Identification of vowels with equated intensity. A preliminary study.

The ability of listeners to identify 10 vowels under two conditions was investigated. In both conditions the vowels were presented at a comfortable loudness level in a constant phonetic environment with equal stress. In the first condition, the vowels were presented with their natural intensity differences, and in the second condition they were presented with their intensities equated. The role of relative intensity differences for the identification of vowel sounds at various loudness levels is discussed, and the likelihood that intensity differences play a more important role in identifying those vowel sounds having similar characteristics (i.e., formant frequencies ranges) is considered.