Resonance frequencies of the vocal tract have traditionally been modelled using one-dimensional models. These cannot accurately represent the events in the frequency region of the formant cluster around 2.5-4.5 kHz, however. Here, the vocal tract resonance frequencies and their mode shapes are studied using a three-dimensional finite element model obtained from computed tomography measurements of a subject phonating on vowel [a:]. Instead of the traditional five, up to eight resonance frequencies of the vocal tract were found below the prominent antiresonance around 4.7 kHz. The three extra resonances were found to correspond to modes which were axially asymmetric and involved the piriform sinuses, valleculae, and transverse vibrations in the oral cavity. The results therefore suggest that the phenomenon of speaker's and singer's formant clustering may be more complex than originally thought.

Faculty of Mechanical Engineering Czech Technical University Prague Department of Mechanics Biomechanics and Mechatronics Technická 4 Prague 6 Prague 16607 Czech Republic

References provided by Crossref.org

Application of nonlinear dynamics theory to understanding normal and pathologic voices in humans

Toward a consensus on symbolic notation of harmonics, resonances, and formants in vocalization