JMIR Publications

ABSTRACT

In order to present virtual sound sources via headphones spatially, head-related transfer functions (HRTFs) can be applied to audio signals. In this so-called binaural virtual acoustics, the spatial perception may be degraded if the HRTFs deviate from the true HRTFs of the listener. In this study, participants wearing virtual reality headsets performed a listening test on the 3D audio perception of virtual audiovisual sound scenes, thus enabling us to investigate the necessity and influence of the individualization of HRTFs. For the evaluation, 39 subjects rated individualized and non-individualized HRTFs in an audiovisual virtual scene on the basis of five perceptual qualities: localizability, front-back position, externalization, tone color, and realism. The virtual reality listening experiment included two tests: In the first test, subjects evaluated their own and the general HRTF from the MIT KEMAR database and in the second test, their own and two other non-individualized HRTFs from the HRTF database of the Acoustic Research Institute of the Austrian Academy of Sciences. For the experiment, two subject-specific, non-individualized HRTFs with a minimal and maximal localization error deviation were selected according to the localization model in sagittal planes. With Wilcoxon signed-rank test (test 1) and ANOVA (test 2) the results show significance in all perceptual qualities, except for the front-back position between own and minimal-deviant-non- individualized HRTF. This suggests that sounds filtered by individualized HRTFs compared to non-individualized HRTFs are considered easier to localize, easier to externalize, more natural in timbre and more realistic.