Rapid head-related transfer function adaptation using a virtual auditory environment

Abstract

The paper reports on the ability of people to rapidly adapt in localizing virtual sound sources in both azimuth and elevation when listening to sounds synthesized using non-individualized head-related transfer functions (HRTFs). Participants were placed within an audio-kinesthetic Virtual Auditory Environment (VAE) platform that allows association of the physical position of a virtual sound source with an alternate set of acoustic spectral cues through the use of a tracked physical ball manipulated by the subject. This set-up offers a natural perception-action coupling, which is not limited to the visual field of view. The experiment consisted of three sessions: an initial localization test to evaluate participants' performance, an adaptation session, and a subsequent localization test. A reference control group was included using individual measured HRTFs. Results show significant improvement in localization performance. Relative to the control group, participants using non-individual HRTFs reduced localization errors in elevation by 10° with three sessions of 12 min. No significant improvement was found for azimuthal errors or for single session adaptation.

Relearning Auditory Spectral Cues for Locations Inside and Outside the Visual Field

“…The possibility that other sensorimotor mechanisms maybe involved in the accommodation to altered spectral cues was raised when these observations were first made (Hofman et al 1998). Prior to the current experiment, however, there have been no studies that have explicitly looked at the capacity to accommodate to new spectral cues for locations outside the visual field, let alone to the possible role of sensorimotor mechanisms in this process (see however, Zahorik et al 2006;Parseihian and Katz 2012). In this study, we have shown that the extent of accommodation (Fig.…”

Multimodal Perceptual Training for Improving Spatial Auditory Performance in Blind and Sighted Listeners

“…Most of the subjects reached the same level of localisation performance as their counterparts from the control group (who listened to 3D sounds filtered with individualised HRTFs) after performing several training sessions (Parseihian, Katz, 2012;Blum et al, 2004). Moreover, the training procedure proved to have long-term effects, as the listeners recorded similar levels of performance even one month after the experiment had taken place (Honda et al, 2007).…”

“…The sound localication cues contained in the HRTF spectrum are related with the lateralisation of the source and with elevation discrimination (Parseihian, Katz, 2012). As in the literature the term "lateralisation" has been used to describe the identification of virtual sound sources rendered over headphones, in this study we will use the term "localisation" to indicate the discrimination of target sound sources in virtual auditory displays.…”

“…As the HRTFs significantly depend on the anatomical characteristics of the external auditory system (the size and shape of the pinna, head, and torso), they noticeably vary among individuals, being highly individualised to each listener apart (Dellepiane et al, 2008). Therefore, using non-individualised HRTFs in virtual auditory environments results in localisation errors, lateralisation artifacts, perceptual distortions, such as front-back and back front-confusions (situation when the listener perceives the sound coming from the front as originating from the back and vice-versa) and non-externalized auditory images (Parseihian, Katz, 2012;Meshram et al, 2014).…”

“…As generating individualised sets of HRTFs involves a long and complicated measurement process, in order to minimise the sound localisation errors and help listeners to adapt to virtual auditory environ-ments, many experiments have used training methods aimed at recalibrating the auditory system to altered hearing conditions and improving perceptual learning (Parseihian, Katz, 2012;Mendonça, 2014). The adaptive plasticity that occurs after the loss of a sensory modality (especially sight) is the result of multimodal perceptual cues and spatial attention (the ability to focus on specific stimuli of the environment) (Strelnikov et al, 2011).…”