Effect of Compression Ratio on Speech Recognition and Speech-Quality Ratings With Wide Dynamic Range Compression Amplification

2000 ◽  
Vol 43 (2) ◽  
pp. 456-468 ◽  
Author(s):  
Kumiko T. Boike ◽  
Pamela E. Souza
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Compression Ratio ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Speech Quality ◽  
Control Group ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Quality Ratings

This project examined the effect of varying compression ratio on speech recognition and quality. Both listeners with mild-to-moderate sensorineural hearing loss and a control group of listeners with normal hearing participated. Test materials were sentences from the Connected Speech Test (R. M. Cox, G. C. Alexander, & C. Gilmore, 1987) which were digitally processed with linear amplification and wide dynamic range compression amplification with 3 compression ratios. Speech-recognition scores were obtained with sentences in quiet and in noise at a 10-dB signal-to-noise ratio for each amplification condition. Additionally, the participants rated each amplification condition in terms of clarity, pleasantness, ease of understanding, and overall impression. Results indicated that, for speech in quiet, compression ratio had no effect on speech-recognition scores; however, speech-quality ratings decreased as compression ratio increased. For speech in noise, both speech-recognition scores and ratings decreased with increasing compression ratio for the listeners with hearing loss. These results suggest that selection of compression ratio on the basis of speech-quality judgments does not compromise speech recognition.

Effect of Slow-Acting Wide Dynamic Range Compression on Measures of Intelligibility and Ratings of Speech Quality in Simulated-Loss Listeners

2005 ◽  
Vol 48 (3) ◽  
pp. 702-714 ◽  
Author(s):  
Peninah S. Rosengard ◽  
Karen L. Payton ◽  
Louis D. Braida
Keyword(s):  
Hearing Loss ◽  
Speech Intelligibility ◽  
Dynamic Range ◽  
Speech Quality ◽  
Subjective Ratings ◽  
Subjective Measures ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Amplitude Compression ◽  
Moderate Hearing Loss

The purpose of this study was twofold: (a) to determine the extent to which 4-channel, slow-acting wide dynamic range amplitude compression (WDRC) can counteract the perceptual effects of reduced auditory dynamic range and (b) to examine the relation between objective measures of speech intelligibility and categorical ratings of speech quality for sentences processed with slow-acting WDRC. Multiband expansion was used to simulate the effects of elevated thresholds and loudness recruitment in normal hearing listeners. While some previous studies have shown that WDRC can improve both speech intelligibility and quality, others have found no benefit. The current experiment shows that moderate amounts of compression can provide a small but significant improvement in speech intelligibility, relative to linear amplification, for simulated-loss listeners with small dynamic ranges (i.e., flat, moderate hearing loss). This benefit was found for speech at conversational levels, both in quiet and in a background of babble. Simulated-loss listeners with large dynamic ranges (i.e., sloping, mild-to-moderate hearing loss) did not show any improvement. Comparison of speech intelligibility scores and subjective ratings of intelligibility showed that listeners with simulated hearing loss could accurately judge the overall intelligibility of speech. However, in all listeners, ratings of pleasantness decreased as the compression ratio increased. These findings suggest that subjective measures of speech quality should be used in conjunction with either objective or subjective measures of speech intelligibility to ensure that participant-selected hearing aid parameters optimize both comfort and intelligibility.

Wide Dynamic Range Compression Improves Speech Recognition

ASHA Leader ◽  
2013 ◽  
Vol 18 (8) ◽  
pp. 37-37
Keyword(s):  
Speech Recognition ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression

Wide Dynamic Range Compression Improves Speech Recognition

Comparison of Multichannel Wide Dynamic Range Compression and ChannelFree Processing in Open Canal Hearing Instruments

2013 ◽  
Vol 24 (02) ◽  
pp. 126-137 ◽  
Author(s):  
Patrick N. Plyler ◽  
Monika Bertges Reber ◽  
Amanda Kovach ◽  
Elisabeth Galloway ◽  
Elizabeth Humphrey
Keyword(s):  
Signal Processing ◽  
Hearing Loss ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
Repeated Measures Design ◽  
Dynamic Range Compression ◽  
Processing Strategies ◽  
Hearing Instruments

