Why is the formant frequency difference limen asymmetric?
Hynek Heřmanský · The Journal of the Acoustical Society of America · 1987
Flanagan [J. Acoust. Soc. Am. 27, 613–617 (1955)] observed asymmetries in formant frequency difference limen in the perception of some synthesized vowel-like sounds and attributed those asymmetries to the proximity of neighboring formants. This hypothesis about the origin of the asymmetries in the perception of differences in vowel formant position is tangible and is widely accepted. The perceptual experiments of Hermansky and Jaykin [J. Acoust. Soc. Am. Suppl. 1 80, S18 (1986)] showed that the asymmetries in formant frequency difference limen can be reversed by small changes in fundamental frequency in the experiment. This observation questions the contribution of neighboring formants as a factor in the perception of small differences in formant position. Results of experiments in the perception of synthetic vowel-like sounds will be presented. They suggest that the formant distribution was not a major factor contributing to perceptual asymmetries in Flanagan's experiment. The role of formant structure in vowel perception is discussed.