ORCID Profile
0000-0001-6188-9761
Current Organisation
Macquarie University
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Publisher: Acoustical Society of America (ASA)
Date: 08-2015
DOI: 10.1121/1.4923449
Abstract: The relevance of informational masking (IM) in real-world listening is not well understood. In literature, IM effects of up to 10 dB in measured speech reception thresholds (SRTs) are reported. However, these experiments typically employed simplified spatial configurations and speech corpora that magnified confusions. In this study, SRTs were measured with normal hearing subjects in a simulated cafeteria environment. The environment was reproduced by a 41-channel 3D-loudspeaker array. The target talker was 2 m in front of the listener and masking talkers were either spread throughout the room or colocated with the target. Three types of maskers were realized: one with the same talker as the target (maximum IM), one with talkers different from the target, and one with unintelligible, noise-vocoded talkers (minimal IM). Overall, SRTs improved for the spatially distributed conditions compared to the colocated conditions. Within the spatially distributed conditions, there was no significant difference between thresholds with the different- and vocoded-talker maskers. Conditions with the same-talker masker were the only conditions with substantially higher thresholds, especially in the colocated conditions. These results suggest that IM related to target-masker confusions, at least for normal-hearing listeners, is of low relevance in real-life listening.
Publisher: Acoustical Society of America (ASA)
Date: 05-2013
DOI: 10.1121/1.4799007
Abstract: A binaural dereverberation algorithm is presented that utilizes the properties of the interaural coherence (IC) inspired by the concepts introduced in Allen et al. [J. Acoust. Soc. Am. 62, 912–915 (1977)]. The algorithm introduces a non-linear sigmoidal coherence-to-gain mapping that is controlled by an online estimate of the present coherence statistics. The algorithm automatically adapts to a given acoustic environment and provides a stronger dereverberation effect than the original method presented in Allen et al. [J. Acoust. Soc. Am. 62, 912–915 (1977)] in most acoustic conditions. The performance of the proposed algorithm was objectively and subjectively evaluated in terms of its impacts on the amount of reverberation and overall quality. A binaural spectral subtraction method based on Lebart et al. [Acta Acust. Acust. 87, 359–366 (2001)] and a binaural version of the original method of Allen et al. were considered as reference systems. The results revealed that the proposed coherence-based approach is most successful in acoustic scenarios that exhibit a significant spread in the coherence distribution where direct sound and reverberation can be segregated. This dereverberation algorithm is thus particularly useful in large rooms for short source-receiver distances.
Publisher: Georg Thieme Verlag KG
Date: 07-2016
DOI: 10.3766/JAAA.15089
Abstract: Background: Many listeners with hearing loss report particular difficulties with multitalker communication situations, but these difficulties are not well predicted using current clinical and laboratory assessment tools. Purpose: The overall aim of this work is to create new speech tests that capture key aspects of multitalker communication situations and ultimately provide better predictions of real-world communication abilities and the effect of hearing aids. Research Design: A test of ongoing speech comprehension introduced previously was extended to include naturalistic conversations between multiple talkers as targets, and a reverberant background environment containing competing conversations. In this article, we describe the development of this test and present a validation study. Study S le: Thirty listeners with normal hearing participated in this study. Data Collection and Analysis: Speech comprehension was measured for one-, two-, and three-talker passages at three different signal-to-noise ratios (SNRs), and working memory ability was measured using the reading span test. Analyses were conducted to examine passage equivalence, learning effects, and test–retest reliability, and to characterize the effects of number of talkers and SNR. Results: Although we observed differences in difficulty across passages, it was possible to group the passages into four equivalent sets. Using this grouping, we achieved good test–retest reliability and observed no significant learning effects. Comprehension performance was sensitive to the SNR but did not decrease as the number of talkers increased. In idual performance showed associations with age and reading span score. Conclusions: This new dynamic speech comprehension test appears to be valid and suitable for experimental purposes. Further work will explore its utility as a tool for predicting real-world communication ability and hearing aid benefit.
Publisher: Springer Berlin Heidelberg
Date: 2013
Publisher: Elsevier BV
Date: 05-2006
Publisher: ASA
Date: 2013
DOI: 10.1121/1.4799721
Publisher: Wissenschaftliche Verlagsgesellschaft mbH
Date: 05-2013
DOI: 10.3813/AAA.918628
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2010
Publisher: Acoustical Society of America (ASA)
Date: 11-2005
DOI: 10.1121/1.2074907
Abstract: The concept of flat-walled multilayered absorbent linings for anechoic rooms was proposed three decades ago. Flat-walled linings have the advantage of being less complicated and, hence, less costly to manufacture and install than the in idual units such as wedges. However, there are difficulties in optimizing the design of such absorbent linings. In the present work, the design of a flat-walled multilayered anechoic lining that targeted a 250 Hz cut-off frequency and a 300 mm maximum lining thickness was first optimized using an evolutionary algorithm. Sixteen of the most commonly used commercial fibrous building insulation materials available in Australia were investigated and fourteen design options (i.e., material combinations) were found by the evolutionary algorithm. These options were then evaluated in accordance with their costs and measured acoustic absorption performances. Finally, the completed anechoic room, where the optimized design was applied, was qualified and the results showed that a large percentage (75%–85%) of the distance between the sound source and the room boundaries, on the traverses made, were anechoic.
