The Effects of Target Spectrum, Noise, and Reverberation on Auditory Cue Weighting in Sound Localization PDF Download
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Author: Tran M. Nguyen
Publisher:
ISBN:
Category :
Languages : en
Pages : 314
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Book Description
Sound localization in the horizontal plane depends on interaural time difference (ITD) and interaural level difference (ILD) cues, which are both available in wideband sounds. Previous studies have directly measured listener weighting of those cues only under quiet, anechoic conditions, but not in the presence of noise and reverberation, which can degrade both ITD and ILD. This study examined the effects of changes in target spectral profile, background noise, and reverberation on sound localization performance and cue weighting strategies. Listeners reported locations of targets that were presented over headphones in virtual auditory space. ITD and ILD were manipulated by attenuating or delaying the sound at one ear, and their weighting was computed by comparing the listener's localization response bias to the imposed cue bias. Results suggest that ITD dominates for any wideband target in quiet conditions, but that listeners increase their weighting of ILD in more adverse listening conditions.
Author: Tran M. Nguyen
Publisher:
ISBN:
Category :
Languages : en
Pages : 314
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Book Description
Sound localization in the horizontal plane depends on interaural time difference (ITD) and interaural level difference (ILD) cues, which are both available in wideband sounds. Previous studies have directly measured listener weighting of those cues only under quiet, anechoic conditions, but not in the presence of noise and reverberation, which can degrade both ITD and ILD. This study examined the effects of changes in target spectral profile, background noise, and reverberation on sound localization performance and cue weighting strategies. Listeners reported locations of targets that were presented over headphones in virtual auditory space. ITD and ILD were manipulated by attenuating or delaying the sound at one ear, and their weighting was computed by comparing the listener's localization response bias to the imposed cue bias. Results suggest that ITD dominates for any wideband target in quiet conditions, but that listeners increase their weighting of ILD in more adverse listening conditions.
Author: Ewan A. Macpherson
Publisher:
ISBN:
Category :
Languages : en
Pages : 322
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Book Description
Author: Renita Elizabeth Sudirga
Publisher:
ISBN:
Category :
Languages : en
Pages : 314
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Book Description
Previous studies provide evidence that listening experience in a particular reverberant environment improves speech intelligibility and localization performance in that environment. Such studies, however, are few, and there is little knowledge of the underlying mechanisms. The experiments presented in this thesis explored the effect of reverberation context, in particular, the similarity in interaural coherence within a context, on listeners' performance in sound localization, speech perception in a spatially separated noise, spatial release from speech-on-speech masking, and target location identification in a multi-talker configuration. All experiments were conducted in simulated reverberant environments created with a loudspeaker array in an anechoic chamber. The reflections comprising the reverberation in each environment had the same temporal and relative amplitude patterns, but varied in their lateral spread, which affected the interaural coherence of reverberated stimuli. The effect of reverberation context was examined by comparing performance in two reverberation contexts, mixed and fixed. In the mixed context, the reverberation environment applied to each stimulus varied trial-by-trial, whereas in the fixed context, the reverberation environment was held constant within a block of trials. In Experiment I (absolute judgement of sound location), variability in azimuth judgments was lower in the fixed than in the mixed context, suggesting that sound localization depended not only on the cues presented in isolated trials. In Experiment II, the intelligibility of speech in a spatially separated noise was found to be similar in both reverberation contexts. That result contrasts with other studies, and suggests that the fixed context did not assist listeners in compensating for degraded interaural coherence. In Experiment III, speech intelligibility in multi-talker configurations was found to be better in the fixed context, but only when the talkers were separated. That is, the fixed context improved spatial release from masking. However, in the presence of speech maskers, consistent reverberation did not improve the localizability of the target talker in a three-alternative location-identification task. Those results suggest that in multi-talker situations, consistent coherence may not improve target localizability, but rather that consistent context may facilitate the buildup of spatial selective attention.
