Real‐virtual equivalent auditory localization with head motion.

Abstract

Several researchers have shown that individualized head related transfer functions (HRTFs) can be used to produce virtual sounds that are equivalent in terms of localization to free field sounds. Thus far, however, these results have only been shown in studies that have required listeners to keep their heads stationary during the playback of the virtual sounds. In this study, we investigated the performance limits of a virtual auditory display system that incorporated individualized HRTFs but allowed free head motion during the localization process. One key aspect of the system is a high‐speed HRTF measurement process that allowed a full set of individualized HRTFs to be measured in less than 4 min. This made it possible to make an HRTF recording and complete a localization task using the resulting HRTFs within the same 30‐min experimental session. The results show that equivalent free‐field and virtual localization performance was achieved when the virtual sounds were generated in the same session using specially‐designed open‐ear headphones that did not need to be removed during the headphone equalization process. This indicates that equivalent real‐virtual closed‐loop localization is possible even with the truncated, interpolated, minimum‐phase HRTF filters that are required for practical, real‐world virtual audio systems.