Publisher: Acoustical Society of America (ASA)
Date: 03-2017
DOI: 10.1121/1.4979000
Abstract: The extent to which informational masking (IM) is involved in real-world listening is not well understood. In the literature, IM effects of more than 8 dB are reported, but these experiments typically used simplified spatial configurations and speech materials with exaggerated confusions. Westermann and Buchholz [(2015b). J. Acoust. Soc. Am. 138, 584–593] considered a simulated cafeteria and found only substantial IM effects when the target and maskers were colocated and the same talker. The present study further investigates the relevance of IM in real-world environments, specifically distractions by nearby maskers and the effect of hearing impairment. Speech reception thresholds (SRTs) were measured with normal hearing (NH) and sensorineural hearing impaired (HI) listeners in a simulated cafeteria environment. Three different masker configurations were considered: (1) seven dialogues distributed in the cafeteria, (2) two monologues presented close to the listener with varying angular separation, and (3) a combination of (1) and (2). The contribution of IM was measured as the difference in SRTs between speech maskers and unintelligible vocoded maskers. No significant IM was found with the seven dialogues alone. Including nearby maskers resulted in substantial IM for both NH and HI listeners, suggesting that such maskers might result in IM in real-world environments.
Publisher: Acoustical Society of America (ASA)
Date: 08-2016
DOI: 10.1121/1.4961006
Abstract: Better-ear glimpsing is an auditory process that takes advantage of short-term interaural level differences (ILDs) to improve the understanding of speech in spatial fluctuating noise. Since ILDs are mainly present at high frequencies, where most hearing-impaired (HI) listeners have the strongest hearing loss, HI in iduals cannot fully utilize ILDs for better-ear glimpsing, which may lead to poorer understanding of speech in noise. This problem may be alleviated by hearing aids that artificially generate ILDs at low frequencies where hearing is typically less impaired. The present study therefore investigated the spatial benefit in speech intelligibility that is provided by better-ear glimpsing with low-frequency extended ILDs in a symmetric two-distractor speech background. Speech reception thresholds were measured in a spatially co-located and separated condition as a function of frequency region in ten normal-hearing (NH) and ten mild-to-moderate sensorineural HI subjects. In both groups the extended ILDs provided a substantial spatial advantage on top of the advantage already provided by natural ILDs. Moreover, the spatial advantage was largely independent of frequency region, suggesting that both NH and HI subjects can utilize low-frequency ILDs for improving speech understanding in noise. Overall performance as well as spatial advantage was reduced in the HI group.
Publisher: American Speech Language Hearing Association
Date: 08-2015
DOI: 10.1044/2015_JSLHR-H-14-0332
Abstract: Open-plan classroom styles are increasingly being adopted in Australia despite evidence that their high intrusive noise levels adversely affect learning. The aim of this study was to develop a new Australian speech perception task (the Mealings, Demuth, Dillon, and Buchholz Classroom Speech Perception Test) and use it in an open-plan classroom to assess how intrusive noise affects speech perception. The first part of this article describes how the online 4-picture choice speech perception task materials were created. The second part focuses on the study involving twenty-two 5- to 6-year-old children in an open-plan classroom who completed the task while other classes engaged in quiet and noisy activities. Children's performance accuracy, number of responses, and speed were lower in the noisy condition compared with the quiet condition. In addition, children's speech perception scores decreased the farther away they were seated from the loudspeaker. Overall, the children understood and were engaged in the task, demonstrating that it is an appropriate tool for assessing speech perception live in the classroom with 5- to 6-year-old children. The results suggest that the Mealings, Demuth, Dillon, and Buchholz Classroom Speech Perception Test is a helpful tool for assessing speech perception in classrooms and that it would be beneficial to use in future research investigating how classroom design and noise affect speech perception.
Publisher: Wissenschaftliche Verlagsgesellschaft mbH
Date: 09-2018
DOI: 10.3813/AAA.919243
Publisher: SAGE Publications
Date: 28-07-2017
Publisher: Acoustical Society of America (ASA)
Date: 02-2015
DOI: 10.1121/1.4906581
Abstract: The influence of spatial separation in source distance on speech reception thresholds (SRTs) is investigated. In one scenario, the target was presented at 0.5 m distance, and the masker varied from 0.5 m distance up to 10 m. In a second scenario, the masker was presented at 0.5 m distance and the target distance varied. The stimuli were synthesized using convolution with binaural room impulse responses (BRIRs) measured on a dummy head in a reverberant auditorium, and were equalized to compensate for distance-dependent spectral and intensity changes. All sources were simulated directly in front of the listener. SRTs decreased monotonically when the target was at 0.5 m and the speech-masker was moved further away, resulting in a SRT improvement of up to 10 dB. When the speech masker was at 0.5 m and the target was moved away, a large variation across subjects was observed. Neither short-term signal-to-noise ratio (SNR) improvements nor cross-ear glimpsing could account for the observed improvement in intelligibility. However, the effect might be explained by an improvement in the SNR in the modulation domain and a decrease in informational masking. This study demonstrates that distance-related cues can play a significant role when listening in complex environments.
Publisher: Acoustical Society of America (ASA)
Date: 08-2013
DOI: 10.1121/1.4812264
Abstract: Real-world sound sources are usually perceived as externalized and thus properly localized in both direction and distance. This is largely due to (1) the acoustic filtering by the head, torso, and pinna, resulting in modifications of the signal spectrum and thereby a frequency-dependent shaping of interaural cues and (2) interaural cues provided by the reverberation inside an enclosed space. This study first investigated the effect of room reverberation on the spectro-temporal behavior of interaural level differences (ILDs) by analyzing dummy-head recordings of speech played at different distances in a standard listening room. Next, the effect of ILD fluctuations on the degree of externalization was investigated in a psychoacoustic experiment performed in the same listening room. In idual binaural impulse responses were used to simulate a distant sound source delivered via headphones. The ILDs were altered using a gammatone filterbank for analysis and resynthesis, where the envelopes of the left and right-ear signals were modified such that the naturally occurring fluctuations of the ILDs were restricted. This manipulation reduced the perceived degree of externalization. This was consistent with the analysis of short-term ILDs at different distances showing that a decreased distance to the sound source also reduced the ILD fluctuations.
