Auditory Spatial Perception Research Articles

Highly compromised auditory spatial perception in aided congenitally hearing-impaired and rapid improvement with tactile technology

Spatial understanding is a multisensory construct while hearing is the only natural sense enabling the simultaneous perception of the entire 3D space. To test whether such spatial understanding is dependent on auditory experience, we study congenitally hearing-impaired users of assistive devices. We apply an in-house technology, which, inspired by the auditory system, performs intensity-weighting to represent external spatial positions and motion on the fingertips. We see highly impaired auditory spatial capabilities for tracking moving sources, which based on the "critical periods" theory emphasizes the role of nature in sensory development. Meanwhile, for tactile and audio-tactile spatial motion perception, the hearing-impaired show performance similar to typically hearing individuals. The immediate availability of 360° external space representation through touch, despite the lack of such experience during the lifetime, points to the significant role of nurture in spatial perception development, and to its amodal character. The findings show promise toward advancing multisensory solutions for rehabilitation.

Auditory Spatial Perception as a Function of Recreational Noise Exposure in Gen-Z Adults with Normal Hearing.

The study aimed to evaluate auditory spatial perception in individuals with and without recreational noise exposure using Virtual Acoustic Space Identification. A standard group comparison design using purposive sampling was conducted on 60 normal-hearing participants aged 18-30. They were divided into experimental and control groups based on their scores on the recreational hearing habits questionnaire (CHAR). The experimental group was exposed to recreational noise for at least 4h per day, while the control group had no noise exposure. The procedure involved the administration of Virtual Acoustic Space Identification (VASI) at 65 dB SPL. Spatial perception was measured at eight spatial percepts within the head. Based on the confusion matrix, accuracy scores, reaction time at each virtual location, and the overall VASI score were calculated. The results indicate a significant difference in Front errors and Front-as-back errors in the two groups; people with recreational noise exposure had more errors in these spatial percepts. This indicates the differential impact of recreational noise on auditory spatial perception. The differences observed in the test can be attributed to the complexity of the auditory spatial perception task, the stimulus and the better sensitivity of the VASI in detecting spatial deficits. Recreational noise exposure affects spatial auditory perception, emphasizing the importance of mitigating recreational noise-related risks for auditory spatial skills.

Effects of measured and simulated diffraction from a plate on sound source localization.

In daily life, natural or man-made structures influence sound propagation, causing reflections and diffraction with potential effects on auditory spatial perception. While the effect of isolated reflections on binaural localization has been investigated, consequences of edge diffraction on spatial perception have received less attention. Here, effects of edge diffraction on the horizontal localization of a sound source were assessed when a flat square plate occludes the direct sound or produces a reflection in an otherwise anechoic environment. Binaural recordings were obtained with an artificial head for discrete sound source positions along two horizontal trajectories in the vicinity of the plate, including conditions near the incident and reflection shadow boundary. In a listening test, the apparent source position was matched for conditions with and without the plate, resulting in azimuth offsets between the apparent and physical source of up to 12°. The perceived direction of occluded frontal sound sources was laterally shifted to the visible region near the edge of the plate. Geometrical-acoustics-based simulations with different methods to binaurally render diffracted sound paths were technically and perceptually compared to the measurements. The observed localization offset was reproduced with the acoustic simulations when diffraction was rendered considering the individual ear positions.

Body representation drives auditory spatial perception

In contrast to the large body of findings confirming the influence of auditory cues on body perception and movement-related activity, the influence of body representation on spatial hearing remains essentially unexplored. Here, we use a disorientation task to assess whether a change in the body's orientation in space could lead to an illusory shift in the localization of a sound source. While most of the participants were initially able to locate the sound source with great precision, they all made substantial errors in judging the position of the same sound source following the body orientation-altering task. These results demonstrate that a change in body orientation can have a significant impact on the auditory processes underlying sound localization. The illusory errors not only confirm the strong connection between the auditory system and the representation of the body in space but also raise questions about the importance of hearing in determining spatial position.

Exploring the limits of virtual source localization with amplitude panning on a flat panel with actuator array: Implications for future researcha).

