Cho W., Ih J.

An inverse method was suggested for the design of source array to realize the desired sound field. The basic idea was stemmed from the source identification technique, which employs the measured field data to reconstruct the vibro-acoustic parameters on the source surface. In our problem, the pressure at specific points in the sound field was set as constraints for the desired sound field: surface points at the source plane became elementary sources. The whole procedure was conducted in three steps: First, the constraint for a desired sound field was set. The constraints could be either any desired field condition or measured data obtained in a target space. Two types of constraints could be classified: parameters related to sound quality and those related to the distributed characteristic information at a specified location. Second, the feasibility test was conducted and the required number of sources to describe the target field was determined as well as the elementary source size. Finally, the source parameters were calculated using the back propagation technique which has been used in the inverse source identification. Among many methods, the inverse boundary element method was adopted to obtain the source parameters. The present method can be used to implement both global control and zonal control depending on the spectral nature and spatial extent of constraints. It is thought that the present method can be also used for generating a virtual sound field at an arbitrary space.