KLINKERT, A. & MAURER, D. (1997):
Fourier spectra and formant patterns of German vowels produced at F0 of 70 - 850
Hz. Journal of the Acoustical Society of America, 101, 5, 3112.
Presentation at the 133rd meeting of the Acoustical Society of America, June 1997
Previous studies of vowel synthesis and of natural vowels have indicated (1) a correlation between the lower formants and F0 for F0 > 175 Hz, (2) intelligibility and spectral differences of vowels with high F0 > 500 Hz, (3) severe methodological problems of formant frequency estimation for F0 > 300 Hz, (4) formant number alterations (appearence of different numbers of relevant formants for one vowel), (5) formant pattern ambiguity (appearence of the same formant pattern for different vowels). The purpose of this study was to replicate these findings. A large sample of the German vowels /i,y,e,(slashed oh) ,(cursive beta) ,(open aye) ,o,u/ produced in isolation as well as in CVC context was investigated. 18,674 recordings were made of 35 men, 44 women, and 20 children. Isolated vowels were produced at different levels of F0, and with different intensities. A listening test was performed. Fourier spectra, LPC spectra and spectral constancy were analyzed. The results strongly support the five indications mentioned. In particular for isolated vowel sounds the correlation between the formants and F0, the appearence of "one-formant back vowels" (only one appearent formant < 2 kHz), and the formant pattern ambiguity for non-adjacent vowels proved to be very pronounced. Consequences for normalization approaches are discussed