Immersive and spatial sound reproduction has been widely studied using loudspeaker arrays. However, flat-panel loudspeakers that utilize thin flat panels with force actuators are a promising alternative to traditional coaxial loudspeakers for practical applications, with benefits in low-visual profiles and diffuse radiation. Literature has addressed the sound quality and applications of flat-panel loudspeakers in three-dimensional sound reproduction, such as wave field synthesis and sound zones. This paper revisits the spatial sound perception of flat-panel loudspeakers, specifically the localization mismatch between the perceived and desired sound directions when using amplitude panning. Subjective tests in an anechoic chamber with 24 subjects result in the mean azimuth direction mismatch within ±6.0° and the mean elevation mismatch within ±10.0°. The experimental results show that the virtual source created by amplitude panning over a flat-panel loudspeaker still achieves spatial localization accuracy close to that of a real sound source, despite not using complex algorithms or acoustic transfer function information. The findings of this study establish a benchmark for virtual source localization in spatial sound reproduction using flat-panel loudspeakers, which can serve as a starting point for future research and optimization of algorithms.

Closed-field Auditory Spatial Perception and Its Relationship to Musical Aptitude

Introduction: Musical aptitude is the innate ability of an individual to understand, appreciate, improvise, and have a good sense of pitch and rhythm, even without undergoing formal musical training. The present study aimed to understand the effect of musical aptitude on auditory spatial perception. Method: Forty nonmusicians were subjected to a musical aptitude test Mini Profile of Music Perception Skills (Mini-PROMS) based on which they were divided into two groups. Group I included 20 nonmusicians with good musical aptitude (NM-GA) and Group II comprised 20 nonmusicians with poor musical aptitude (NM-PA). Auditory spatial tests included interaural time difference (ITD) and interaural level difference (ILD) threshold tests and a closed-field spatial test called virtual acoustic space identification (VASI) test. Results: Kruskal–Wallis test revealed a significant difference between Group I (NM-GA) and Group II (NM-PA) in ITD (p < 0.001), ILD (p = 0.002), and VASI (p = 0.012) tests, suggesting the role of musical aptitude in auditory spatial perception. Correlational analyses showed a moderate positive correlation between Mini-PROMS scores with VASI (r = 0.31, p = 0.04) and a moderate negative correlation with ILD (r = −0.3, p = 0.04) and ITD (r = −0.5, p = 0.001). Conclusion: This study defines a positive association between musical aptitude and auditory spatial perception. Further research should include a comparison of spatial skills among musicians and nonmusicians with good musical aptitude.

"Rear bias" in spatial auditory perception: Attentional and affective vigilance to sounds occurring outside the visual field.

Presented studies explored the rear bias phenomenon, that is, the attentional and affective bias to sounds occurring behind the listener. Physiological and psychological reactions (i.e., fEMG, EDA/SCR, Simple Reaction Task-SRT, and self-assessments of affect-related states) were measured in response to tones of different frequencies (Study 1) and emotional vocalizations (Study 2) presented in rear and front spatial locations. Results showed that emotional vocalizations, when located in the back, facilitate reactions related to attention orientation (i.e., auricularis muscle response and simple reaction times) and evoke higher arousal-both physiological (as measured by SCR) and psychological (self-assessment scale). Importantly, observed asymmetries were larger for negative and threat-related signals (e.g., anger) than positive/nonthreatening ones (e.g., achievement). By contrast, there were only small differences for the relatively higher frequency tones. The observed relationships are discussed in terms of one of the postulated auditory system's functions, which is monitoring of the environment in order to quickly detect potential threats that occur outside of the visual field (e.g., behind one's back).

Feasibility of Virtual Reality-Based Auditory Localization Training With Binaurally Recorded Auditory Stimuli for Patients With Single-Sided Deafness.

To train participants to localize sound using virtual reality (VR) technology, appropriate auditory stimuli that contain accurate spatial cues are essential. The generic head-related transfer function that grounds the programmed spatial audio in VR does not reflect individual variation in monaural spatial cues, which is critical for auditory spatial perception in patients with single-sided deafness (SSD). As binaural difference cues are unavailable, auditory spatial perception is a typical problem in the SSD population and warrants intervention. This study assessed the applicability of binaurally recorded auditory stimuli in VR-based training for sound localization in SSD patients. Sixteen subjects with SSD and 38 normal-hearing (NH) controls underwent VR-based training for sound localization and were assessed 3 weeks after completing training. The VR program incorporated prerecorded auditory stimuli created individually in the SSD group and over an anthropometric model in the NH group. Sound localization performance revealed significant improvements in both groups after training, with retained benefits lasting for an additional 3 weeks. Subjective improvements in spatial hearing were confirmed in the SSD group. By examining individuals with SSD and NH, VR-based training for sound localization that used binaurally recorded stimuli, measured individually, was found to be effective and beneficial. Furthermore, VR-based training does not require sophisticated instruments or setups. These. suggest that this technique represents a new therapeutic treatment for impaired sound localization.