Author: Paul W. Anderson
Publisher:
ISBN:
Category : Auditory perception
Languages : en
Pages : 122
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Book Description
Auditory localization involves different cues depending on the spatial domain. Azimuth localization cues include interaural time differences (ITDs), interaural level differences (ILDs) and pinnae cues. Auditory distance perception (ADP) cues include intensity, spectral cues, binaural cues, and the direct-to-reverberant energy ratio (D/R). While D/R has been established as a primary ADP cue, it is unlikely that it is directly encoded in the auditory system because it can be difficult to extract from ongoing signals. It is also noteworthy that no neuronal population has been identified that specifically codes D/R. It has therefore been proposed that D/R is indirectly encoded in the auditory system, through sensitivity to other acoustic parameters that are correlated with D/R, such as temporal cues (Zahorik, 2002b), spectral properties (Jetzt, 1979; Larsen, 2008), and interaural correlation (Bronkhorst and Houtgast, 1999). An additional D/R correlate relies on attenuation of amplitude modulation (AM) as a function of distance. Room modulation transfer functions act as low-pass filters on AM signals, and therefore the direct portion of a signal will have less modulation depth attenuation than the reverberant portion. Although recent neural and behavioral work has demonstrated that this cue can provide distance information monaurally, the extent to which the modulation attenuation cue contributes to ADP relative to other ADP cues is not fully understood. It is also possible modulation attenuation by the room can provide additional directional localization information, perhaps through the resulting dynamic fluctuation of the ILD cue. The role of AM in directional sound localization has not been extensively studied, particularly in reverberant soundfields which can affect the modulation reaching the two ears in a directionally-dependent fashion. Three human psychophysical experiments assessed the role of AM signals in distance and directional auditory localization in reverberant soundfields. Experiment I focused on validating a graphical response method to be used in subsequent experiments. In Experiment II, an auditory distance estimation task was performed which yielded measures of the relative perceptual contributions of the modulation depth cue during ADP in a reverberant room. Experiment III investigated the effect of AM on binaural localization in the horizontal plane in a reverberant room.
Author: Deliang Wang
Publisher: Wiley-IEEE Press
ISBN:
Category : Medical
Languages : en
Pages : 432
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Book Description
Provides a comprehensive and coherent account of the state of the art in CASA, in terms of the underlying principles, the algorithms and system architectures that are employed, and the potential applications of this exciting new technology.
Author: Pawel Strumillo
Publisher: IntechOpen
ISBN: 9789533072241
Category : Technology & Engineering
Languages : en
Pages : 606
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Book Description
Sound source localization is an important research field that has attracted researchers' efforts from many technical and biomedical sciences. Sound source localization (SSL) is defined as the determination of the direction from a receiver, but also includes the distance from it. Because of the wave nature of sound propagation, phenomena such as refraction, diffraction, diffusion, reflection, reverberation and interference occur. The wide spectrum of sound frequencies that range from infrasounds through acoustic sounds to ultrasounds, also introduces difficulties, as different spectrum components have different penetration properties through the medium. Consequently, SSL is a complex computation problem and development of robust sound localization techniques calls for different approaches, including multisensor schemes, null-steering beamforming and time-difference arrival techniques. The book offers a rich source of valuable material on advances on SSL techniques and their applications that should appeal to researches representing diverse engineering and scientific disciplines.
Author: Ruth Y. Litovsky
Publisher: Springer Nature
ISBN: 3030571009
Category : Medical
Languages : en
Pages : 425
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Book Description
The field of Binaural Hearing involves studies of auditory perception, physiology, and modeling, including normal and abnormal aspects of the system. Binaural processes involved in both sound localization and speech unmasking have gained a broader interest and have received growing attention in the published literature. The field has undergone some significant changes. There is now a much richer understanding of the many aspects that comprising binaural processing, its role in development, and in success and limitations of hearing-aid and cochlear-implant users. The goal of this volume is to provide an up-to-date reference on the developments and novel ideas in the field of binaural hearing. The primary readership for the volume is expected to be academic specialists in the diverse fields that connect with psychoacoustics, neuroscience, engineering, psychology, audiology, and cochlear implants. This volume will serve as an important resource by way of introduction to the field, in particular for graduate students, postdoctoral scholars, the faculty who train them and clinicians.
