(A) study on the acoustic design of sound source array by the inverse approach

Abstract

This research suggested an acoustic source array design method based on the inverse approach using the acoustical holography with modification for design problem considering the preparation of target field data and actual source characteristics. In the design of source array, the distribution of pressure response at specific field points is the constraint of the problem and the source condition describing the relative magnitude and phase between sources is the object function of the problem. The whole procedure of the application consists of the following three stages: First, a condition of desired sound field should be set as the constraint. Second, the geometry and boundary condition of source array system and target field, i.e., points in sound field of concern, are modeled by the boundary elements or the equivalent source methods. Actual characteristics of source and space can be considered to generate the accurate condition of target field. Finally, the source parameters are inversely calculated by the backward projection. Several problems that are considered for the design source array are also discussed. The first of these involves the preparation of the target sound field data. In a source reconstruction problem, the sound field and source exist collectively; however, in the case of a source design problem, the sound field is not realized in the design stage. For this reason, the preparation of a physically reasonable and realizable target field is important. An additional topic to be considered in this area is the modeling of the actual source characteristics. In many sound control methods, an ideal source assumption is applied; however, conventional loudspeakers have many differences with ideal sources. They have specific directional patterns and frequency responses that affect the result as object on the sound field. These types of differences create errors between the actual generated field and the target field. Therefore, the exact modeling of the ...