An Effect of Gaze Direction in Cocktail Party Listening.

It is well established that gaze direction can influence auditory spatial perception, but the implications of this interaction for performance in complex listening tasks is unclear. In the current study, we investigated whether there is a measurable effect of gaze direction on speech intelligibility in a "cocktail party" listening situation. We presented sequences of digits from five loudspeakers positioned at 0°, ± 15°, and ± 30° azimuth, and asked participants to repeat back the digits presented from a designated target loudspeaker. In different blocks of trials, the participant visually fixated on a cue presented at the target location or at a nontarget location. Eye position was tracked continuously to monitor compliance. Performance was best when fixation was on-target (vs. off-target) and the size of this effect depended on the specific configuration. This result demonstrates an influence of gaze direction in multitalker mixtures, even in the absence of visual speech information.

Towards Maximizing a Perceptual Sweet Spot for Spatial Sound With Loudspeakers

The <i>sweet spot</i> can be interpreted as the region where acoustic sources create a spatial auditory illusion. We study the problem of maximizing this sweet spot when reproducing a desired sound wave using an array of loudspeakers. To achieve this, we introduce a theoretical framework for spatial sound perception that can be used to define a sweet spot, and we develop a method that aims to generate a sound wave that directly maximizes the sweet spot defined by a model within this framework. Our method aims to incorporate perceptual principles from the onset and it is flexible: it imposes little to no constraints on the regions of interest, the arrangement of loudspeakers or their radiation pattern. However, the perceptual models must satisfy a convexity condition, which is fulfilled by state-of-the-art monaural perceptual models, but not by binaural ones. Proof-of-concept experiments show that our method, when implemented with van de Par&#x0027;s monaural model, outperforms state-of-the-art sound field synthesis methods in terms of their binaural azimuth localization and binaural coloration properties.

Age and Auditory Spatial Perception in Humans: Review of Behavioral Findings and Suggestions for Future Research.

It has been well documented, and fairly well known, that concomitant with an increase in chronological age is a corresponding increase in sensory impairment. As most people realize, our hearing suffers as we get older; hence, the increased need for hearing aids. The first portion of the present paper is how the change in age apparently affects auditory judgments of sound source position. A summary of the literature evaluating the changes in the perception of sound source location and the perception of sound source motion as a function of chronological age is presented. The review is limited to empirical studies with behavioral findings involving humans. It is the view of the author that we have an immensely limited understanding of how chronological age affects perception of space when based on sound. In the latter part of the paper, discussion is given to how auditory spatial perception is traditionally conducted in the laboratory. Theoretically, beneficial reasons exist for conducting research in the manner it has been. Nonetheless, from an ecological perspective, the vast majority of previous research can be considered unnatural and greatly lacking in ecological validity. Suggestions for an alternative and more ecologically valid approach to the investigation of auditory spatial perception are proposed. It is believed an ecological approach to auditory spatial perception will enhance our understanding of the extent to which individuals perceive sound source location and how those perceptual judgments change with an increase in chronological age.

Effects of Stimulation Position and Frequency Band on Auditory Spatial Perception with Bilateral Bone Conduction.

Virtual sound localization tests were conducted to examine the effects of stimulation position (mastoid, condyle, supra-auricular, temple, and bone-anchored hearing aid implant position) and frequency band (low frequency, high frequency, and broadband) on bone-conduction (BC) horizontal localization. Non-individualized head-related transfer functions were used to reproduce virtual sound through bilateral BC transducers. Subjective experiments showed that stimulation at the mastoid gave the best performance while the temple gave the worst performance in localization. Stimulation at the mastoid and condyle did not differ significantly from that using air-conduction (AC) headphones in localization accuracy. However, binaural reproduction at all BC stimulation positions led to similar levels of front-back confusion (FBC), which were also comparable to that with AC headphones. Binaural BC reproduction with high-frequency stimulation led to significantly higher localization accuracy than with low-frequency stimulation. When transcranial attenuation (TA) was measured, the attenuation became larger at the condyle and mastoid, and increased at high frequencies. The experiments imply that larger TAs may improve localization accuracy but do not improve FBC. The present study indicates that the BC stimulation at the mastoid and condyle can effectively convey spatial information, especially with high-frequency stimulation.

