Relationship between fundamental and formant frequencies in voice preference.

Covariation in the size of laryngeal and vocal tract structures leads to a moderate correlation between fundamental frequency (F0) and formant frequencies (FFs) in natural speech. A method of adjustment procedure was used to test whether listeners prefer combinations of F0 and FFs that reflect this covariation. Vowel sequences spoken by two men and two women were processed by the STRAIGHT vocoder to construct three sets of frequency-shifted continua. The distributions of "best choice" responses in all three experiments confirm that listeners prefer coordinated patterns of F0 and FF similar to those of natural speech.