Abstract:
Results from studies of the apparent positions of virtual and real sound sources conducted over the past 5 years reveal large individual differences. To characterize these differences in global terms such as accuracy or variance does not tell the whole story. Listeners differ in the extent to which they make front--back or back--front confusions, the extent to which they report apparent positions above or below the horizontal plane, the resistance of their judgments of apparent position to interaural level imbalance, and other factors. It seems clear that some of these differences might be traced to differences in outer-ear acoustics. Since pinna shapes vary tremendously from person to person, there are large individual differences in the resulting head-related transfer functions (HRTFs). The cues provided by the direction-dependency of HRTFs are known to be important, especially for determining apparent source elevation. HRTFs lacking in detail provide ineffective cues and thus listeners must adopt differing strategies for combining HRTF cues with other cues to determine source position. Unfortunately detailed analyses of both HRTF differences and differences in localization behavior does not reveal a simple relationship. [Work supported by NASA and NIDCD.]