National Repository of Grey Literature 27 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Acoustic characteristics of 3D human vocal tract model with nasal cavities – preliminary experimental results
Radolf, Vojtěch ; Horáček, Jaromír ; Košina, Jan ; Vampola, T.
Acoustic resonance characteristics of 3D human vocal tract model with nasal and paranasal cavities were measured in three different ways: The excitation was realized by (1) self-oscillating vocal folds replica, (2) by a swept harmonic signal from an earphone placed instead of the vocal folds and (3) by a white noise signal from a loudspeaker located in front of the open mouth of the model. Resulting resonance frequencies are comparable for all excitation signals. These experiments were carried out to verify a complex mathematical model.
Experimental investigation of acoustic characteristics of 3D human vocal tract model with nasal cavities
Radolf, Vojtěch ; Horáček, Jaromír ; Košina, Jan ; Vampola, T.
The following experiments were carried out to be later used in the verification of a complex\nmathematical model of human voice production. Acoustic resonance characteristics of a 3D human voca tract model without and with nasal and paranasal cavities were measured in two different ways: The excitation was realized by (1) self-oscillating vocal folds replica and (2) by sine-tone sweeps from an earphone placed instead of the vocal folds. The resulting resonance and antiresonance frequencies were found to be comparable for both excitation signals.
Numerical investigation of acoustic characteristics of 3D human vocal tract model with nasal cavities
Vampola, T. ; Štorkán, J. ; Horáček, Jaromír ; Radolf, Vojtěch
Acoustic resonance characteristics of 3D human vocal tract model without and with nasal and\nparanasal cavities were computed. Nasal cavities (NC) form the side branches of the human vocal tract and exhibit antiresonance and resonance properties which influence the produced voice quality. Developed FE models of acoustic spaces of nasal and vocal tract for vowel /a:/ are used to study the influence of (NC) on phonation. Acoustics frequency-modal characteristics are studied by modal analysis and numerical simulation of acoustic signals in time domain is performed by transient analysis of the FE models.
Experimental modelling of phonation using artificial models of human vocal folds and vocal tracts
Horáček, Jaromír ; Radolf, Vojtěch ; Bula, Vítězslav ; Košina, Jan
The study provides information on experimental research on a complete 1:1 scaled model of human phonation. The model includes human lungs, the trachea, the laryngeal part with artificial vocal folds and the vocal tracts designed for different vowels. The measurement set up enables modelling the time signals not easily measured in humans during phonation as for example fluctuations of the subglottic, laryngeal and oral pressures measured simultaneously with the glottis opening and the glottis area registered by a high-speed camera. The simulation of phonation is performed in the ranges of the airflow rate and the subglottic pressure typical for a normal humans' physiology.
Effect of a soft tissue on vocal tract acoustic resonance properties in vocal exercises using phonation into tubes
Radolf, Vojtěch ; Horáček, Jaromír ; Laukkanen, A. M.
Mathematical model is introduced to clarify the influence of the vocal tract soft tissues on the acoustic resonance (formant) frequencies. The influence is studied in the context of voice therapy technique that uses phonation into tubes. Strong acoustc-structural interaction is demonstrated to take place in the vocal tract when it is prolonged by a tube with the distal end in air or submerged 2 cm and 10 cm in water. The numerical results from the model are compared with the resonance frequencies measured in humans.
Experimental investigation of phonation using artificial models of human vocal folds and vocal tract
Horáček, Jaromír ; Radolf, Vojtěch ; Bula, Vítězslav ; Košina, Jan ; Vampola, T. ; Dušková, Miroslava
The contribution presents results of in vitro measurements of voicing performed on originally developed models of the human vocal folds and vocal tract. The designed models are based on CT and MRI measurements of human subject during phonation. The measured phonation (aerodynamic, vibration and acoustic) chacteristics are comparable with values found in humans.
Phonation characteristics of self-oscillating vocal folds replica with and without the model of the human vocal tract
Horáček, Jaromír ; Bula, Vítězslav ; Košina, Jan ; Radolf, Vojtěch
The experimental study presents in vitro measurements of phonation characteristics performed on the developed 1:1 scaled replica of human vocal folds. The aerodynamic, vibration and acoustic characteristics measured with and without the model of the human vocal tract for vowel [u:] are compared.
ENGINEERING MECHANICS 2016 - Book of full texts
Zolotarev, Igor ; Radolf, Vojtěch
The 22nd International Conference EM2016 aims to provide a forum for researchers, industry practitioners, engineers and postgraduate scholars to promote exchange and disseminate knowledge and experiences of the most recent results and advances in a wide range of topics in Engineering Mechanics, including, but not limited to: Biomechanics, Dynamics, Fluid Mechanics, Fracture Mechanics, Kinematics, Mechanics of Solids, Mechatronics, Reliability of Structures and Thermomechanics.
Acoustic resonance characteristics of the human vocal tract with respect to a soft tissue
Radolf, Vojtěch ; Horáček, Jaromír
A mathematical model, which can help to clarify physical background of an influence of the soft tissue of vocal cavities on the formant frequencies, has been extended. Strong acoustic-structural interaction is demonstrated on the vocal tract cavity for vowel /u:/ prolonged by a tube that is used for voice training and therapy purposes. The glottis is closed by a yielding wall, considering a mass, compliance and structural damping. Viscous losses of the acoustic cavities and radiation impedance at the output are assumed. Significant change in the first acoustic resonance frequency caused by the compliance of the soft tissue at the glottis corresponds to the data found experimentally in earlier study.
Acoustic-structural interaction in human vocal tract prolonged by a tube
Radolf, Vojtěch ; Horáček, Jaromír
Phonation into tubes is often used for voice training and therapy. This paper introduces a mathematical model, which can help to clarify physical background of an influence of the soft tissues of vocal cavities on the acoustic resonances (formant frequencies). Substantial change in the first formant frequency caused by the soft tissues in the human vocal tract is in principle in the acoustic-structural interaction of the acoustic cavity semiocluded by the tube, with the yielding wall created for example by the soft tissues in the larynx.

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