scholarly journals Short-term effects of sound localization training in virtual reality

2017 ◽  
Author(s):  
Mark A. Steadman ◽  
Chungeun Kim ◽  
Jean-Hugues Lestang ◽  
Dan F. M. Goodman ◽  
Lorenzo Picinali

ABSTRACTHead-related transfer functions (HRTFs) capture the direction-dependant way that sound interacts with the head and torso. In virtual audio systems, which aim to emulate these effects, non-individualized, generic HRTFs are typically used leading to an inaccurate perception of virtual sound location. Training has the potential to exploit the brain’s ability to adapt to these unfamiliar cues. In this study, three virtual sound localization training paradigms were evaluated; one provided simple visual positional confirmation of sound source location, a second introduced game design elements (“gamification”) and a final version additionally utilized head-tracking to provide listeners with experience of relative sound source motion (“active listening”). The results demonstrate a significant effect of training after a small number of short (12-minute) training sessions, which is retained across multiple days. Gamification alone had no significant effect on the efficacy of the training, but active listening resulted in a significantly greater improvements in localization accuracy. In general, improvements in virtual sound localization following training generalized to a second set of non-individualized HRTFs, although some HRTF-specific changes were observed in polar angle judgement for the active listening group. The implications of this on the putative mechanisms of the adaptation process are discussed.

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mark A. Steadman ◽  
Chungeun Kim ◽  
Jean-Hugues Lestang ◽  
Dan F. M. Goodman ◽  
Lorenzo Picinali

AbstractHead-related transfer functions (HRTFs) capture the direction-dependant way that sound interacts with the head and torso. In virtual audio systems, which aim to emulate these effects, non-individualized, generic HRTFs are typically used leading to an inaccurate perception of virtual sound location. Training has the potential to exploit the brain’s ability to adapt to these unfamiliar cues. In this study, three virtual sound localization training paradigms were evaluated; one provided simple visual positional confirmation of sound source location, a second introduced game design elements (“gamification”) and a final version additionally utilized head-tracking to provide listeners with experience of relative sound source motion (“active listening”). The results demonstrate a significant effect of training after a small number of short (12-minute) training sessions, which is retained across multiple days. Gamification alone had no significant effect on the efficacy of the training, but active listening resulted in a significantly greater improvements in localization accuracy. In general, improvements in virtual sound localization following training generalized to a second set of non-individualized HRTFs, although some HRTF-specific changes were observed in polar angle judgement for the active listening group. The implications of this on the putative mechanisms of the adaptation process are discussed.


2021 ◽  
Vol 263 (5) ◽  
pp. 1488-1496
Author(s):  
Yunqi Chen ◽  
Chuang Shi ◽  
Hao Mu

Earphones are commonly equipped with miniature loudspeaker units, which cannot transmit enough power of low-frequency sound. Meanwhile, there is often only one loudspeaker unit employed on each side of the earphone, whereby the multi-channel spatial audio processing cannot be applied. Therefore, the combined usage of the virtual bass (VB) and head-related transfer functions (HRTFs) is necessary for an immersive listening experience with earphones. However, the combining effect of the VB and HRTFs has not been comprehensively reported. The VB is developed based on the missing fundamental effect, providing that the presence of harmonics can be perceived as their fundamental frequency, even if the fundamental frequency is not presented. HRTFs describe the transmission process of a sound propagating from the sound source to human ears. Monaural audio processed by a pair of HRTFs can be perceived by the listener as a sound source located in the direction associated with the HRTFs. This paper carries out subjective listening tests and their results reveal that the harmonics required by the VB should be generated in the same direction as the high-frequency sound. The bass quality is rarely distorted by the presence of HRTFs, but the localization accuracy is occasionally degraded by the VB.


2021 ◽  
Vol 25 ◽  
pp. 233121652110161
Author(s):  
Julian Angermeier ◽  
Werner Hemmert ◽  
Stefan Zirn

Users of a cochlear implant (CI) in one ear, who are provided with a hearing aid (HA) in the contralateral ear, so-called bimodal listeners, are typically affected by a constant and relatively large interaural time delay offset due to differences in signal processing and differences in stimulation. For HA stimulation, the cochlear travelling wave delay is added to the processing delay, while for CI stimulation, the auditory nerve fibers are stimulated directly. In case of MED-EL CI systems in combination with different HA types, the CI stimulation precedes the acoustic HA stimulation by 3 to 10 ms. A self-designed, battery-powered, portable, and programmable delay line was applied to the CI to reduce the device delay mismatch in nine bimodal listeners. We used an A-B-B-A test design and determined if sound source localization improves when the device delay mismatch is reduced by delaying the CI stimulation by the HA processing delay (τHA). Results revealed that every subject in our group of nine bimodal listeners benefited from the approach. The root-mean-square error of sound localization improved significantly from 52.6° to 37.9°. The signed bias also improved significantly from 25.2° to 10.5°, with positive values indicating a bias toward the CI. Furthermore, two other delay values (τHA –1 ms and τHA +1 ms) were applied, and with the latter value, the signed bias was further reduced in some test subjects. We conclude that sound source localization accuracy in bimodal listeners improves instantaneously and sustainably when the device delay mismatch is reduced.