Publisher: Acoustical Society of America (ASA)
Date: 02-2016
DOI: 10.1121/1.4941567
Abstract: It has been shown that intelligibility can be improved for cochlear implant (CI) recipients with the ideal binary mask (IBM). In realistic scenarios where prior information is unavailable, however, the IBM must be estimated, and these estimations will inevitably contain errors. Although the effects of both unstructured and structured binary mask errors have been investigated with normal-hearing (NH) listeners, they have not been investigated with CI recipients. This study assesses these effects with CI recipients using masks that have been generated systematically with a statistical model. The results demonstrate that clustering of mask errors substantially decreases the tolerance of errors, that incorrectly removing target-dominated regions can be as detrimental to intelligibility as incorrectly adding interferer-dominated regions, and that the in idual tolerances of the different types of errors can change when both are present. These trends follow those of NH listeners. However, analysis with a mixed effects model suggests that CI recipients tend to be less tolerant than NH listeners to mask errors in most conditions, at least with respect to the testing methods in each of the studies. This study clearly demonstrates that structure influences the tolerance of errors and therefore should be considered when analyzing binary-masking algorithms.
Publisher: IEEE
Date: 09-2014
Publisher: Acoustical Society of America (ASA)
Date: 06-2015
DOI: 10.1121/1.4919330
Abstract: Recently, an increased interest has been demonstrated in evaluating hearing aids (HAs) inside controlled, but at the same time, realistic sound environments. A promising candidate that employs loudspeakers for realizing such sound environments is the listener-centered method of higher-order ambisonics (HOA). Although the accuracy of HOA has been widely studied, it remains unclear to what extent the results can be generalized when (1) a listener wearing HAs that may feature multi-microphone directional algorithms is considered inside the reconstructed sound field and (2) reverberant scenes are recorded and reconstructed. For the purpose of objectively validating HOA for listening tests involving HAs, a framework was developed to simulate the entire path of sounds presented in a modeled room, recorded by a HOA microphone array, decoded to a loudspeaker array, and finally received at the ears and HA microphones of a dummy listener fitted with HAs. Reproduction errors at the ear signals and at the output of a cardioid HA microphone were analyzed for different anechoic and reverberant scenes. It was found that the diffuse reverberation reduces the considered time-averaged HOA reconstruction errors which, depending on the considered application, suggests that reverberation can increase the usable frequency range of a HOA system.
Publisher: Acoustical Society of America (ASA)
Date: 12-2018
DOI: 10.1121/1.5083823
Abstract: Better-ear glimpsing (BEG) utilizes interaural level differences (ILDs) to improve speech intelligibility in noise. This spatial benefit is reduced in most hearing-impaired (HI) listeners due to their increased hearing loss at high frequencies. Even though this benefit can be improved by providing increased lification, the improvement is limited by loudness discomfort. An alternative solution therefore extends ILDs to low frequencies, which has been shown to provide a substantial benefit from BEG. In contrast to previous studies, which only applied linear stimulus manipulations, wide dynamic range compression was applied here to improve the audibility of soft sounds while ensuring loudness comfort for loud sounds. Performance in both speech intelligibility and BEG was measured in 13 HI listeners at three different masker levels and for different interaural stimulus manipulations. The results revealed that at low signal levels, performance substantially improved with increasing masker level, but this improvement was reduced by the compressive behaviour at higher levels. Moreover, artificially extending ILDs by applying infinite (broadband) ILDs provided an extra spatial benefit in speech reception thresholds of up to 5 dB on top of that already provided by natural ILDs and interaural time differences, which increased with increasing signal level.
Publisher: Springer Science and Business Media LLC
Date: 2010
DOI: 10.1155/2010/840294
Publisher: Elsevier BV
Date: 12-2015
Publisher: Acoustical Society of America (ASA)
Date: 10-2018
DOI: 10.1121/1.5058776
Abstract: The auditory processes involved in the localization of sounds in rooms are still poorly understood. The present study investigated the auditory system's across-frequency processing of interaural time differences (ITDs) and the impact of the interaural coherence (IC) of the stimuli in ITD discrimination and localization. First, ITD discrimination thresholds were measured as a function of signal frequency, reference ITD, and IC using critical-band wide noises. The resulting data were fitted with a set of analytical functions and ITD weights were derived using concepts from signal detection theory. Inspired by the weighted-image model [Stern, Zeiberg, and Trahiotis. (1988). J. Acoust. Soc. Am. 84, 156–165], the derived ITD weights were then integrated in a simplified localization model using an optimal combination of ITD information across frequency. To verify this model, a series of localization experiments were conducted using broadband noise in which ITD and IC were varied across frequency. The model predictions were in good agreement with the experimental data, supporting the assumption that the auditory system performs a weighted integration of ITD information across frequency to localize a sound source. The results could be valuable for the design of new paradigms to measure localization in more complex acoustic conditions and may provide constraints for future localization models.
