Elite vocal performers heavily use their voices. Thus, they are more susceptible to voice disorders than general people. Many acoustic studies have been conducted on vocalists among elite vocal performers. In addition, VHI and V-RQOL, methods of subjective evaluation on voice use, have been conducted focusing on classical singer. However, there are few studies dealing with classical singing students making an effort to become elite vocal performers. Thus, the purpose of this study is to examine the acoustic characteristics of classical singing students and determine their vocal effort.
To this end, this study targeted 17 soprano classical singing students majoring in voice performance in a university (freshmen, sophomores, and juniors) and 18 general students (women) attending the same school, aged 20-25. In order to examine the characteristics of formant and spectral domain of each group, vowels /a/, /i/, and /u/ were used. Data collection procedure was as follows. Each group was made to phonate carrier phrases including vowels /a/, /i/, and /u/ at habitual pitch, and then, to phonate the vowels at C4 (261Hz) pitch and F4 (349Hz) pitch for five seconds, that is, sustained phonation. Then, only soprano classical singing students were made to record their classical vocalization containing vibrato. The study results can be summarized as below.
First, in both the groups, the variables of formant and spectral domain related to the vowels among carrier phrases showed statistically inconsistent differences. These differences are thought to be owing to their habitual differences in vocalization.
Second, at formant domain, F3 showed statistically significant differences in sustained phonation of the two groups. In sustained phonation of soprano classical singing students, F3 was formed around 3,000Hz, which was approx. 400Hz higher than a normal level. At spectral domain, H_E rose as pitch increased in both the groups. In other words, although the L/H ratio decreased in both the groups, the ratio decreased in more vowels and pitches of soprano classical singing students than those of general people.
Third, the most distinct statistical difference in formant domain between sustained phonation and classical vocalization of soprano classical singing students was F3. F3 was formed in a higher level of formant domain for classical vocalization. However, there was no difference in the energy of F3dB for singer’s formant depending on the phonation method. H_E of spectral domain rose as pitch increased in all phonation methods. Thus, the L/H ratio also decreased, and there was no significant difference depending on the phonation method.
In sum, although the change in F3 of soprano classical singing students was high for classical vocalization, F3 also changed for sustained phonation due to adjustment of larynx position by the influence of voice training. It is thought that, upon soprano classical singing students’ classical vocalization containing vibrato, the increase of vocal effort through homogeneous tone and vocal tract adjustment would lead to reduction in the L/H ratio as in sustained phonation.