PERCEPTUAL EVALUATION OF FE MODELLED CONSEQUENCES OF TONSILLECTOMY:
DIFFERENCES BETWEEN LISTENERS
A-M. Laukkanen, J. Horácek, P. Švancara, E. Lehtinen, T. Waaramaa
This study compared musicians’ (N 5) and speech students’(N 10) perceptual evaluations of simulated sound samples. Computer simulations of Czech vowels were made, both including the computed resonance effects of large tonsils (size 1.6 cm3) and without tonsils. The simulations were made using a Finite Element model of the vocal tract, based on magnetic resonance images. Size and shape of the tonsils were obtained from clinical data. The simulations of vowels /a:, e:, i:, o:, u:/ with and without tonsils were evaluated for general voice quality and timbre. Formant frequencies of the samples were also measured. The samples with and without tonsils did not differ significantly from each other for voice quality (Wilcoxon Signed Rank Test, p > 0.05). The timbre was significantly darker without tonsils (p="0.028)" and F3 was significantly lower (p="0.043)." In speech students’ evaluations, voice quality and timbre correlated with F3 (r = 0.80, p="0.002" for quality; r="0.58," p="0.049" for timbre). In musicians’ evaluations there was no correlation between timbre and formant frequencies. Timbre and quality correlated with each other in both groups (r="0.66," p="0.02" for speech students, r="0.61," p="0.033" for musicians), brighter timbre was considered better. Musicians’ and speech students’ evaluations differed for voice quality (Mann Whitney Test, p="0.000," speech students regarded the quality as worse in general) but not for timbre. The results suggest that (1) the effects of a tonsillectomy can be perceivable, (2) the listeners´ background education is important when evaluating the sound quality in simulations of human voice.
Key Words: modeling, simulation, tonsillectomy, voice quality, timbre, musicians, speech students
A-M. Laukkanen1, J. Horácek2, P. Švancara2, E. Lehtinen1 , T. Waaramaa1
1 Dept. of Speech Communication and Voice Research, FIN-33014 University of Tampere, Finland,
E-Mail: Anne-Maria.Laukkanen@uta.fi, Elina.Lehtinen@uta.fi, Teija.Waaramaa@uta.fi;
2Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Dolejskova 5, Prague 8, 18200, Czech Republic,
E-Mail: jaromirh@it.cas.cz, svancara@fme.vutbr.cz