Speech intelligibility for non-native listeners in auditoria with noise (original) (raw)
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The Journal of the Acoustical Society of America, 1994
The effect of articulating clearly on speech intelligibility is analyzed for ten normal-hearing and two hearing-impaired listeners in noisy, reverberant, and combined environments. Clear speech is more intelligible than conversational speech for each listener in every environment. The difference in intelligibility due to speaking style increases as noise and/or reverberation increase. The average difference in intelligibility is 20 percentage points for the normal-hearing listeners and 26 percentage points for the hearing-impaired listeners. Two predictors of intelligibility are used to quantify the environmental degradations: The articulation index (AI) and the speech transmission index (STI). Both are shown to predict, reliably, performance levels within a speaking style for normal-hearing listeners. The AI is unable to represent the reduction in intelligibility scores due to reverberation for the hearing-impaired listeners. Neither predictor can account for the difference in inte...
Trends in hearing, 2015
The aim of the present study was to determine the relations between the intelligibility of speech in noise and measures of auditory resolution, loudness recruitment, and cognitive function. The analyses were based on data published earlier as part of the presentation of the Auditory Profile, a test battery implemented in four languages. Tests of the intelligibility of speech, resolution, loudness recruitment, and lexical decision making were measured using headphones in five centers: in Germany, the Netherlands, Sweden, and the United Kingdom. Correlations and stepwise linear regression models were calculated. In sum, 72 hearing-impaired listeners aged 22 to 91 years with a broad range of hearing losses were included in the study. Several significant correlations were found with the intelligibility of speech in noise. Stepwise linear regression analyses showed that pure-tone average, age, spectral and temporal resolution, and loudness recruitment were significant predictors of the intelligibility of speech in fluctuating noise. Complex interrelationships between auditory factors and the intelligibility of speech in noise were revealed using the Auditory Profile data set in four languages. After taking into account the effects of pure-tone average and age, spectral and temporal resolution and loudness recruitment had an added value in the prediction of variation among listeners with respect to the intelligibility of speech in noise. The results of the lexical decision making test were not related to the intelligibility of speech in noise, in the population studied.
Automated Subjective Assessment of Speech Intelligibility in Various Listening Modes
Microsystems, Electronics and Acoustics
In this paper, the results of automated subjective assessment of Ukrainian speech intelligibility are presented. Speech monosyllables of the consonant-vowel-consonant (CVC) type were listened in two modes: through headphones and through acoustic monitors. The assessment was carried out with the help of specially developed software that allowed automating of articulation tests. Speech listening was done for four situations: pure language; speech distorted by noise; speech distorted by reverberation; speech distorted by the combined effect of noise and reverberation. In the first case, speech monosyllables of 3 articulation tables were listened, each of which contained 50 monosyllables. In the second case, speech distorted by the additive noise with the signal-to-noise ratios (SNR) varied in the range-15…+10 dB was listened. In this case, models of white, pink and brown noises were used, the masking properties of which are rather well-studied. In the third case, the reverberant speech for reverberation times in the range 0.3…2.7 s was modeled by convolution of pure speech signals with room impulse responces (RIRs) of various rooms, and in the fourth case the joint action of pink noise and reverberation was considered. It turned out that the masking ability of white noise exceeds one for brown noise for SNR less than minus 5 dB, which is not entirely consistent with preliminary predictive estimates. In addition, it turned out that listening to speech distorted by noise through acoustic monitors could lead to a significant increase in the speech intelligibility, compared to the case of listening through headphones. The analysis of possible causes of abnormal increase in speech intelligibility has been carried out. Early reflections, presence of two loudspeakers, binaural listening, psychophysical features of listeners, as well as peculiarities of software and articulatory testing organization were considered as possible reasons of the phenomenon. After correction of the software and some features of articulation tests it turned out that the results of the speech intelligibility estimation almost coincide when listening to the signals through the headphones and through acoustic monitors, if the distance between the listener and acoustic monitors does not exceed 0.6-0.8 meters. At the same time, these corrections did not differ in the behavior of the dependencies of speech intelligibility on the SNR for small (less minus 5 dB) SNR values The general conclusion may be that listening to speech signals distorted by noise and reverberation interferences, performed with the application of the proposed automated system of articulation tests, indicates the performance and high quality of the developed system. Ref. 13, fig. 7.
2021
One of the conditions for getting high-quality education is good intelligibility of the teacher’s speech in the places where students are sitting. Meanwhile, the level of a speech signal decreases at an increase in distance between a listener and a teacher, which is especially noticeable in large lecture rooms. Since there is always noise in rooms (movement and conversations of nearby listeners, noise of a fan or an air conditioner, etc.), a signal level may not be high enough to ensure good speech intelligibility. Listeners with partial loss of hearing, the ones with hearing aids and cochlear implants are especially susceptible to harmful effects of noise. Even the category of listeners with normal hearing, such as pupils of elementary school, is more prone to harmful effects of noise on speech intelligibility than middle and high school students. The masking effect of noise is partly compensated by the sound reflection from different surfaces (ceiling, walls, floor, furniture, etc...
Background noise level and reverberation time are the standard parameters used to evaluate speech understanding in a classroom. This space can be excited by an outdoor source of noise even when it has an acoustic treatment. The room geometry, usually rectangular, creates differences in the signal-to-noise ratio S/N between all listening positions due to eigenmodes. In the present study, 5 listening positions are used in a standard size classroom excited by a virtual source of pink noise. This source is placed in a corner to represent an external noise source. Using the matrix sentence method developed by Hochmuth et al. [Int. J. of Audiology, 51, 536–544 (2012)], 300 sentences from a virtual speaker are used as the signal source located at the opposite corner. In the reference point at the center of the room speech source is adjusted to a L Aeq of 65 dBA. Noise source is adjusted to reach a A-weighted S/N (S/N(A)) of approximately-3 dB at this point. The level difference among the positions is less than 3.2 dB considering the S/N(A) but can reach more than 8 dB considering the S/N. Both sources are recorded simultaneously with a dummy head in all positions. A subjective test is then performed with headphones to evaluate intelligibility in these listening points. Room acoustic parameters for intelligibility, D 50 , STI, S/N and S/N(A), are compared with the subjective test results. Results show that speech recognition is different between all points but no correlation can be found with the objective parameters. In this context, intelligibility is not being affected by room eigenmodes.