Publisher: Wissenschaftliche Verlagsgesellschaft mbH
Date: 03-2010
DOI: 10.3813/AAA.918285
Publisher: ASA
Date: 2013
DOI: 10.1121/1.4799593
Publisher: IEEE
Date: 2005
Publisher: SAGE Publications
Date: 2019
Abstract: The concept of complex acoustic environments has appeared in several unrelated research areas within acoustics in different variations. Based on a review of the usage and evolution of this concept in the literature, a relevant framework was developed, which includes nine broad characteristics that are thought to drive the complexity of acoustic scenes. The framework was then used to study the most relevant characteristics for stimuli of realistic, everyday, acoustic scenes: multiple sources, source ersity, reverberation, and the listener’s task. The effect of these characteristics on perceived scene complexity was then evaluated in an exploratory study that reproduced the same stimuli with a three-dimensional loudspeaker array inside an anechoic chamber. Sixty-five subjects listened to the scenes and for each one had to rate 29 attributes, including complexity, both with and without target speech in the scenes. The data were analyzed using three-way principal component analysis with a (2 3 2) Tucker3 model in the dimensions of scales (or ratings), scenes, and subjects, explaining 42% of variation in the data. “Comfort” and “variability” were the dominant scale components, which span the perceived complexity. Interaction effects were observed, including the additional task of attending to target speech that shifted the complexity rating closer to the comfort scale. Also, speech contained in the background scenes introduced a second subject component, which suggests that some subjects are more distracted than others by background speech when listening to target speech. The results are interpreted in light of the proposed framework.
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.HEARES.2011.01.002
Abstract: Coloration detection thresholds (CDTs) were measured for a single reflection as a function of spectral content and reflection delay for diotic stimulus presentation. The direct sound was a 320-ms long burst of bandpass-filtered noise with varying lower and upper cut-off frequencies. The resulting threshold data revealed that: (1) sensitivity decreases with decreasing bandwidth and increasing reflection delay and (2) high-frequency components contribute less to detection than low-frequency components. The auditory processes that may be involved in coloration detection (CD) are discussed in terms of a spectrum-based auditory model, which is conceptually similar to the pattern-transformation model of pitch (Wightman, 1973). Hence, the model derives an auto-correlation function of the input stimulus by applying a frequency analysis to an auditory representation of the power spectrum. It was found that, to successfully describe the quantitative behavior of the CDT data, three important mechanisms need to be included: (1) auditory bandpass filters with a narrower bandwidth than classic Gammatone filters, the increase in spectral resolution was here linked to cochlear suppression, (2) a spectral contrast enhancement process that reflects neural inhibition mechanisms, and (3) integration of information across auditory frequency bands.
Publisher: Informa UK Limited
Date: 02-09-2015
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.HEARES.2007.06.008
Abstract: Reflection masked thresholds (RMTs) for the simple scenario of a test reflection masked by the direct sound (200 ms long broadband noise) were measured as a function of reflection delay for diotic and dichotic stimulus presentations. In order to discriminate between contributions to reflection masking from simultaneous versus forward masking, the simultaneous RMT was measured in addition to the traditional RMT. Simultaneous RM was realized by truncating the offset of the test reflection such that the test reflection and the direct sound had a common offset. By comparing the experimental results for the two RMTs, it is shown that forward masking effects only have a significant effect on reflection masking for delays above 7-10 ms. Moreover, binaural mechanisms were revealed which deteriorate auditory detection of test reflections for delays below 7-10 ms and enhance detection for larger delays. The monaural and binaural processes that may underlie reflection masking are discussed in terms of auditory-modelling concepts.
Publisher: Elsevier BV
Date: 06-2018
Publisher: ASA
Date: 2013
DOI: 10.1121/1.4799666
Publisher: Acoustical Society of America (ASA)
Date: 03-2016
DOI: 10.1121/1.4944568
Abstract: Auditory localization research needs to be performed in more realistic testing environments to better capture the real-world abilities of listeners and their hearing devices. However, there are significant challenges involved in controlling the audibility of relevant target signals in realistic environments. To understand the important aspects influencing target detection in more complex environments, a reverberant room with a multi-talker background was simulated and presented to the listener in a loudspeaker-based virtual sound environment. Masked thresholds of a short speech stimulus were measured adaptively for multiple target source locations in this scenario. It was found that both distance and azimuth of the target source have a strong influence on the masked threshold. Subsequently, a functional model was applied to analyze the factors influencing target detectability. The model is comprised of an auditory front-end that generates an internal representation of the stimuli in both ears, followed by a decision device combining d′ information across time, frequency and both ears. The model predictions of the masked thresholds were overall in very good agreement with the experimental results. An analysis of the model processes showed that head shadow effects, signal spectrum, and reverberation have a strong impact on target audibility in the given scenario.
Publisher: Acoustical Society of America (ASA)
Date: 2019
DOI: 10.1121/1.5087567
Abstract: Estimating the basic acoustic parameters of conversational speech in noisy real-world conditions has been an elusive task in hearing research. Nevertheless, these data are essential ingredients for speech intelligibility tests and fitting rules for hearing aids. Previous surveys did not provide clear methodology for their acoustic measurements and setups, were opaque about their s les, or did not control for distance between the talker and listener, even though people are known to adapt their distance in noisy conversations. In the present study, conversations were elicited between pairs of people by asking them to play a collaborative game that required them to communicate. While performing this task, the subjects listened to binaural recordings of different everyday scenes, which were presented to them at their original sound pressure level (SPL) via highly open headphones. Their voices were recorded separately using calibrated headset microphones. The subjects were seated inside an anechoic chamber at 1 and 0.5 m distances. Precise estimates of realistic speech levels and signal-to-noise ratios (SNRs) were obtained for the different acoustic scenes, at broadband and third octave levels. It is shown that with acoustic background noise at above approximately 69 dB SPL at 1 m distance, or 75 dB SPL at 0.5 m, the average SNR can become negative. It is shown through interpolation of the two conditions that if the conversation partners would have been allowed to optimize their positions by moving closer to each other, then positive SNRs should be only observed above 75 dB SPL. The implications of the results on speech tests and hearing aid fitting rules are discussed.