Background: Multichannel wide dynamic range compression (WDRC) and ChannelFree processing have similar goals yet differ significantly in terms of signal processing. Multichannel WDRC devices divide the input signal into separate frequency bands; a separate level is determined within each frequency band; and compression in each band is based on the level within each band. ChannelFree processing detects the wideband level, and gain adjustments are based on the wideband signal level and adjusted up to 20,000 times per second. Although both signal processing strategies are currently available in hearing aids, it is unclear if differences in these signal processing strategies affect the performance and/or preference of the end user. Purpose: The purpose of the research was to determine the effects of multichannel wide dynamic range compression and ChannelFree processing on performance and/or preference of listeners using open-canal hearing instruments. Research Design: An experimental study in which subjects were exposed to a repeated measures design was utilized. Study Sample: Fourteen adult listeners with mild sloping to moderately severe sensorineural hearing loss participated (mean age 67 yr). Data Collection and Analysis: Participants completed two 5 wk trial periods for each signal processing strategy. Probe microphone, behavioral and subjective measures were conducted unaided and aided at the end of each trial period. Results: Behavioral and subjective results for both signal processing strategies were significantly better than unaided results; however, behavioral and subjective results were not significantly different between the signal processing strategies. Conclusions: Multichannel WDRC and ChannelFree processing are both effective signal processing strategies that provide significant benefit for hearing instrument users. Overall preference between the strategies may be related to the degree of hearing loss of the user, high-frequency in-situ levels, and/or acceptance of background noise.

scholarly journals Factors Affecting the Accessibility of Voice Telephony for People with Hearing Loss: Audio Encoding, Network Impairments, Video and Environmental Noise

2021 ◽  
Vol 14 (4) ◽  
pp. 1-35
Author(s):  
Linda Kozma-Spytek ◽  
Christian Vogler
Keyword(s):  
Hearing Loss ◽  
Speech Recognition ◽  
Packet Loss ◽  
Mental Effort ◽  
Quality Parameters ◽  
Speech Quality ◽  
Audio Quality ◽  
Presentation Modes ◽  
Quality Ratings ◽  
The Impact

This paper describes four studies with a total of 114 individuals with hearing loss and 12 hearing controls that investigate the impact of audio quality parameters on voice telecommunications. These studies were first informed by a survey of 439 individuals with hearing loss on their voice telecommunications experiences. While voice telephony was very important, with high usage of wireless mobile phones, respondents reported relatively low satisfaction with their hearing devices’ performance for telephone listening, noting that improved telephone audio quality was a significant need. The studies cover three categories of audio quality parameters: (1) narrowband (NB) versus wideband (WB) audio; (2) encoding audio at varying bit rates, from typical rates used in today's mobile networks to the highest quality supported by these audio codecs; and (3) absence of packet loss to worst-case packet loss in both mobile and VoIP networks. Additionally, NB versus WB audio was tested in auditory-only and audiovisual presentation modes and in quiet and noisy environments. With WB audio in a quiet environment, individuals with hearing loss exhibited better speech recognition, expended less perceived mental effort, and rated speech quality higher than with NB audio. WB audio provided a greater benefit when listening alone than when the visual channel also was available. The noisy environment significantly degraded performance for both presentation modes, but particularly for listening alone. Bit rate affected speech recognition for NB audio, and speech quality ratings for both NB and WB audio. Packet loss affected all of speech recognition, mental effort, and speech quality ratings. WB versus NB audio also affected hearing individuals, especially under packet loss. These results are discussed in terms of the practical steps they suggest for the implementation of telecommunications systems and related technical standards and policy considerations to improve the accessibility of voice telephony for people with hearing loss.

Measuring the Long-Term SNRs of Static and Adaptive Compression Amplification Techniques for Speech in Noise

2013 ◽  
Vol 24 (08) ◽  
pp. 671-683 ◽  
Author(s):  
Ying-Hui Lai ◽  
Pei-Chun Li ◽  
Kuen-Shian Tsai ◽  
Woei-Chyn Chu ◽  
Shuenn-Tsong Young
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Dynamic Range ◽  
Wide Dynamic Range ◽  
High Frequency Hearing Loss ◽  
Digital Hearing Aids ◽  
Speech In Noise ◽  
Dynamic Range Compression ◽  
Adaptive Compression

Background: Multichannel wide-dynamic-range compression (WDRC) is a widely adopted amplification scheme in modern digital hearing aids. It attempts to provide individuals with loudness recruitment with superior speech intelligibility and greater listening comfort over a wider range of input levels. However, recent surveys have shown that compression processing (operating in the nonlinear regime) usually reduces the long-term signal-to-noise ratio (SNR). Purpose: The purpose of this study was to determine the long-term SNR in an adaptive compression-ratio (CR) amplification scheme called adaptive wide-dynamic-range compression (AWDRC), and to determine whether this concept is better than static WDRC amplification at improving the long-term SNR for speech in noise. Design and Study Sample: AWDRC uses the input short-term dynamic range to adjust the CR to maximize audibility and comfort. Various methods for evaluating the long-term SNR were used to observe the relationship between the CR and output SNR performance in AWDRC for seven typical audiograms, and to compare the results with those for static WDRC amplification. Results: The results showed that the variation of the CR in AWDRC amplification can maintain the comfort and audibility of the output sound. In addition, the average long-term SNR improved by 0.1–5.5 dB for a flat hearing loss, by 0.2–3.4 dB for a reverse sloping hearing loss, by 1.4–4.8 dB for a high-frequency hearing loss, and by 0.3–5.7 dB for a mild-to-moderate-sloping high-frequency hearing loss relative to static WDRC amplification. The output long-term SNR differed significantly (p < .001) between static WDRC and AWDRC amplification. Conclusions: The results of this study show that AWDRC, which uses the characteristics of the input signal to adaptively adjust the CR, provides better long-term SNR performance than static WDRC amplification.

