On the forward masking threshold of vowels in vc-combinations

This report deals with the question whether we may expect the masking of a final voiceless plosive by a preceding vowel in normal speech. With experiments on forward masking by, among other things, synthetic vowels (Lopes Cardozo and Van Nierop, this issue) it was observed that the auditory threshold is about 15 dB elevated just after (up to 20 ms) the vowel and falls to its normal level in about 150 ms. In normal speech we find loudness levels of about 25-40 dBSL of the noise part of the plosives at a loudness level of 60 dBSL of the vowel (Lopes Cardozo and De Jong, this issue) and duration of the silent interval in voiceless plosives up to 100 ms (Slis and Cohen 1969). The forward masking effect of the vowel on the final consonant can be artificially enhanced in two ways, viz.: (1) by attenuating the consonant (2) by advancing the consonant in time; in this way it is shifted closer to the vowel.