Publisher: ASA
Date: 2013
DOI: 10.1121/1.4799505
Publisher: Acoustical Society of America (ASA)
Date: 2013
DOI: 10.1121/1.4770249
Abstract: Arweiler and Buchholz [J. Acoust. Soc. Am. 130, 996–1005 (2011)] showed that, while the energy of early reflections (ERs) in a room improves speech intelligibility, the benefit is smaller than that provided by the energy of the direct sound (DS). In terms of integration of ERs and DS, binaural listening did not provide a benefit from ERs apart from a binaural energy summation, such that monaural auditory processing could account for the data. However, a diffuse speech shaped noise (SSN) was used in the speech intelligibility experiments, which does not provide distinct binaural cues to the auditory system. In the present study, the monaural and binaural benefit from ERs for speech intelligibility was investigated using three directional maskers presented from 90° azimuth: a SSN, a multi-talker babble, and a reversed two-talker masker. For normal-hearing as well as hearing-impaired listeners, the directional and/or fluctuating (speech) maskers produced a similar benefit from ERs as obtained with the diffuse SSN, suggesting a monaural integration of the ERs and the DS for both types of maskers.
Publisher: Georg Thieme Verlag KG
Date: 07-2016
DOI: 10.3766/JAAA.15109
Abstract: Background: Deficits in spatial hearing can have a negative impact on listeners’ ability to orient in their environment and follow conversations in noisy backgrounds and may exacerbate the experience of hearing loss as a handicap. However, there are no good tools available for reliably capturing the spatial hearing abilities of listeners in complex acoustic environments containing multiple sounds of interest. Purpose: The purpose of this study was to explore a new method to measure auditory spatial analysis in a reverberant multitalker scenario. Research Design: This study was a descriptive case control study. Study S le: Ten listeners with normal hearing (NH) aged 20–31 yr and 16 listeners with hearing impairment (HI) aged 52–85 yr participated in the study. The latter group had symmetrical sensorineural hearing losses with a four-frequency average hearing loss of 29.7 dB HL. Data Collection and Analysis: A large reverberant room was simulated using a loudspeaker array in an anechoic chamber. In this simulated room, 96 scenes comprising between one and six concurrent talkers at different locations were generated. Listeners were presented with 45-sec s les of each scene, and were required to count, locate, and identify the gender of all talkers, using a graphical user interface on an iPad. Performance was evaluated in terms of correctly counting the sources and accuracy in localizing their direction. Results: Listeners with NH were able to reliably analyze scenes with up to four simultaneous talkers, while most listeners with hearing loss demonstrated errors even with two talkers at a time. Localization performance decreased in both groups with increasing number of talkers and was significantly poorer in listeners with HI. Overall performance was significantly correlated with hearing loss. Conclusions: This new method appears to be useful for estimating spatial abilities in realistic multitalker scenes. The method is sensitive to the number of sources in the scene, and to effects of sensorineural hearing loss. Further work will be needed to compare this method to more traditional single-source localization tests.
Publisher: Wissenschaftliche Verlagsgesellschaft mbH
Date: 07-2019
DOI: 10.3813/AAA.919349
Abstract: Everyday listening environments are characterized by far more complex spatial, spectral and temporal sound field distributions than the acoustic stimuli that are typically employed in controlled laboratory settings. As such, the reproduction of acoustic listening environments has become important for several research avenues related to sound perception, such as hearing loss rehabilitation, soundscapes, speech communication, auditory scene analysis, automatic scene classification, and room acoustics. However, the recordings of acoustic environments that are used as test material in these research areas are usually designed specifically for one study, or are provided in custom databases that cannot be universally adapted, beyond their original application. In this work we present the Ambisonic Recordings of Typical Environments (ARTE) database, which addresses several research needs simultaneously: realistic audio recordings that can be reproduced in 3D, 2D, or binaurally, with known acoustic properties, including absolute level and room impulse response. Multichannel higher-order ambisonic recordings of 13 realistic typical environments (e.g., office, cafè, dinner party, train station) were processed, acoustically analyzed, and subjectively evaluated to determine their perceived identity. The recordings are delivered in a generic format that may be reproduced with different hardware setups, and may also be used in binaural, or single-channel setups. Room impulse responses, as well as detailed acoustic analyses, of all environments supplement the recordings. The database is made open to the research community with the explicit intention to expand it in the future and include more scenes.
Publisher: IEEE
Date: 10-2013
Publisher: American Speech Language Hearing Association
Date: 26-02-2019
DOI: 10.1044/2018_JSLHR-H-18-0107
Abstract: The purpose of this study was to introduce a method of eliciting conversational behavior with many aspects of realism, which may be used to study the impacts of hearing impairment and noise on verbal communication to describe the characteristics of speech and language participants produced during the task and to assess participants' engagement and motivation while completing the task. Twenty young adults with normal hearing and 20 older adults with hearing impairment took part in face-to-face conversations while completing a referential communication puzzle task designed to elicit natural conversational speech production and language with a number of realistic characteristics. Participants rated the difficulty and relevance of acoustic scenes for communication and their engagement in conversations. The communication task elicited speech production in a natural conversational register and language with many realistic characteristics, including complex linguistic constructions and typical disfluencies found in everyday speech, and approximately balanced contributions within dyads. Subjective ratings suggest that the task is robust to learning and fatigue effects and that participants remained highly engaged throughout the experiment. All participants were able to maintain successful communication regardless of background noise level and degree of hearing impairment. The communication task described here may be used as part of a functional assessment of the ability to communicate in the presence of noise and hearing impairment. Although existing speech assessments have many strengths, they do not take into account the inherently interactive nature of spoken communication or the effects of motivation and engagement.