scholarly journals Temporal Resolution With a Prescriptive Fitting Formula

2013 ◽  
Vol 22 (2) ◽  
pp. 216-225 ◽  
Author(s):  
Marc A. Brennan ◽  
Frederick J. Gallun ◽  
Pamela E. Souza ◽  
G. Christopher Stecker
Keyword(s):  
Hearing Loss ◽  
Temporal Resolution ◽  
Dynamic Range ◽  
Gap Detection ◽  
Linear Amplification ◽  
Wide Dynamic Range ◽  
Detection Thresholds ◽  
Dynamic Range Compression ◽  
Fitting Method ◽  
Moderate Hearing Loss

Purpose Authors of previous work using laboratory-based paradigms documented that wide dynamic range compression (WDRC) may improve gap detection compared to linear amplification. The purpose of this study was to measure temporal resolution using WDRC fit with compression ratios set for each listener's hearing loss. Method Nineteen adults with mild-to-moderate hearing loss fitted with WDRC or linear amplification set to a prescriptive fitting method participated in this study. Subjects detected amplitude modulations and gaps. Two types of noise carrier were used: narrowband (1995–2005 Hz) and broadband (100–8000 Hz). Results Small differences between WDRC and linear amplification were observed in the measures of temporal resolution. Modulation detection thresholds worsened by a mean of 0.7 dB with WDRC compared to linear amplification. This reduction was observed for both carrier types. Gap detection thresholds did not differ between the 2 amplification conditions. Conclusions WDRC set using a prescriptive fitting method with individualized compression ratios had a small but statistically significant effect on measures of modulation thresholds. Differences were not observed between the two amplification conditions for the measures of gap detection. These findings contrast with previous work using fixed compression ratios, suggesting that the effect of the fitting method on the compression ratio should be considered when attempting to generalize the effect of WDRC on temporal resolution to the clinical setting.

Speech and Music Quality Ratings for Linear and Nonlinear Hearing Aid Circuitry

2007 ◽  
Vol 18 (08) ◽  
pp. 688-699 ◽  
Author(s):  
Evelyn Davies-Venn ◽  
Pamela Souza ◽  
David Fabry
Keyword(s):  
Hearing Aids ◽  
Dynamic Range ◽  
Hearing Aid ◽  
Significant Preference ◽  
Wide Dynamic Range ◽  
Dynamic Range Compression ◽  
Quality Ratings ◽  
Linear And Nonlinear ◽  
Moderate Hearing Loss

This study evaluated quality ratings for speech and music stimuli processed using peak clipping (PC), compression limiting (CL), and wide-dynamic range compression (WDRC) hearing aid circuitry. Eighteen listeners with mild-to-moderate hearing loss were binaurally fitted with behind-the-ear (BTE) hearing aids and instructed to rate the quality of speech under various conditions in quiet and noise and two genres of music. Results for speech revealed a slight preference for WDRC at 80 dB SPL, and equivalent ratings for the three circuits under all other listening conditions. Music ratings revealed a marginally significant preference for WDRC and a preference for classical over popular music. For music, judgments on pleasantness were the most influential on overall circuit preference. Este estudio evalúa estimaciones de calidad para estímulos de lenguaje y música procesados usando corte de picos (PC), limitación de la compresión (CL) y compresión de rango dinámico amplio (WDRC) en los circuitos del auxiliar auditivo. Dieciocho sujetos con hipoacusia leve a moderada fueron adaptados binauralmente con auxiliares auditivos retroauriculares (BTE) e instruidos para juzgar la calidad del lenguaje bajo varias condiciones de silencio y ruido, y la de dos géneros de música. Los resultados para el lenguaje revelaron una ligera preferencia para el WDRC a 80 dB SPL, y estimaciones equivalentes para los tres circuitos en las otras condiciones de escucha. Las estimaciones para la música revelaron una preferencia marginalmente significativa para el WDRC y una preferencia para la música clásica por encima de la popular. Para la música, los juicios de agradabilidad fueron los que más influyeron en la preferencia global de los circuitos.

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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