Speech is easier to understand in continuous noise than in noise which is switched on at the beginning of the speech and off at the end. It is suggested that this is due to some adaptation process. In order to test this hypothesis a series of experiments have been performed in which the intelligibility of plosives in isolated syllables was measured as a function of the duration of the preceding noise. The spectrum of the noise was also varied. It was found that the adaptation, as measured by the mean increase in intelligibility, increased as the duration of the noise preceding the syllable was lengthened. It was also found that the adaptation varied with the centre frequency of the spectrum of the noise. The amount of adaptation was negatively correlated with the threshold of hearing.

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Bibliographic reference.  Ainsworth, William A. / Cervera, T. (2001): "Effects of noise adaptation on the perception of voiced plosives in isolated syllables", In EUROSPEECH-2001, 371-374.