Reverberant overlap- and self-masking in consonant identification

Nábělek, Anna K.; Łȩtowski, Tomasz; Tucker, Frances M.

doi:10.1121/1.398740

Cited by 149 publications

(111 citation statements)

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“…Reverberant sound energy typically creates a temporal "smearing" of speech that imposes overlap masking on contiguous phonemes, lengthens the durations of words, and fills quiet and/or low-intensity speech segments with unwanted sound ͑Bolt and MacDonald, 1949; Houtgast and Steeneken, 1985;Nabelek et al, 1989;Dreschler and Leeuw, 1990;Helfer, 1994;Culling et al, 2003͒. As a result, intelligibility decreases in conjunction with the reductions in speech envelope modulation depth imposed by temporal smearing ͑Houtgast and Steeneken, 1985͒.…”

Section: Introductionmentioning

confidence: 99%

Effects of source-to-listener distance and masking on perception of cochlear implant processed speech in reverberant rooms

Whitmal

Poissant

2009

The Journal of the Acoustical Society of America

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Two experiments examined the effects of source-to-listener distance ͑SLD͒ on sentence recognition in simulations of cochlear implant usage in noisy, reverberant rooms. Experiment 1 tested sentence recognition for three locations in the reverberant field of a small classroom ͑volume= 79.2 m 3 ͒. Subjects listened to sentences mixed with speech-spectrum noise that were processed with simulated reverberation followed by either vocoding ͑6, 12, or 24 spectral channels͒ or no further processing. Results indicated that changes in SLD within a small room produced only minor changes in recognition performance, a finding likely related to the listener remaining in the reverberant field. Experiment 2 tested sentence recognition for a simulated six-channel implant in a larger classroom ͑volume= 175.9 m 3 ͒ with varying levels of reverberation that could place the three listening locations in either the direct or reverberant field of the room. Results indicated that reducing SLD did improve performance, particularly when direct sound dominated the signal, but did not completely eliminate the effects of reverberation. Scores for both experiments were predicted accurately from speech transmission index values that modeled the effects of SLD, reverberation, and noise in terms of their effects on modulations of the speech envelope. Such models may prove to be a useful predictive tool for evaluating the quality of listening environments for cochlear implant users.

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Section: Introductionmentioning

confidence: 99%

Effects of source-to-listener distance and masking on perception of cochlear implant processed speech in reverberant rooms

Whitmal

Poissant

2009

The Journal of the Acoustical Society of America

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“…These portions have high energy and therefore cause a large amount of ''overlapmasking'' (i.e. reverberation tails mask the following phonemes) [6], but these portions are relatively less important for syllable perception compared with spectral transitions [7]. Therefore, SSS reduces the effect of overlap-masking with little degradation of the information needed for speech perception.…”

Section: Introductionmentioning

confidence: 99%

Comparison of consonant identification improvements by steady-state suppression via a loudspeaker system between with and without natural sounds from a talker in reverberation

Hodoshima

Svensson

Arai

2009

Acoust. Sci. & Tech.

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“…It has been reported that the main cause of degradation in speech intelligibility in reverberant environments is overlap-masking [3][4][5]. Because of overlap-masking, reverberant components of prior speech segments mask successive segments.…”

Section: Introductionmentioning

confidence: 99%

Inverse correlation of intelligibility of speech in reverberation with the amount of overlap-masking

Arai

Murakami

Hayashi

et al. 2007

Acoust. Sci. & Tech.

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IntroductionLate reflections degrade speech intelligibility [1], whereas early reflections often help speech intelligibility, and this is called the Haas effect (e.g., [2]). It has been reported that the main cause of degradation in speech intelligibility in reverberant environments is overlap-masking [3][4][5]. Because of overlap-masking, reverberant components of prior speech segments mask successive segments. As a result, speech segments following reverberating segments are more difficult to understand. As the energy of the prior segments increases, the effect of overlap-masking also increases. This is particularly important when the preceding segment is a vowel, which has more power, and the subsequent segment is a consonant, which has less power [6,7].A number of researches have proposed and discussed how the intelligibility of speech in reverberation can be estimated from an impulse response of a room. Reverberation time, such as T 60 , is a simple objective parameter for estimating reverberation [8]. Speech intelligibility usually decreases as T 60 becomes longer, but different rooms having the same T 60 might yield different degrees of speech intelligibility. One example is the case where T 60 is the same in different rooms, but the energy ratios of the direct-to-reverberated sounds are different. The Deutlichkeit value, such as D 50 [9,10] and Clarity, such as C 50 [9,11], take this direct-to-reverberation ratio into account. The speech transmission index (STI) is another parameter that is widely used to measure speech intelligibility objectively [12,13]. STI is based on the fact that the modulation transfer function depends on reverberation [14].The intelligibility of speech also depends on the speech signal itself. To reduce overlap-masking, Arai et al. [6,7] proposed ''steady-state suppression'' as a preprocess for speech signals in reverberant environments. Strange et al. [15] showed that the information in steady-state portions of a speech signal was relatively insignificant compared with the information in transient portions. Additionally, steady-state portions usually have more energy compared with transient portions. In the ''steady-state suppression'' technique, overlapmasking is reduced by estimating and suppressing steady-state

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Reverberant overlap- and self-masking in consonant identification

Cited by 149 publications

References 0 publications

Effects of source-to-listener distance and masking on perception of cochlear implant processed speech in reverberant rooms

Effects of source-to-listener distance and masking on perception of cochlear implant processed speech in reverberant rooms

Comparison of consonant identification improvements by steady-state suppression via a loudspeaker system between with and without natural sounds from a talker in reverberation

Inverse correlation of intelligibility of speech in reverberation with the amount of overlap-masking

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