Evaluation of Acoustic Parameters for Angulimala Sutta using Voiced to Unvoiced Ration and Vowel Distribution

Pirith is believed as a protective doctrine preached by the Load Buddha in Pali language. The aim of this study is to analyze acoustic properties of Pirith using computer-aided methods and identify special characteristics and patterns. In this study, two methods were used to identify special characteristics of Angulimala Sutta. First method calculates voiced to unvoiced ratio using zero crossing rate and energy content associated with the acoustic signal while second method recognizes vowel distribution using first and second formant frequencies. Results of the first method indicates approximately 96% of frames are voiced while the second method suggests approximately of vowels concentrate in the square region of  F₁, 0~1500 Hz and F₂, 0~1500 Hz demonstrating when chanting the Angulimala sutta most of the time the tongue height is low positioned in back levels while lips shaped unrounded.