Difference limen for formant frequency discrimination at high fundamental frequencies

In previous studies of formant frequency discrimination, variation in the stimuli has mainly concerned the formant frequencies while other factors which may affect formant frequency discrimination have largely been ignored. In most studies, fundamental frequencies typical of adult male speakers have been used. In the study presented here, formant frequency discrimination as a function of fundamental frequency level was studied. Contrary to expectations, fundamental frequency level did not seem to affect formant frequency discrimination. This was true even when the fundamental frequency was higher than the tested formant frequency. The implication of these findings is that formant frequency discrimination must, at least partly, rely on some other mechanism than reconstruction of the vocal tract transfer function. It is suggested that listeners use differences in the amplitude of partials to discriminate between complex vowel like sounds. Asymmetries in the distribution of these amplitudes may also explain the corresponding asymmetries found in perception.