Usability of Individualized Head-Related Transfer Functions in Virtual Reality: Empirical Study With Perceptual Attributes in Sagittal Plane Sound Localization.

Claudia Jenny,Christoph Reuter

doi:10.2196/17576

Abstract

BackgroundIn 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.ObjectiveIn this study, participants wearing virtual reality (VR) headsets performed a listening test on the 3D audio perception of virtual audiovisual scenes, thus enabling us to investigate the necessity and influence of the individualization of HRTFs. Two hypotheses were investigated: first, general HRTFs lead to limitations of 3D audio perception in VR and second, the localization model for stationary localization errors is transferable to nonindividualized HRTFs in more complex environments such as VR.MethodsFor the evaluation, 39 subjects rated individualized and nonindividualized HRTFs in an audiovisual virtual scene on the basis of 5 perceptual qualities: localizability, front-back position, externalization, tone color, and realism. The VR listening experiment consisted of 2 tests: in the first test, subjects evaluated their own and the general HRTF from the Massachusetts Institute of Technology Knowles Electronics Manikin for Acoustic Research database and in the second test, their own and 2 other nonindividualized HRTFs from the Acoustics Research Institute HRTF database. For the experiment, 2 subject-specific, nonindividualized HRTFs with a minimal and maximal localization error deviation were selected according to the localization model in sagittal planes.ResultsWith the Wilcoxon signed-rank test for the first test, analysis of variance for the second test, and a sample size of 78, the results were significant in all perceptual qualities, except for the front-back position between own and minimal deviant nonindividualized HRTF (P=.06).ConclusionsBoth hypotheses have been accepted. Sounds filtered by individualized HRTFs are considered easier to localize, easier to externalize, more natural in timbre, and thus more realistic compared to sounds filtered by nonindividualized HRTFs.

Highlights

Theories The question raised in the article, “Binaural Technique: Do We Need Individual Recordings?” by Møller et al [1], is one that many researchers and developers still ask themselves
The first hypothesis of our study that general head-related transfer function KEMAR (HRTF) lead to limitations of 3D audio perception in virtual reality (VR) was confirmed
The reverberation can be integrated as an additional variable building on this work. Both hypotheses have been accepted: first, general HRTFs lead to limitations of 3D audio perception in VR and second, the localization model for stationary localization errors is transferable to nonindividualized HRTFs in more complex environments such as VR

Summary

Introduction

Theories The question raised in the article, “Binaural Technique: Do We Need Individual Recordings?” by Møller et al [1], is one that many researchers and developers still ask themselves. 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. It is assumed that binaural and monaural spectral features are processed largely independently of each other [22,23] While binaural disparities such as interaural time and level differences play an important role in sound localization in the lateral dimension (left-right), monaural spectral cues are known to determine the perceived position of the sound source in the sagittal planes (front-back and up-down).

Methods

Results

Discussion

Conclusion