave field created by large panels contains less artifacts than that of equivalent small panels. The effect of panel boundaries on the quality of the wave field has also been addressed by comparing several edge boundary conditions with multiple elastic materials. The main conclusion drawn from this study is the convenience of using elastic boundary conditions that can form a viable technology for a MAP frame while showing a proper acoustic radiation. Boundaries also affect the response of exciters near edges that must conveniently be equalized for a response similar to that of middle exciters. To that end, an efficient equalization filtering process has been introduced that takes into account the particular exciter distribution on a panel for considerably reducing the measurement points. Finally, an optimized large MAP has been designed and tested, incorporating the enhancements previously discussed and facilitating the combination of WFS with video projection for immersive multimedia applications.