Hybrid multi-harmonic model for the prediction of interaural time differences in individual behind-the-ear hearing-aid-related transfer functions

Spatial sound perception in aided listeners partly relies on hearing-aid-related transfer functions (HARTFs), describing the directional acoustic paths between a sound source and the hearing-aid (HA) microphones. Compared to head-related transfer functions (HRTFs), the HARTFs of behind-the-ear HAs exhibit substantial differences in spectro-temporal characteristics and binaural cues such as interaural time differences (ITDs). Since assumptions on antipodal microphone placement on the equator of a three-concentric sphere are violated in such datasets, predicting the ITDs via Kuhn’s simple analytic harmonic model entails excessive errors. Although angular ear-canal offsets have been addressed in an extended Woodworth model, the prediction errors remain large if the frequency range does not comply with the model specifications. Tuned to the previously inaccurately modelled frequency range between 500 Hz and 1.5 kHz, we propose a hybrid multi-harmonic model to predict the ITDs in HRTFs and HARTFs for arbitrary directions in the horizontal plane with superior accuracy. The target model coefficients are derived from individual directional measurements of 30 adults, wearing two dual-microphone behind-the-ear HAs and two in-ear microphones. Model individualisation is facilitated by the availability of polynomial weights that are applied to subsets of individual anthropometric and HA features to estimate the target model coefficients. The model is published as part of the Auditory Modeling Toolbox (AMT,pausch2022) and supplemented with the individual features and directional datasets.

Psychoacoustic Principle, Methods, and Problems with Perceived Distance Control in Spatial Audio

One purpose of spatial audio is to create perceived virtual sources at various spatial positions in terms of direction and distance with respect to the listener. The psychoacoustic principle of spatial auditory perception is essential for creating perceived virtual sources. Currently, the technical means for recreating virtual sources in different directions of various spatial audio techniques are relatively mature. However, perceived distance control in spatial audio remains a challenging task. This article reviews the psychoacoustic principle, methods, and problems with perceived distance control and compares them with the principles and methods of directional localization control in spatial audio, showing that the validation of various methods for perceived distance control depends on the principle and method used for spatial audio. To improve perceived distance control, further research on the detailed psychoacoustic mechanisms of auditory distance perception is required.

Unilateral Conductive Hearing Loss Disrupts the Developmental Refinement of Binaural Processing in the Rat Primary Auditory Cortex.

Binaural hearing is critically important for the perception of sound spatial locations. The primary auditory cortex (AI) has been demonstrated to be necessary for sound localization. However, after hearing onset, how the processing of binaural cues by AI neurons develops, and how the binaural processing of AI neurons is affected by reversible unilateral conductive hearing loss (RUCHL), are not fully elucidated. Here, we determined the binaural processing of AI neurons in four groups of rats: postnatal day (P) 14–18 rats, P19–30 rats, P57–70 adult rats, and RUCHL rats (P57–70) with RUCHL during P14–30. We recorded the responses of AI neurons to both monaural and binaural stimuli with variations in interaural level differences (ILDs) and average binaural levels. We found that the monaural response types, the binaural interaction types, and the distributions of the best ILDs of AI neurons in P14–18 rats are already adult-like. However, after hearing onset, there exist developmental refinements in the binaural processing of AI neurons, which are exhibited by the increase in the degree of binaural interaction, and the increase in the sensitivity and selectivity to ILDs. RUCHL during early hearing development affects monaural response types, decreases the degree of binaural interactions, and decreases both the selectivity and sensitivity to ILDs of AI neurons in adulthood. These new evidences help us to understand the refinements and plasticity in the binaural processing of AI neurons during hearing development, and might enhance our understanding in the neuronal mechanism of developmental changes in auditory spatial perception.

