“…The research in the theoretical part of acoustic investigations was based on general knowledge about the physics of sound propagation (diffraction and absorption). A number of studies on formant tuning and singer's formant in western operatic vocal, including those by L. Dmitriev, and A. Kiselev [9], H. K. Shutte, and R. Miller [20], T. Millhouse, F. Clermont, and P. J. Davis [14], (especially) J. Sundberg [21; 22; 23; 24; 25; 26; 27], and others, were reviewed. The academic writings in the field of acoustic analyses of nonwestern singing by G. Chrysochoidis, D. Delviniotis, G. Kouroupetroglou, and S. Theodoridis [7], R. Sengupta [18], N. A. Joshi, and M. A. Raju [12], R. Ambrazevičius [1; 2; 3; 4], R. Budrys [4], A. Johnson, J. Sundberg, and H. Wilbrand [11], G. Kovačić, P. Boersma, and H. Domitrović [13] have to be admitted here as well.…”