Optimal design of panel speaker array with omnidirectional characteristics

Abstract

A panel speaker system intended for a projection screen is developed. Like other sound sources with large dimension, the panel speaker has a beaming problem in high frequencies. To alleviate the problem, panel speakers are integrated into an array, with optimal electronic compensation for omnidirectional response and array efficiency. The heart of the design procedure is a three-stage optimization scheme involving two nonlinear and nonconvex objectives. The process is interactive, allowing the array coefficients to be tailored so that the specifications of directional response can be met. The optimal design of panel speaker array is then implemented by using a multichannel digital signal processor. In addition, a Hilbert transformer is required to produce the quadrature components of the array coefficients. A small array and a large matrix were constructed to validate the implemented array signal processing system. The experimental results indicate that, without degradation of efficiency, the proposed optimization technique in conjunction with electronic compensation is effective in attaining omnidirectional radiation property. (C) 2002 Acoustical Society of America.