Speech recognition in noise with active and passive hearing protectors: A comparative study

Bockstael, Annelies; Coensel, Bert De; Botteldooren, Dick; D’haenens, Wendy; Keppler, Hannah; Maes, Leen; Philips, Birgit; Swinnen, Freya; Vinck, Bart

doi:10.1121/1.3575599

Cited by 14 publications

(13 citation statements)

References 28 publications

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“…Wearers should listen to ambient sounds through the devices while they adjust them and recognize that they can make additional output adjustments as the ambient noise changes. A recent study investigating the benefits of active versus passive hearing protectors has revealed similar results 16 . The results of this study found that speech recognition of active and passive HPDs was highly de pendent on the background noise implemented.…”

Section: Discussionmentioning

confidence: 60%

An evaluation of sound restoration hearing protection devices and audibility issues in mining

Azman¹,

Hudak²

2011

Noise Control Eng. J.

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Section: Discussionmentioning

confidence: 60%

An evaluation of sound restoration hearing protection devices and audibility issues in mining

Azman¹,

Hudak²

2011

Noise Control Eng. J.

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“…A value that gives confidence to users that all critical communications will be understood would seem more desirable. The approach adopted here of optimizing speech SNR in separate subbands while avoiding signal compression eliminates the possibility of introducing electronic distortion that could compromise intelligibility (Bockstael et al, 2011). Moreover, a subband approach could be extended to persons with mild hearing loss, who could benefit from increased speech SNR (Plomp, 1986).…”

Section: Discussionmentioning

confidence: 99%

“…Most solutions have attempted to increase the speech signal-to-noise ratio (SNR) either directly or by influencing the upward spread of masking (Rankovic et al, 1992;Schwander and Levitt, 1987;Shields and Campbell, 2001;van Dijkhuizen et al, 1991). Understanding speech when wearing a communication headset/hearing protector (HPD) in a noisy environment introduces additional considerations (Abel et al, 2011;Bockstael et al, 2011;Giguère et al, 2011). There are two typical but fundamentally different situations.…”

Section: Introductionmentioning

confidence: 98%

Understanding speech when wearing communication headsets and hearing protectors with subband processing

Brammer

Bernstein

et al. 2014

The Journal of the Acoustical Society of America

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An adaptive, delayless, subband feed-forward control structure is employed to improve the speech signal-to-noise ratio (SNR) in the communication channel of a circumaural headset/hearing protector (HPD) from 90 Hz to 11.3 kHz, and to provide active noise control (ANC) from 50 to 800 Hz to complement the passive attenuation of the HPD. The task involves optimizing the speech SNR for each communication channel subband, subject to limiting the maximum sound level at the ear, maintaining a speech SNR preferred by users, and reducing large inter-band gain differences to improve speech quality. The performance of a proof-of-concept device has been evaluated in a pseudo-diffuse sound field when worn by human subjects under conditions of environmental noise and speech that do not pose a risk to hearing, and by simulation for other conditions. For the environmental noises employed in this study, subband speech SNR control combined with subband ANC produced greater improvement in word scores than subband ANC alone, and improved the consistency of word scores across subjects. The simulation employed a subject-specific linear model, and predicted that word scores are maintained in excess of 90% for sound levels outside the HPD of up to ∼115 dBA.

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“…As these are levels at the eardrum, which would have to undergo head-related transfer functions in order to scale them to free-space levels, these values are not directly comparable to directives for safe sound exposure levels which are all set for free/diffuse field exposure (Hammershøi and Møller 2008). However, for speech, the difference between in-ear and free-field levels can be estimated to be around 6 dB based on previous work with a similar measurement setup (Bockstael et al 2011). Based on this conversion, exposure levels fully complied with the 85 dB(A) level deemed to be safe for 8-hours exposure according to the European Directive for occupational noise exposure ("Directive 2003-10-EC on the Minimum Health and Safety Requirements Regarding the Exposure of Workers to the Risks Arising from Physical Agents (Noise)" 2003).…”

Section: Speech Intelligibility and Sound Exposurementioning

confidence: 99%

“…This would de facto result in a more advantageous signal-to-noise ratio at the side where the phone was held, because that ear is much more shielded from the background noise than the contralateral ear. In addition, it is known that a clear separation between signal and noise (one ear predominantly exposed to the noise, the other predominantly exposed to speech) improves speech intelligibility (Bockstael et al 2011). Especially in highest levels of background noise (car), shielding and spatial separation would have the most distinct effect and improve speech intelligibility scores.…”

Section: Simultaneous Exposure To Rf-emf and Sound Pressurementioning

confidence: 99%

Mobile phones: A trade-off between speech intelligibility and exposure to noise levels and to radio-frequency electromagnetic fields

Thielens

Bockstael

Declerck

et al. 2019

Environmental Research

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When making phone calls, cellphone and smartphone users are exposed to radio-frequency (RF) electromagnetic fields (EMFs) and sound pressure simultaneously. Speech intelligibility during mobile phone calls is related to the sound pressure level of speech relative to potential background sounds and also to the RF-EMF exposure, since the signal quality is correlated with the RF-EMF strength. Additionally, speech intelligibility, sound pressure level, and exposure to RF-EMFs are dependent on how the call is made (on speaker, held at the ear, or with headsets). The relationship between speech intelligibility, sound exposure, and exposure to RF-EMFs is determined in this study. To this aim, the transmitted RF-EMF power was recorded during phone calls made by 53 subjects in three different, controlled exposure scenarios: calling with the phone at the ear, calling in speaker-mode, and calling with a headset. This emitted power is directly proportional to the exposure to RF EMFs and is translated into specific absorption rate using numerical simulations. Simultaneously, sound pressure levels have been recorded and speech intelligibility has been assessed during each phone call. The results show that exposure to RF-EMFs, quantified as the specific absorption in the head, will be reduced when speaker-mode or a headset is used, in comparison to calling next to the ear. Additionally, personal exposure to sound pressure is also found to be highest in the condition where the phone is held next to the ear. On the other hand, speech perception is found to be the best when calling with a phone next to the ear in comparison to the other studied conditions, when background noise is present. Thielens et al., 2013). These values were then renormalized to a TX power of 1 W. We chose not to model the wire of the headset in the 'Headset' configuration. Data Processing and AnalysisThe registered TX powers during each call were pooled for all participants, calls and frequencies, but split for the three exposure conditions, the two locations, and the communication technology. We chose to split the data for the two locations, since the coverage and link with the network might have been different. We chose to split the data for the different telecommunication technologies since they have distinctly different ranges of operation in terms of emitted power. We did not split the GSM results in 900 MHz and 1800 MHz. A Wilcoxon Rank Sum (WRS) test and a two-sided Kolmogorov-Smirnov (K-S) test were then used to determine whether the TX power in different exposure situations on the same test site were significantly different (significance level of 5%). In a second step, all TX powers that were recorded for GSM were multiplied by the SAR brain values at the appropriate frequency and exposure condition. Those instances where WCDMA was used to establish communication were not treated for SAR, because we did not have full information on the used frequency during those events. However, they were considered for the analysis of emitted powers. The obtained...

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Speech recognition in noise with active and passive hearing protectors: A comparative study

Cited by 14 publications

References 28 publications

An evaluation of sound restoration hearing protection devices and audibility issues in mining

An evaluation of sound restoration hearing protection devices and audibility issues in mining

Understanding speech when wearing communication headsets and hearing protectors with subband processing

Mobile phones: A trade-off between speech intelligibility and exposure to noise levels and to radio-frequency electromagnetic fields

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