Publisher: Acoustical Society of America
Date: 2013
DOI: 10.1121/1.4800388
Publisher: Acoustical Society of America (ASA)
Date: 02-2017
DOI: 10.1121/1.4976191
Abstract: Westermann and Buchholz [(2015). J. Acoust. Soc. Am. 137(2), 757–767] found substantial improvements in speech reception thresholds (SRTs) for normal hearing listeners in a reverberant auditorium when the target talker was separated in distance from a two-talker masker. This study applied similar methodology, but tested listeners with a hearing impairment. On average, the participants received a 7 dB benefit in SRTs when the target was fixed at 0.5 m and the masker was moved from 0.5 to 10 m. But when the target was moved away, the SRTs increased by 5 dB. This indicates that hearing impaired listeners have difficulties suppressing nearby maskers while focusing attention on a far target.
Publisher: Acoustical Society of America (ASA)
Date: 10-2013
DOI: 10.1121/1.4817930
Abstract: The current experiment investigated whether better-ear glimpsing can explain the spatial release achieved by normal-hearing adults when situations are high in informational masking. Both modeling and behavioral methods were used. The speech reception thresholds of 38 young adults were measured for co-located, spatially separated and two better-ear glimpsed conditions. In the better-ear glimpsed conditions the binaural signals were processed so that in each time-frequency segment, the signal with the better SNR (left or right ear) was presented diotically. To investigate the effect of widening auditory filters on better-ear glimpsing, adjacent frequency bands were combined in one of the better-ear glimpsing conditions. Twenty-two participants were tested with maskers high in informational masking, while 16 participants were tested with maskers lower in informational masking. The mean speech reception thresholds achieved in the glimpsed conditions were significantly worse than in the spatially separated condition. This suggests that better-ear glimpsing can explain some but not all of the observed spatial release from masking. The difference between performance in the spatially separated and glimpsed conditions was largest when informational masking was high, suggesting better-ear glimpsing may release energetic rather than informational masking. Reducing the number of frequency bands s led had a small effect on performance.
Publisher: Acoustical Society of America (ASA)
Date: 11-07-2013
DOI: 10.1121/1.4812441
Abstract: Numerous studies have described improvements in speech understanding when interaural time differences (ITDs) and interaural level differences (ILDs) are present. The present study aimed to investigate whether either cue in isolation can elicit spatial release from masking (SRM) in a speech-on-speech masking paradigm with maskers positioned symmetrically around the listener. Twelve adults were tested using three presentations of the Listening in Spatialized Noise–Sentences Test, with each presentation modified to contain different interaural cues in the stimuli. Results suggest that ILDs provide a similar amount of SRM as ITDs and ILDs combined. ITDs alone provide significantly less benefit.
Publisher: Springer International Publishing
Date: 2016
DOI: 10.1007/978-3-319-25474-6_10
Abstract: Hearing loss has been shown to reduce speech understanding in spatialized multitalker listening situations, leading to the common belief that spatial processing is disrupted by hearing loss. This paper describes related studies from three laboratories that explored the contribution of reduced target audibility to this deficit. All studies used a stimulus configuration in which a speech target presented from the front was masked by speech maskers presented symmetrically from the sides. Together these studies highlight the importance of adequate stimulus audibility for optimal performance in spatialized speech mixtures and suggest that reduced access to target speech information might explain a substantial portion of the "spatial" deficit observed in listeners with hearing loss.
Publisher: Wissenschaftliche Verlagsgesellschaft mbH
Date: 2012
DOI: 10.3813/AAA.918491
Publisher: Informa UK Limited
Date: 21-08-2018
Publisher: ASA
Date: 2013
DOI: 10.1121/1.4799977
Publisher: Acoustical Society of America (ASA)
Date: 11-2020
DOI: 10.1121/10.0002660
Abstract: A binaural model predicting speech intelligibility in envelope-modulated noise for normal-hearing (NH) and hearing-impaired listeners is proposed. The study shows the importance of considering an internal noise with two components relying on the in idual audiogram and the level of the external stimuli. The model was optimized and verified using speech reception thresholds previously measured in three experiments involving NH and hearing-impaired listeners and sharing common methods. The anechoic target, in front of the listener, was presented simultaneously through headphones with two anechoic noise-vocoded speech maskers (VSs) either co-located with the target or spatially separated using an infinite broadband interaural level difference without crosstalk between ears. In experiment 1, two stationary noise maskers were also tested. In experiment 2, the VSs were presented at different sensation levels to vary audibility. In experiment 3, the effects of realistic interaural time and level differences were also tested. The model was applied to two datasets involving NH listeners to verify its backward compatibility. It was optimized to predict the data, leading to a correlation and mean absolute error between data and predictions above 0.93 and below 1.1 dB, respectively. The different internal noise approaches proposed in the literature to describe hearing impairment are discussed.