Effect of reverberation on speech intelligibility, logatom test “in situ”
2015
The influence of acoustic parameters of lecture halls is essential for the quality of reception and the understanding of the content. One of the basic acoustic parameters is the reverberation time in the room. The study demonstrates that the room which is not properly designed for acoustics, causes difficulty in understanding the delivered text. Selected acoustic parameters were analyzed, such as reverberation time, acoustic background, and delivered text intelligibility. A possible solution was proposed, using reflecting and absorbing surfaces appropriately positioned in the room.
Perceptual analysis of the speech intelligibility and soundscape of multilingual environments
Applied Acoustics, 2019
This paper examines the perceived speech intelligibility of English, Polish, Arabic, and Mandarin and, more generally, the soundscape associated to multilingual environments. Listening tests were used to evaluate three acoustic environments (an airport, a hospital, and a café) under three room acoustic conditions defined by a different speech transmission index (STI) (STI=0.4, 0.5 and 0.6). In the tests, participants rated eleven semantic attributes representative of speech perception and the overall soundscape (speech intelligibility, speech level, speech pleasantness, noisiness, annoyance, relaxation, comfort, environment pleasantness, eventfulness, excitement, and familiarity). Results obtained indicate that inter-language comparisons based on perceived speech intelligibility are different from those obtained from objective speech intelligibility tests. Noticeably, English participants were found to be most sensitive to changes in room acoustic conditions and to meaningful and distractive noise sources, whilst Arab participants were least sensitive to changes in room acoustic conditions and more tolerant to noise. Perceived speech intelligibility correlated significantly with non-acoustical factors (speech pleasantness, comfort and environment pleasantness), and 'emotional factors' (annoyance, relaxation, comfort and environment pleasantness) explained a large portion of the variance in soundscape assessment. Results also showed that language affected the perceived speech intelligibility marginally (p = 0.051) and noisiness significantly (p = 0.047), the latter being the best indicator of cultural variations amongst the attributes tested. Overall, the study shows that designing for speech intelligibility cannot be solely based on room acoustic parameters, especially in the case of multilingual environments.
The Journal of the Acoustical Society of America, 2013
Previous studies have demonstrated the negative impact of adverse signal-to-noise-ratios on non-native English-speaking listeners' performance on speech recognition using recall tasks, as well as implied that comprehension skills were more impaired than recognition skills under reverberation and noise. The authors have themselves previously conducted a pilot study on three native and three non-native Englishspeaking listeners to examine the effects of reverberation and noise using speech comprehension tasks. Those results suggested that speech comprehension performance is worse under longer reverberation times (RT), and that a longer RT is more detrimental to speech comprehension by non-native listeners than native listeners. This paper reports on the refined full study, in which a larger number (up to 30) of each group was tested. Each participant was exposed to 15 acoustic conditions, created from combinations of five RTs (0.4 to 1.2 seconds) and three background noise levels (RC-30, 40 and 50). Speech comprehension performance under each condition was recorded. Confounders related to general speech comprehension abilities were screened for, including listening span, oral comprehension abilities and English verbal skills. Results are presented and compared between native and non-native listeners.
Using listening effort assessment in the acoustical design of rooms for speech
Building and Environment, 2018
This study addresses the issue of an enhanced acoustical design of rooms for speech, which besides targeting high speech intelligibility also ensures minimal effort in speech reception. Speech-in-noise tests in the Italian language were proposed to normal-hearing young adults, both in situ, within an existing university classroom, and via headphones, using auralized signals obtained from acoustic simulations of the same environment. Later, auralization was used to investigate the effect of realistic modifications to the room acoustics (acoustical treatment of a wall, change of the room size) by altering the virtual model of the classroom. The speech reception performance was characterized by using both the number of words correctly recognized (speech intelligibility, IS) and two estimates of listening effort: the behavioral measure of response time (RT) and a subjective judgement on a rating scale (LE). Firstly, the correspondence between the IS, RT and LE results in situ and in auralized conditions was considered and discussed. Then, the effectiveness of the three metrics in outlining the effect of the acoustic changes of the room was analyzed. The results showed that there were no differences between the compared acoustic conditions in terms of IS. The effects of the characteristics of the room acoustics were instead discriminated when RT and LE were considered, with the greatest number of significant differences observed by using RT. Using RT therefore seems to be an effective and promising strategy to better discern the effects of the room acoustics and to enhance the acoustical design of rooms for speech.
2017
Classrooms acoustics can affect students ́ speech intelligibility and learning performance depending on its background noise level and/or reverberation. Speech intelligibility is usually assessed in real classrooms through a subjective approach, by performing speech intelligibility tests, or through an objective approach, by evaluating speech transmission index (STI) from impulse response, speech and noise level measurements. An acoustic simulation technique makes it possible to assess acoustical conditions for speech reception in virtual environments, thus allowing for predicting intelligibility before a classroom is built or renovated. However, in order to obtain reliable results, the simulation model needs to be calibrated and validated with in-situ measurements. The aim of this work is to compare tests performed in-situ on a group of people, with tests performed on the same people by reproducing the auralized test signal through headphones, in terms of intelligibility scores (IS...