Author: John F. Woodruff
Publisher:
ISBN:
Category :
Languages : en
Pages : 204
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Book Description
We also consider how the computational goal of CASA-based segregation should be defined in reverberant environments. The ideal binary mask (IBM) has been established as a main goal of CASA. While the IBM is defined unambiguously in anechoic conditions, in reverberant environments there is some flexibility in how one might define the target signal itself and therefore, ambiguity is introduced to the notion of the IBM. Due to the perceptual distinction between early and late reflections, we introduce the reflection boundary as a parameter to the IBM definition to allow target reflections to be divided into desirable and undesirable components. We conduct a series of intelligibility tests with normal hearing listeners to compare alternative IBM definitions. Results show that it is vital for the IBM definition to account for the energetic effect of early target reflections, and that late target reflections should be characterized as noise.
Author: Anna C. Diedesch
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 118
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Book Description
Author: Sasha Devore
Publisher:
ISBN:
Category :
Languages : en
Pages : 176
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Book Description
Nearly all listening environments-indoors and outdoors alike-are full of boundary surfaces (e.g., walls, trees, and rocks) that produce acoustic reflections. These reflections interfere with the direct sound arriving at a listener's ears, distorting the binaural cues for sound localization. Yet, human listeners have little difficulty localizing sounds in most settings. This thesis addresses fundamental questions regarding the neural basis of sound localization in everyday reverberant environments. In the first set of experiments, we investigate the effects of reverberation on the directional sensitivity of low-frequency auditory neurons sensitive to interaural time differences (ITD), the principal cue for localizing sound containing low frequency energy. Because reverberant energy builds up over time, the source location is represented relatively faithfully during the early portion of a sound, but this representation becomes increasingly degraded later in the stimulus. We show that the directional sensitivity of ITD-sensitive neurons in the auditory midbrain of anesthetized cats and awake rabbits follows a similar time course. However, the tendency of neurons to fire preferentially at the onset of a stimulus results in more robust directional sensitivity than expected, suggesting a simple mechanism for improving directional sensitivity in reverberation. To probe the role of temporal response dynamics, we use a conditioning paradigm to systematically alter temporal response patterns of single neurons. Results suggest that making temporal response patterns less onset-dominated typically leads to poorer directional sensitivity in reverberation. In parallel behavioral experiments, we show that human lateralization judgments are consistent with predictions from a population rate model for decoding the observed midbrain responses, suggesting a subcortical origin for robust sound localization in reverberant environments. In the second part of the thesis we examine the effects of reverberation on directional sensitivity of neurons across the tonotopic axis in the awake rabbit auditory midbrain. We find that reverberation degrades the directional sensitivity of single neurons, although the amount of degradation depends on the characteristic frequency and the type of binaural cues available. When ITD is the only available directional cue, low frequency neurons sensitive to ITD in the fine-time structure maintain better directional sensitivity in reverberation than high frequency neurons sensitive to ITD in the envelope. On the other hand, when both ITD and interaural level differences (ILD) cues are available, directional sensitivity is comparable throughout the tonotopic axis, suggesting that, at high frequencies, ILDs provide better directional information than envelope ITDs in reverberation. These findings can account for results from human psychophysical studies of spatial hearing in reverberant environments. This thesis marks fundamental progress towards elucidating the neural basis for spatial hearing in everyday settings. Overall, our results suggest that the information contained in the rate responses of neurons in the auditory midbrain is sufficient to account for human sound localization in reverberant environments.