空间声原理及其相关的物理、听觉问题

<p indent="0mm">Spatial sound aims to record, transmit, and reproduce the spatial information of the sound field and recreate the desired spatial auditory events or perceptions. It is a frontier field in acoustics and has undergone rapid advancement recently. It has also been widely used in scientific research, engineering technology, and cultural entertainment. The physical analysis of the sound field and the spatial auditory perception mechanism are two foundations of spatial sound. Signal processing is a technical approach for implementing spatial sound. Therefore, spatial sound handles fundamental and technical problems of sound field, hearing, and practical implementation in the crossfield of acoustics (physics), auditory perceptions, and signal processing. The principle, development, key scientific and technical problems, progress, and representative applications of spatial sound are reviewed in this article. Moreover, the technical and application prospects of spatial sound are addressed.

Numbers in short-term memory bias auditory spatial perception.

The cognitive penetration literature suggests that top-down knowledge influences perception, but whether such influences exist is controversial. We tested for top-down influences on perception by loading short-term memory with digits and then had participants make perceptual judgments to index spatial hearing. Memory of spatial number codes were predicted to bias spatial judgments to the left for small digits and rightward for larger digits. Participants encoded one or more digits and then made spatial judgments in either spatial hearing or dichotic listening tasks. Results across five experiments supported the predicted spatial biases. Digits had to be deliberately encoded, and at least two were needed to be memorized before a small number left-right bias in dichotic listening was evident. In dichotic listening, smaller numbers in memory also promoted more intrusions, and a mix of small and large numbers enhanced the right ear advantage. Results suggest that long-term knowledge about number magnitude imparts a top-down bias on auditory spatial perception. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Creation of Auditory Augmented Reality Using a Position-Dynamic Binaural Synthesis System—Technical Components, Psychoacoustic Needs, and Perceptual Evaluation

For a spatial audio reproduction in the context of augmented reality, a position-dynamic binaural synthesis system can be used to synthesize the ear signals for a moving listener. The goal is the fusion of the auditory perception of the virtual audio objects with the real listening environment. Such a system has several components, each of which help to enable a plausible auditory simulation. For each possible position of the listener in the room, a set of binaural room impulse responses (BRIRs) congruent with the expected auditory environment is required to avoid room divergence effects. Adequate and efficient approaches are methods to synthesize new BRIRs using very few measurements of the listening room. The required spatial resolution of the BRIR positions can be estimated by spatial auditory perception thresholds. Retrieving and processing the tracking data of the listener’s head-pose and position as well as convolving BRIRs with an audio signal needs to be done in real-time. This contribution presents work done by the authors including several technical components of such a system in detail. It shows how the single components are affected by psychoacoustics. Furthermore, the paper also discusses the perceptive effect by means of listening tests demonstrating the appropriateness of the approaches.

Estimation of Spectral Notches From Pinna Meshes: Insights From a Simple Computational Model

While previous research on spatial sound perception investigated the physical mechanisms producing the most relevant elevation cues, how spectral notches are generated and related to the individual morphology of the human pinna is still a topic of debate. Correctly modeling these important elevation cues, and in particular the lowest frequency notches, is an essential step for individualizing Head-Related Transfer Functions (HRTFs). In this paper we propose a simple computational model able to predict the center frequencies of pinna notches from ear meshes. We apply such a model to a highly controlled HRTF dataset built with the specific purpose of understanding the contribution of the pinna to the HRTF. Results show that the computational model is able to approximate the lowest frequency notch with improved accuracy with respect to other state-of-the-art methods. By contrast, the model fails to predict higher-order pinna notches correctly. The proposed approximation supplements understanding of the morphology involved in generating spectral notches in experimental HRTFs.

Spatial Soundscapes and Virtual Worlds: Challenges and Opportunities.

There is increasing effort to characterize the soundscapes around us so that we can design more compelling and immersive experiences. This review paper focuses on the challenges and opportunities around sound perception, with a particular focus on spatial sound perception in a virtual reality (VR) cityscape. We review how research on temporal aspects has recently been extended to evaluating spatial factors when designing soundscapes. In particular, we discuss key findings on the human capability of localizing and distinguishing spatial sound cues for different technical setups. We highlight studies carried out in both real-world and virtual reality settings to evaluate spatial sound perception. We conclude this review by highlighting the opportunities offered by VR technology and the remaining open questions for virtual soundscape designers, especially with the advances in spatial sound stimulation.