|
|
Influence of the nasal cavities to human voice quality
Vampola, T. ; Horáček, Jaromír
Nasal cavities (NC) form the side branches of the human vocal tract and exhibit antiresonance and resonance properties which influence the produced voice quality. This study investigates the possibility of these resonances to contribute to the speaker's or singer's formant cluster around 3 - 5 kHz. A reduced finite element (FE) model was created which allows numerical simulation of the effects of changing the volumes of NC on the acoustic resonance and antiresonance characteristics of the vocal tract. This model, created from an accurate three-dimensional (3D) FE model of the human vocal tract for vowel [a:] and [i:] is computationally-effective and allows parametric changes of the volume connecting the nasal tract with the human vocal tract. Developed FE models of acoustic spaces of nasal and vocal tract for vowels /a:/ and /i:/ are used to study the influence of (NC) on phonation of these vowels. 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.
|
|
|
Measurement of acoustic input impedance of the human vocal tract models
Radolf, Vojtěch ; Dlask, P. ; Otčenášek, Z.
Input acoustic impedance of the human vocal tract models made of plexiglass was measured using the measurement system BIAS 6. Three models A, I, U for vowels /a:/, /i:/ and /u:/ had simplified rectangular shape of the channel with constant height 20 mm. The fourth model A2D had elliptical channel shape. Resulted resonance frequencies were within the known ranges of formant frequencies of the vowels. The resonances of default configurations varied for different boundary positions in relation to measuring microphone in the range of 0.5 %, 3.9 %, 2.1%, 6.7 % for the models A2D, A, I and U, respectively. The resonances of direct and reversed models with the output closed differed in the range of 0.5 % and 1.8 % for A2D and A model, respectively. The measured and computed resonances differed in the range from 3.8 % for A2D to 14.6 % for the model I.
|
|
|
Effect of the size of piriform sinuses on the voice quality
Vampola, T. ; Horáček, Jaromír
The influence of piriform sinuses (PS) on the resonance and antiresonance characteristics of the vocal tract is investigated. The change in sizes of PS cavities alters the resulting voice quality. Pilot studies reveal that additional formants caused by PS can occur in the frequency range of 3 – 5 kHz, i.e., in the range which is important for the production of the so called singer’s or speaker’s formant. This contribution therefore aims at investigating the influence of the side cavities of the vocal tract in more detail using two computational models of the vocal tract. First, is presented analysis of the influence of the acoustic spaces of PS on the existence of resonances and antiresonances in the spectra of the acoustic signal simulated using a reduced finite element (FE) model of the human vocal tract. Then the full FE model is used for the analysis by using direct numerical simulations of phonation.
|
guest ::
