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Relation between own voice perception and skull vibrations
Vokřál, J. ; Horáček, Jaromír ; Černý, L. ; Veselý, Jan
Human own voice is percepted differently by speaker via air and bone conduction. The main aim of previous studies was to find out transfer function between these two ways of listening. Psychoacoustics methods, which were used mostly, gave relatively high differences between different subjects. Simultaneous recording of subject voice and vibrations of skull was used in your study. Low-pass filter effects found in vibrational spectra correspond to the psychoacoustics studies. These findings could be helpful in studying of self-perception of voice colour, the investigation of signer voice, the remediation of articulation disorders.
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Numerical modelling of production of czech vowel /a/ based on FE model of vocal tract
Švancara, P. ; Horáček, Jaromír ; Pešek, Luděk
Finite element (FE) model of the human vocal tract foe Czech vowel /a/ created by magnetic resonance imaging (MR) technique is modified to obtain radiation boundary condition outside the lips and used for numerical simulations. First resonant characteristics of FE model are studied using transient analysis boy pulse excitation and modal analysis. Then the pronunciation of the Czech vowel /a/ is simulated in time domain. Calculated time and frequency responses are compared with experimental data.
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Bifurcation phenomena in vocal fold vibrations - experiments in vitro
Horáček, Jaromír ; Švec, J. ; Veselý, Jan
The study presents experimental investigations focused on monitoring of the non-linear vibration effects, especially bifurcation phenomena in the vibration of human vocal folds. The experiments were performed with excised human larynges excited by airflow. Sudden changes between different regimes of the vocal fold vibration were observed when smoothly changing the tension of the vocal folds. The study reveals further details on the nature of sudden changes between voice registers. The results also point out the possible relationship between regular (physiologic) and irregular (pathologic) vocal fold oscillations.
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Model of vocal fold oscillation in viscous fluid flow
Horáček, Jaromír
A vibrating element on an elastic foundation in the wall of a channel conveying air approximates the vocal fold oscillations. The viscous incompressible 1-D fluid flow theory is used and a generally defined shape of the vocal fold is considered. The numerical solution yields the instability thresholds, which are close to the known physiological data for phonation thresholds. The viscosity is important for very small opening of the glottis where its effect on instability boundaries increases.
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Finite element modelling of viscous incompressible fluid flow in glottis
Damašek, Alexandr ; Burda, P.
he paper deals with numericalcomputations of viscous incompressible fluid flow in glottis describedby Navier-Stokes equations and discretized bythe finite element method. Navier-Stokes equations with the nonlinearterm are discretized by semiimplicit integration scheme. Forhigher Reynolds number fluid flow Streamline Upwind Petrov-Galerkin Method - SUPG. This method uses special weight functions which modify shape functions based on the Galerkin principle.
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