Effects of ear coverage and reflected sound on the localization of sound

Previous research has shown that listeners wearing helmets with greater ear coverage perform worse on localization tasks. However, the helmets studied were selected from those commonly in use and differed in suspension systems and profiles. Three versions of the same helmet design, differing only in the ear coverage (0%, 50%, 100%), were compared in this study. Sounds were presented from 12 azimuthal locations spaced 30 deg apart in the presence of a white noise masker. Twelve listeners completed a localization task while wearing each of the helmets as well as with no helmet in two different acoustic environments. As ear coverage increased, localization performance decreased. The effects of early reflections, though small, were consistent across the different coverage conditions. The effect of ear coverage and its interaction with the acoustic environment will be discussed in terms of its significance for real-world environments. In addition, head-related transfer-functions (HRTFs) were measured for each listener in each of the head conditions. A model of localization performance based on changes to the HRTF will be described and applied to the collected data.