A New Method for Localization Studies

Abstract

Many scientific studies investigate and technical applications use the acoustical localization in the field of vision. Therefore it is suitable to display the perceived auditory direction by a light point. In formerly known methods subjects use a hand-held light pointer or a pointer mounted on a revolvable axle in front of them. However, the subject’s motor system or the optical parallax may influence the results of those techniques. The calibration of the system and data logging also turn out to be difficult. The proposed new method utilizes a laser pointer with a deflection unit instead, which is controlled by a computer. Subjects enter the perceived sound direction with a trackball. The laser spot moves according to the rotation of the ball smoothly on a defined track. A complicated mechanical calibration can be avoided by calibrating the deflection unit by a computer. The intuitive experimental operation and the high resolution of the system make this method particularly suitable for localization research in audiology, psychoacoustics, and virtual acoustics. The symmetric, bimodal outlay of the experimental task reduces interaction effects between different modalities. Localization results for variable and fixed initial laser position obtained by this method are presented and compared to results acquired by other methods. PACS no. 43.66.Yw, 43.66.Qp, 43.66.Pn 1.