Acoustical and Perceptual Comparison of Noise Reduction and Compression in Hearing Aids

2015 ◽  
Vol 58 (4) ◽  
pp. 1363-1376 ◽  
Author(s):  
Inge Brons ◽  
Rolph Houben ◽  
Wouter A. Dreschler
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Noise Levels ◽  
Dynamic Range Compression ◽  
Perceptual Comparison ◽  
Babble Noise ◽  
Processing Differences

Purpose Noise reduction and dynamic-range compression are generally applied together in hearing aids but may have opposite effects on amplification. This study evaluated the acoustical and perceptual effects of separate and combined processing of noise reduction and compression. Design Recordings of the output of 4 hearing aids for speech in babble noise at +4 dB signal-to-noise ratio were used in 3 experiments: (a) acoustical measurements to determine the influence of processing on speech and noise levels; (b) perceptual measurements to determine the detectability of processing differences for 16 listeners with hearing impairment; and (c) perceptual measurements to determine the effect of processing on speech intelligibility, noise annoyance, speech naturalness, and overall preference. Results Noise reduction and compression processing differed between hearing aids. The combined processing (noise reduction with compression) most strongly reduced noise and speech levels. The combined processing was detectably different between hearing aids, but compression processing alone was not. The combined processing did not influence speech intelligibility. Preference for combined processing was lower than previously observed for noise reduction without compression. Conclusions Differences in processing between hearing aids are perceptually salient. The effect of compression should be taken into account during the development and evaluation of hearing aid noise reduction.

scholarly journals Perceptual Evaluation of Signal-to-Noise-Ratio-Aware Dynamic Range Compression in Hearing Aids

2020 ◽  
Vol 24 ◽  
pp. 233121652093053
Author(s):  
Borys Kowalewski ◽  
Torsten Dau ◽  
Tobias May
Keyword(s):  
Hearing Aids ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Perceptual Evaluation ◽  
Dynamic Range Compression ◽  
Subjective Preference ◽  
Noise Ratio ◽  
Fast Acting

Dynamic range compression is a compensation strategy commonly used in modern hearing aids. Fast-acting systems respond relatively quickly to the fluctuations in the input level. This allows for more effective compression of the dynamic range of speech and hence enhanced the audibility of its low-intensity components. However, such processing also amplifies the background noise, distorts the modulation spectra of both the speech and the background, and can reduce the output signal-to-noise ratio (SNR). Recently, May et al. proposed a novel SNR-aware compression strategy, in which the compression speed is adapted depending on whether speech is present or absent. Fast-acting compression is applied to speech-dominated time–frequency (T-F) units, while noise-dominated T-F units are processed using slow-acting compression. It has been shown that this strategy provides a similar effective compression of the speech dynamic range as conventional fast-acting compression, while introducing fewer distortions of the modulation spectrum of the background and providing an improved output SNR. In this study, this SNR-aware compression strategy was compared with conventional fast- and slow-acting compression in terms of speech intelligibility and subjective preference in a group of 17 hearing-impaired listeners with varying degree of hearing loss. The results show a speech intelligibility benefit of the SNR-aware compression strategy over the conventional slow-acting system. Furthermore, the SNR-aware approach demonstrates an increased subjective preference compared with both conventional fast- and slow-acting systems.

scholarly journals Enhancement of Speech Intelligibility using Binary Mask Based on Noise Constraints

2019 ◽  
Vol 8 (3) ◽  
pp. 3509-3516
Keyword(s):  
Hearing Aids ◽  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Random Noise ◽  
Wiener Filter ◽  
Binary Mask ◽  
Gain Function ◽  
Magnitude Spectrum ◽  
Objective Tests ◽  
Babble Noise

The primary aim of this paper is to examine the application of binary mask to improve intelligibility in most unfavorable conditions where hearing impaired/normal listeners find it difficult to understand what is being told. Most of the existing noise reduction algorithms are known to improve the speech quality but they hardly improve speech intelligibility. The paper proposed by Gibak Kim and Philipos C. Loizou uses the Weiner gain function for improving speech intelligibility. Here, in this paper we have proposed to apply the same approach in magnitude spectrum using the parametric wiener filter in order to study its effects on overall speech intelligibility. Subjective and objective tests were conducted to evaluate the performance of the enhanced speech for various types of noises. The results clearly indicate that there is an improvement in average segmental signal-to-noise ratio for the speech corrupted at -5dB, 0dB, 5dB and 10dB SNR values for random noise, babble noise, car noise and helicopter noise. This technique can be used in real time applications, such as mobile, hearing aids and speech–activated machines

scholarly journals Intelligibility and Clarity of Reverberant Speech: Effects of Wide Dynamic Range Compression Release Time and Working Memory

2016 ◽  
Vol 59 (6) ◽  
pp. 1543-1554 ◽  
Author(s):  
Paul N. Reinhart ◽  
Pamela E. Souza
Keyword(s):  
Working Memory ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Release Time ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Release Times ◽  
Memory Group ◽  
Reverberant Speech

Purpose The purpose of this study was to examine the effects of varying wide dynamic range compression (WDRC) release time on intelligibility and clarity of reverberant speech. The study also considered the role of individual working memory. Method Thirty older listeners with mild to moderately-severe sloping sensorineural hearing loss participated. Individuals were divided into high and low working memory groups on the basis of the results of a reading span test. Participants listened binaurally to sentence stimuli simulated at a range of reverberation conditions and WDRC release times using a high compression ratio. Outcome measures included objective intelligibility and subjective clarity ratings. Results Speech intelligibility and clarity ratings both decreased as a function of reverberation. The low working memory group demonstrated a greater decrease in intelligibility with increasing amounts of reverberation than the high working memory group. Both groups, regardless of working memory, had higher speech intelligibility and clarity ratings with longer WDRC release times. WDRC release time had a larger effect on speech intelligibility under more reverberant conditions. Conclusions Reverberation significantly affects speech intelligibility, particularly for individuals with lower working memory. In addition, longer release times in hearing aids may improve listener speech intelligibility and clarity in reverberant environments.