Publisher: American Speech Language Hearing Association
Date: 12-12-2022
DOI: 10.1044/2022_JSLHR-22-00218
Abstract: This study aimed to develop and test a measure of real-time continuous speech understanding to be used with natural dialogues. The measure was based on a category monitoring paradigm and employed five existing recordings of natural dialogues from which the different test categories and associated target words were derived. For each dialogue, a listener was first given a semantic category and asked to press a button as quickly as possible whenever they heard an instance of the category. We tested 63 younger adults, using five semantic categories (family, media, season, temperature, and travel) at three noise levels (in quiet, 0 dB, and −5 dB signal-to-noise ratio [SNR]). Performance was measured in terms of accuracy and response time. The results showed clear differences between the three noise conditions regardless of the semantic category. The peak of the response distribution was highest and earliest for the quiet condition and was reduced with decreasing SNR. The responses varied across categories, reflecting differences in the complexity of a given category or the typicality of the association between target words and their category. Broad categories and/or target words that were less directly associated with their category had decreased hit rates and increased response times. The results were discussed in terms of the sensitivity (hit rate) of the performance measure, as well as whether it picked up higher level semantic, context, and discourse properties of the dialogues. 0.23641/asha.21561681
Publisher: Acoustical Society of America (ASA)
Date: 04-2018
DOI: 10.1121/1.5031007
Abstract: Better-ear glimpsing (BEG) is an auditory phenomenon that helps understanding speech in noise by utilizing interaural level differences (ILDs). The benefit provided by BEG is limited in hearing-impaired (HI) listeners by reduced audibility at high frequencies. Rana and Buchholz [(2016). J. Acoust. Soc. Am. 140(2), 1192–1205] have shown that artificially enhancing ILDs at low and mid frequencies can help HI listeners understanding speech in noise, but the achieved benefit is smaller than in normal-hearing (NH) listeners. To understand how far this difference is explained by differences in audibility, audibility was carefully controlled here in ten NH and ten HI listeners and speech reception thresholds (SRTs) in noise were measured in a spatially separated and co-located condition as a function of frequency and sensation level. Maskers were realized by noise-vocoded speech and signals were spatialized using artificially generated broadband ILDs. The spatial benefit provided by BEG and SRTs improved consistently with increasing sensation level, but was limited in the HI listeners by loudness discomfort. Further, the HI listeners performed similar to NH listeners when differences in audibility were compensated. The results help to understand the hearing aid gain that is required to maximize the spatial benefit provided by ILDs as a function of frequency.
Publisher: Acoustical Society of America (ASA)
Date: 08-2011
DOI: 10.1121/1.3609258
Abstract: The auditory system takes advantage of early reflections (ERs) in a room by integrating them with the direct sound (DS) and thereby increasing the effective speech level. In the present paper the benefit from realistic ERs on speech intelligibility in diffuse speech-shaped noise was investigated for normal-hearing and hearing-impaired listeners. Monaural and binaural speech intelligibility tests were performed in a virtual auditory environment where the spectral characteristics of ERs from a simulated room could be preserved. The useful ER energy was derived from the speech intelligibility results and the efficiency of the ERs was determined as the ratio of the useful ER energy to the total ER energy. Even though ER energy contributed to speech intelligibility, DS energy was always more efficient, leading to better speech intelligibility for both groups of listeners. The efficiency loss for the ERs was mainly ascribed to their altered spectrum compared to the DS and to the filtering by the torso, head, and pinna. No binaural processing other than a binaural summation effect could be observed.
Publisher: IEEE
Date: 10-2013
Publisher: Wissenschaftliche Verlagsgesellschaft mbH
Date: 09-2013
DOI: 10.3813/AAA.918662
Publisher: Springer Berlin Heidelberg
Date: 2013
Publisher: Acoustical Society of America (ASA)
Date: 11-2015
DOI: 10.1121/1.4934732
Abstract: This study investigated to what extent spatial release from masking (SRM) deficits in hearing-impaired adults may be related to reduced audibility of the test stimuli. Sixteen adults with sensorineural hearing loss and 28 adults with normal hearing were assessed on the Listening in Spatialized Noise–Sentences test, which measures SRM using a symmetric speech-on-speech masking task. Stimuli for the hearing-impaired listeners were delivered using three lification levels (National Acoustic Laboratories - Revised Profound prescription (NAL-RP) +25%, and NAL-RP +50%), while stimuli for the normal-hearing group were filtered to achieve matched audibility. SRM increased as audibility increased for all participants. Thus, it is concluded that reduced audibility of stimuli may be a significant factor in hearing-impaired adults' reduced SRM even when hearing loss is compensated for with linear gain. However, the SRM achieved by the normal hearers with simulated audibility loss was still significantly greater than that achieved by hearing-impaired listeners, suggesting other factors besides audibility may still play a role.
Publisher: Acoustical Society of America (ASA)
Date: 08-2018
DOI: 10.1121/1.5051640
Abstract: Listening to speech in an environment with reverberation can be challenging for both the normal and impaired auditory system. However, it has been shown for both normal- and impaired-hearing listeners that it is the late reflections that are responsible for degrading intelligibility, whereas early reflections actually aid intelligibility by increasing the effective signal-to-noise ratio. Contrastingly, studies conducted with cochlear implant (CI) recipients have suggested that CI recipients have almost no tolerance for reverberation and that they are negatively impacted by both early and late reflections. The main objective of the current study is to re-evaluate the influence of reverberation on speech intelligibility in CI recipients using more authentic virtual auditory environments. Unlike previous studies in this area, this study was conducted using a loudspeaker-based auralization system rather than non-in idualized binaural room simulations. Speech intelligibility was measured in simulations of a range of actual physical rooms with plausible source−receiver distances, both with and without late reflections. The results show that the effect of reverberation is much smaller than previously suggested, especially with short source−receiver distances. Furthermore, the results suggest that, in contrast to previous literature, early reflections may not actually be detrimental to CI recipients.
