Formant amplitude in the perception of /i/ and /u/
Michael Kiefte, Teresa Enright, L. Gerald Marshall · The Journal of the Acoustical Society of America · 2007
Although recent evidence reconfirmed the importance of spectral peaks in vowel identification [M. Kiefte and K.R. Kluender, J. Acoust. Soc. Am. 117, 1395–1404 (2005)], the roles of formant bandwidth and amplitude in perception have not been firmly established. Although several studies have shown changes in vowel categorization with changes in bandwidth and amplitude, such manipulations often result in peaks that have very little local spectral contrast or which may be perceptually masked by other spectral prominences. This study compares local contrast and masking of spectral peaks in vowel perception. A stimulus continuum ranging from /i/ to /u/ in both the amplitude of the second formant as well as that of higher formants was presented to listeners for identification. Both full-spectrum and incomplete-spectrum stimuli were used to demonstrate the effects of local spectral contrast and simultaneous masking. A second experiment was used to determine if listeners were able to detect the presence of the second spectral peak in the same stimuli. Results from both experiments indicated that both masking and spectral contrast play a role in vowel perception.