SOUND EQUALIZATION IN ENCLOSURES USING MODAL RECONSTRUCTION

The equalization of complex sound pressure in an enclosure is investig ated in this paper. The sound held in the enclosure is modeled with th e sum of a series of modes. This sound held is controlled by multiple sources distributed in the enclosure so that a certain region in the e nclosure has a desired complex sound pressure. First, the optimum solu tion which minimizes the average potential energy of the error pressur e over the region is derived, where the error is defined as the differ ence between the desired sound pressure and the sound pressure caused by the sources. By using the optimum solution, the achievable best per formance can be known for the given region and the source distribution . The optimum solution can also be a useful tool for finding an effect ive source distribution since the performance of the optimum solution depends only on the source distribution. Furthermore, the eigenvalues of the source coupling matrix, which appears in the derivation of the optimum solution, indicates the effectiveness of the source distributi on. The effectiveness of source distribution is discussed with nine ex amples of source distributions in a two-dimensional enclosure. The mul tipoint equalization method to approximate the optimum solution is als o discussed for the practical use. (C) 1995 Acoustical Society of Amer ica.