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

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.