Publisher: Acoustical Society of America (ASA)
Date: 10-2015
DOI: 10.1121/1.4931903
Abstract: Open plan classrooms, where several classes are in the same room, have recently re-emerged in Australian primary schools. This paper explores how the acoustics of four Kindergarten classrooms [an enclosed classroom (25 children), double classroom (44 children), fully open plan triple classroom (91 children), and a semi-open plan K–6 “21st century learning space” (205 children)] affect speech perception. Twenty-two to 23 5–6-year-old children in each classroom participated in an online four-picture choice speech perception test while adjacent classes engaged in quiet versus noisy activities. The noise levels recorded during the test were higher the larger the classroom, except in the noisy condition for the K–6 classroom, possibly due to acoustic treatments. Linear mixed effects models revealed children's performance accuracy and speed decreased as noise level increased. Additionally, children's speech perception abilities decreased the further away they were seated from the loudspeaker in noise levels above 50 dBA. These results suggest that fully open plan classrooms are not appropriate learning environments for critical listening activities with young children due to their high intrusive noise levels which negatively affect speech perception. If open plan classrooms are desired, they need to be acoustically designed to be appropriate for critical listening activities.
Publisher: American Speech Language Hearing Association
Date: 22-01-2019
DOI: 10.1044/2019_JSLHR-19-00201
Abstract: This article describes patterns of speech modifications produced by talkers as a function of the degree of hearing impairment of communication partners during naturalistic conversations in noise. An explanation of observed speech modifications is proposed in terms of a generalization of the concept of effort. This account complements existing theories of listening effort by extending the concept of effort to the domain of interactive communication. Twenty young adult normal hearing participants and 20 older adult hearing-impaired participants were tested in pairs. Each pair consisted of 1 young normal hearing participant and 1 older hearing-impaired participant. Pairs of participants took part in naturalistic conversations through the use of a referential communication task. Each pair completed a 5-min conversation in each of 5 different realistic acoustic environments. Talkers modified their speech, in terms of level and spectrum, in a gradient manner reflecting both the acoustic environment and the degree of hearing impairment of their conversation partner. All pairs of participants were able to maintain communication across all acoustic environments regardless of degree of hearing impairment and the level of environmental noise. Contrasting effects of noise and hearing impairment on speech production revealed distinct patterns of speech modifications produced by normal hearing and hearing-impaired talkers during conversation. This may reflect the fact that only the speech modifications produced by normal hearing talkers functioned to compensate for the hearing impairment of a conversation partner. The data presented support the concept of communication effort as a dynamic feedback system between conversation participants. Additionally, these results provide insight into the nature of realistic speech signals, which are encountered by people with hearing impairment in everyday communication scenarios.
Publisher: Georg Thieme Verlag KG
Date: 07-2016
DOI: 10.3766/JAAA.15094
Abstract: Background: Assessments of hearing aid (HA) benefits in the laboratory often do not accurately reflect real-life experience. This may be improved by employing loudspeaker-based virtual sound environments (VSEs) that provide more realistic acoustic scenarios. It is unclear how far the limited accuracy of these VSEs influences measures of subjective performance. Purpose: Verify two common methods for creating VSEs that are to be used for assessing HA outcomes. Research Design: A cocktail-party scene was created inside a meeting room and then reproduced with a 41-channel loudspeaker array inside an anechoic chamber. The reproduced scenes were created either by using room acoustic modeling techniques or microphone array recordings. Study S le: Participants were 18 listeners with a symmetrical, sloping, mild-to-moderate hearing loss, aged between 66 and 78 yr (mean = 73.8 yr). Data Collection and Analysis: The accuracy of the two VSEs was assessed by comparing the subjective performance measured with two-directional HA algorithms inside all three acoustic environments. The performance was evaluated by using a speech intelligibility test and an acceptable noise level task. Results: The general behavior of the subjective performance seen in the real environment was preserved in the two VSEs for both directional HA algorithms. However, the estimated directional benefits were slightly reduced in the model-based VSE, and further reduced in the recording-based VSE. Conclusions: It can be concluded that the considered VSEs can be used for testing directional HAs, but the provided sensitivity is reduced when compared to a real environment. This can result in an underestimation of the provided directional benefit. However, this minor limitation may be easily outweighed by the high realism of the acoustic scenes that these VSEs can generate, which may result in HA outcome measures with a significantly higher ecological relevance than provided by measures commonly performed in the laboratory or clinic.
Publisher: Acoustical Society of America (ASA)
Date: 11-2018
DOI: 10.1121/1.5078582
Abstract: Cubick and Dau [(2016). Acta Acust. Acust. 102, 547–557] showed that speech reception thresholds (SRTs) in noise, obtained with normal-hearing listeners, were significantly higher with hearing aids (HAs) than without. Some listeners reported a change in their spatial perception of the stimuli due to the HA processing, with auditory images often being broader and closer to the head or even internalized. The current study investigated whether worse speech intelligibility with HAs might be explained by distorted spatial perception and the resulting reduced ability to spatially segregate the target speech from the interferers. SRTs were measured in normal-hearing listeners with or without HAs in the presence of three interfering talkers or speech-shaped noises. Furthermore, listeners were asked to sketch their spatial perception of the acoustic scene. Consistent with the previous study, SRTs increased with HAs. Spatial release from masking was lower with HAs than without. The effects were similar for noise and speech maskers and appeared to be accounted for by changes to energetic masking. This interpretation was supported by results from a binaural speech intelligibility model. Even though the sketches indicated a change of spatial perception with HAs, no direct link between spatial perception and segregation of talkers could be shown.
Publisher: Informa UK Limited
Date: 09-07-2016
No related grants have been discovered for Joerg Buchholz.