Ptacek P H, Koutstaal C W
J Am Audiol Soc. 1977 Mar-Apr;2(5):169-72.
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.
研究了听众在两种条件下识别10个元音的能力。在这两种条件下，元音均以舒适的响度水平在语音环境恒定且重音相等的情况下呈现。在第一种条件下，元音以其自然强度差异呈现，在第二种条件下，元音以强度相等的方式呈现。讨论了相对强度差异在不同响度水平下对元音识别的作用，并考虑了强度差异在识别具有相似特征（即共振峰频率范围）的元音时发挥更重要作用的可能性。