2018 ◽  
Author(s):  
Axel Ahrens ◽  
Kasper Duemose Lund ◽  
Marton Marschall ◽  
Torsten Dau

AbstractTo achieve accurate spatial auditory perception, subjects typically require personal head-related transfer functions (HRTFs) and the freedom for head movements. Loudspeaker-based virtual sound environments allow for realism without individualized measurements. To study audio-visual perception in realistic environments, the combination of spatially tracked head mounted displays (HMDs), also known as virtual reality glasses, and virtual sound environments may be valuable. However, HMDs were recently shown to affect the subjects’ HRTFs and thus might influence sound localization performance. Furthermore, due to limitations of the reproduction of visual information on the HMD, audio-visual perception might be influenced. Here, a sound localization experiment was conducted both with and without an HMD and with a varying amount of visual information provided to the subjects. Furthermore, interaural time and level difference errors (ITDs and ILDs) as well as spectral perturbations induced by the HMD were analyzed and compared to the perceptual localization data. The results showed a reduction of the localization accuracy when the subjects were wearing an HMD and when they were blindfolded. The HMD-induced error in azimuth localization was found to be larger in the left than in the right hemisphere. Thus, the errors in ITD and ILD can only partly account for the perceptual differences. When visual information of the limited set of source locations was provided, the localization error induced by the HMD was found to be negligible. Presenting visual information of hand-location, room dimensions, source locations and pointing feedback on the HMD revealed similar effects as previously shown in real environments.


2020 ◽  
Author(s):  
V. Gaveau ◽  
A. Coudert ◽  
R. Salemme ◽  
E. Koun ◽  
C. Desoche ◽  
...  

AbstractIn everyday life, localizing a sound source in free-field entails more than the sole extraction of monaural and binaural auditory cues to define its location in the three-dimensions (azimuth, elevation and distance). In spatial hearing, we also take into account all the available visual information (e.g., cues to sound position, cues to the structure of the environment), and we resolve perceptual ambiguities through active listening behavior, exploring the auditory environment with head or/and body movements. Here we introduce a novel approach to sound localization in 3D named SPHERE (European patent n° WO2017203028A1), which exploits a commercially available Virtual Reality Head-mounted display system with real-time kinematic tracking to combine all of these elements (controlled positioning of a real sound source and recording of participants’ responses in 3D, controlled visual stimulations and active listening behavior). We prove that SPHERE allows accurate sampling of the 3D spatial hearing abilities of normal hearing adults, and it allowed detecting and quantifying the contribution of active listening. Specifically, comparing static vs. free head-motion during sound emission we found an improvement of sound localization accuracy and precisions. By combining visual virtual reality, real-time kinematic tracking and real-sound delivery we have achieved a novel approach to the study of spatial hearing, with the potentials to capture real-life behaviors in laboratory conditions. Furthermore, our new approach also paves the way for clinical and industrial applications that will leverage the full potentials of active listening and multisensory stimulation intrinsic to the SPHERE approach for the purpose rehabilitation and product assessment.


2019 ◽  
Vol 6 (7) ◽  
pp. 190423 ◽  
Author(s):  
L. Papet ◽  
N. Grimault ◽  
N. Boyer ◽  
N. Mathevon

As top predators, crocodilians have an acute sense of hearing that is useful for their social life and for probing their environment in hunting situations. Although previous studies suggest that crocodilians are able to localize the position of a sound source, how they do this remains largely unknown. In this study, we measured the potential monaural sound localization cues (head-related transfer functions; HRTFs) on alive animals and skulls in two situations, both mimicking natural positions: basking on the land and cruising at the interface between air and water. Binaural cues were also estimated by measuring the interaural level differences (ILDs) and the interaural time differences (ITDs). In both conditions, HRTF measurements show large spectral variations (greater than 10 dB) for high frequencies, depending on the azimuthal angle. These localization cues are influenced by head size and by the internal coupling of the ears. ITDs give reliable information regarding sound-source position for low frequencies, while ILDs are more suitable for frequencies higher than 1.5 kHz. Our results support the hypothesis that crocodilian head morphology is adapted to acquire reliable localization cues from sound sources when outside the water, but also when only a small part of their head is above the air–water interface.


2007 ◽  
Vol 16 (2) ◽  
pp. 157-171 ◽  
Author(s):  
Matti Gröhn ◽  
Tapio Lokki ◽  
Tapio Takala

In a CAVE-like virtual environment spatial audio is typically reproduced with amplitude panning on loudspeakers behind the screens. We arranged a localization experiment where the subjects' task was to point to the perceived location of a sound source. Measured accuracy for a static source was as good as the accuracy in previous headphone experiments using head-related transfer functions. We also measured the localization accuracy of a moving auditory stimulus. The accuracy was decreased by an amount comparable to the minimum audible movement angle.


1999 ◽  
Vol 58 (3) ◽  
pp. 170-179 ◽  
Author(s):  
Barbara S. Muller ◽  
Pierre Bovet

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3446
Author(s):  
Muhammad Usman Liaquat ◽  
Hafiz Suliman Munawar ◽  
Amna Rahman ◽  
Zakria Qadir ◽  
Abbas Z. Kouzani ◽  
...  

Sound localization is a field of signal processing that deals with identifying the origin of a detected sound signal. This involves determining the direction and distance of the source of the sound. Some useful applications of this phenomenon exists in speech enhancement, communication, radars and in the medical field as well. The experimental arrangement requires the use of microphone arrays which record the sound signal. Some methods involve using ad-hoc arrays of microphones because of their demonstrated advantages over other arrays. In this research project, the existing sound localization methods have been explored to analyze the advantages and disadvantages of each method. A novel sound localization routine has been formulated which uses both the direction of arrival (DOA) of the sound signal along with the location estimation in three-dimensional space to precisely locate a sound source. The experimental arrangement consists of four microphones and a single sound source. Previously, sound source has been localized using six or more microphones. The precision of sound localization has been demonstrated to increase with the use of more microphones. In this research, however, we minimized the use of microphones to reduce the complexity of the algorithm and the computation time as well. The method results in novelty in the field of sound source localization by using less resources and providing results that are at par with the more complex methods requiring more microphones and additional tools to locate the sound source. The average accuracy of the system is found to be 96.77% with an error factor of 3.8%.


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