A combined multi-channel Wiener filter-based noise reduction and dynamic range compression in hearing aids

2012 ◽  
Vol 92 (2) ◽  
pp. 417-426 ◽  
Author(s):  
Kim Ngo ◽  
Ann Spriet ◽  
Marc Moonen ◽  
Jan Wouters ◽  
Søren Holdt Jensen
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Dynamic Range ◽  
Wiener Filter ◽  
Dynamic Range Compression

scholarly journals Signal-to-Noise-Ratio-Aware Dynamic Range Compression in Hearing Aids

2018 ◽  
Vol 22 ◽  
pp. 233121651879090 ◽  
Author(s):  
Tobias May ◽  
Borys Kowalewski ◽  
Torsten Dau
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Dynamic Range Compression ◽  
Noise Ratio

Performance Improvement of Digital Hearing Aid Systems

2015 ◽  
Vol 1 ◽  
pp. 27
Author(s):  
Isiaka Ajewale Alimi
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Digital Signal Processor ◽  
Speech Intelligibility ◽  
Communication Systems ◽  
Hearing Aid ◽  
Spectral Subtraction ◽  
Residual Spectrum ◽  
Digital Hearing Aids ◽  
Digital Hearing Aid

Digital hearing aids addresses the issues of noise and speech intelligibility that is associated with the analogue types. One of the main functions of the digital signal processor (DSP) of digital hearing aid systems is noise reduction which can be achieved by speech enhancement algorithms which in turn improve system performance and flexibility. However, studies have shown that the quality of experience (QoE) with some of the current hearing aids is not up to expectation in a noisy environment due to interfering sound, background noise and reverberation. It is also suggested that noise reduction features of the DSP can be further improved accordingly. Recently, we proposed an adaptive spectral subtraction algorithm to enhance the performance of communication systems and address the issue of associated musical noise generated by the conventional spectral subtraction algorithm. The effectiveness of the algorithm has been confirmed by different objective and subjective evaluations. In this study, an adaptive spectral subtraction algorithm is implemented using the noise-estimation algorithm for highly non-stationary noisy environments instead of the voice activity detection (VAD) employed in our previous work due to its effectiveness. Also, signal to residual spectrum ratio (SR) is implemented in order to control the amplification distortion for speech intelligibility improvement. The results show that the proposed scheme gives comparatively better performance and can be easily employed in digital hearing aid system for improving speech quality and intelligibility.

scholarly journals Measuring the Influence of Noise Reduction on Listening Effort in Hearing-Impaired Listeners Using Response Times to an Arithmetic Task in Noise

2021 ◽  
Vol 25 ◽  
pp. 233121652110144
Author(s):  
Ilja Reinten ◽  
Inge De Ronde-Brons ◽  
Rolph Houben ◽  
Wouter Dreschler
Keyword(s):  
Noise Reduction ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Response Times ◽  
Hearing Impaired ◽  
Listening Effort ◽  
Arithmetic Task ◽  
Test Retest Reliability ◽  
Influence Of Noise ◽  
Measured Response

Single microphone noise reduction (NR) in hearing aids can provide a subjective benefit even when there is no objective improvement in speech intelligibility. A possible explanation lies in a reduction of listening effort. Previously, we showed that response times (a proxy for listening effort) to an auditory-only dual-task were reduced by NR in normal-hearing (NH) listeners. In this study, we investigate if the results from NH listeners extend to the hearing-impaired (HI), the target group for hearing aids. In addition, we assess the relevance of the outcome measure for studying and understanding listening effort. Twelve HI subjects were asked to sum two digits of a digit triplet in noise. We measured response times to this task, as well as subjective listening effort and speech intelligibility. Stimuli were presented at three signal-to-noise ratios (SNR; –5, 0, +5 dB) and in quiet. Stimuli were processed with ideal or nonideal NR, or unprocessed. The effect of NR on response times in HI listeners was significant only in conditions where speech intelligibility was also affected (–5 dB SNR). This is in contrast to the previous results with NH listeners. There was a significant effect of SNR on response times for HI listeners. The response time measure was reasonably correlated ( R142 = 0.54) to subjective listening effort and showed a sufficient test–retest reliability. This study thus presents an objective, valid, and reliable measure for evaluating an aspect of listening effort of HI listeners.

A 1-Channel 3-Band Wide Dynamic Range Compression Chip for Vibration Transducer of Implantable Hearing Aids

2014 ◽  
Vol 24 (1) ◽  
pp. 1009-1017 ◽  
Author(s):  
DongWook Kim ◽  
KiWoong Seong ◽  
MyoungNam Kim ◽  
JinHo Cho ◽  
JyungHyun Lee
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Vibration Transducer ◽  
Implantable Hearing Aids
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