Spectrographic and Electroglottographic Findings of Religious Vocal Performers in Düzce Province of Turkey

Summary Objectives In the present study, the register phenomenon and spectral characteristics of vocal styles used by vocal performers in a Muslim community were investigated. Methods Electroglottography was performed on 17 subjects, whereas spectrography was performed on 18 subjects, and 16 of these subjects participated in both parts of the study. Results We observed that the participants used chest register in voice production and there was no change in this situation related to the increase in frequency. It was found that Western opera singers' formant cluster did not exist in their normal speech and performance voice spectrum. Generally, there were clear energy peaks at the 3- to 4-kHz spectral region in their performance voice, but this peak did not appear in the daily speech voice. Conclusions It was concluded that a bunched F3, F4, and F5 is a critical prerequisite in the production of a calling formant cluster. However, it was observed that in certain cases, this phenomenon was produced only with bunching of F4 and F5 or with an increased F4 energy level. Although an increase in F3 assists in the production of the calling formant cluster, the main source of the calling formant cluster was the decrease in F4 and F5 frequencies, and the main contribution came from F5, which was fairly decreased. Moreover, it was found that a decreased closed quotient value caused a raise in the relative level of calling formant cluster (Lcfc) value. In conclusion, our results indicate that the production of the calling formant cluster is based not only on vocal tract properties but also on glottal settings.