Perceptual attributes for the comparison of head-related transfer functions

Abstract

The benefit of using individual head-related transfer functions (HRTFs) in binaural audio is well documented with regards to improving localization precision. However, with the increased use of binaural audio in more complex scene renderings, cognitive studies, and virtual and augmented reality simulations, the perceptual impact of HRTF selection may go beyond simple localization. In this study, the authors develop a list of attributes which qualify the perceived differences between HRTFs, providing a qualitative understanding of the perceptual variance of non-individual binaural renderings. The list of attributes was designed using a Consensus Vocabulary Protocol elicitation method. Participants followed an Individual Vocabulary Protocol elicitation procedure, describing the perceived differences between binaural stimuli based on binauralized extracts of multichannel productions. This was followed by an automated lexical reduction and a series of consensus group meetings during which participants agreed on a list of relevant attributes. Finally, the proposed list of attributes was then evaluated through a listening test, leading to eight valid perceptual attributes for describing the perceptual dimensions affected by HRTF set variations.

A Perceptual Evaluation of Individual and Non-Individual HRTFs: A Case Study of the SADIE II Database

“…Pearce examined the search terms used in online sound effect libraries and compiled a list of the most popular discriminators [35]. Simon was a little more specific and identified eight qualities for describing the perceived differences between non-individual HRTF sets in binaural renderings [36]. He first followed an individual vocabulary profiling procedure, similar to Lokki, before refining his terms through a series of focus groups.…”

“…Koivuniemi [32], Lindau [33], Lokki [34], Pearce [35] and Simon [36] all identify brightness (/darkness) as the abundance of high (/low) frequencies. We use the same definition.…”

“…Whilst this is a more ecological than noise, it is relatively band limited and lacks low frequencies especially. The stimuli used should represent examples of everyday bianural audio and as such should elicit the same or at least similar perceptual characteristics [36]. For example, whilst it would be quite unusual to discuss the brightness of radio static, a similar discussion about the sound of a piano would be relatively common.…”

Influence of head tracking on the externalization of speech stimuli for non-individualized binaural synthesis

“…Moreover, front-back confusions might occur frequently (Hartmann and Wittenberg, 1996). Perceptual attributes linked to HRTF variations have been recently detailed in Simon et al (2016).…”

Quality assessment of acoustic environment reproduction methods for cinematic virtual reality in soundscape applications

“…Because there were significant differences observed when evaluating spatial attributes using non-individualized HRTFs with expert listeners [80,81], further investigation into the degree to which non-expert listeners were affected when the binaural tracks were rendered with individualized HRTFs [82,83] and/or headphones with frontal emitters [7] could shed light on studies involving non-expert participants (i.e. soundscape).…”