Controlling a distance from linear loudspeaker arrays to a listening point by using tangent line method

A technique for confining the acoustic fields near loudspeaker arrays is proposed for personal audio systems. The proposed technique is based on tangent line method (TLM), which enables the production of circular acoustic beams. The produced beams are focused at a point designated as the listening point. Performance of the TLM-based method and acoustic contrast control (ACC) is compared. In terms of the acoustic contrast and array effort, the TLM-based method is not superior to the ACC but is comparable with the ACC under certain conditions. The advantage of the TLM-based method is the simplicity in signal processing.