Abstract:

A virtual acoustic pointer may provide a natural way of indicating the apparent position of virtual auditory stimuli. In a localization experiment, listeners were instructed to place an acoustic pointer at the same apparent position as a virtual target. The pointer was generated by filtering a click train (100 ms) with equalized minimum-phase head-related transfer functions (HRTFs). Listeners controlled the position of the pointer with a hand-held stick that rotated about a fixed point. In the baseline condition the target, a 100 ms noise burst, was filtered with the same HRTFs as the pointer. In other conditions, the HRTFs of the target were modeled with three, five, or seven principal components. Target and pointer were never presented simultaneously. Listener's judgments with the pointer were more accurate than those reported in previous studies requiring verbal responses. The acoustic pointer also seemed to help listeners to resolve front-back confusions. With fewer than seven principal components used to synthesize stimuli, subjects made substantially more front-back confusions and many more errors in elevation, in agreement with previous studies. The results suggest that an acoustic pointer allows more subtle cues for sound localization to be studied. [Work supported by TNO.]