Speech Communication & Speech Analysis

A Dissertation submitted by
Karuna Nagarajan under the guidance of J Chandrashekaran, Heisnam Jina Devi,
N V C Swamy & H R Nagendra
 
for the partial fulfillment of Masters in Yogic Science
Swami Vivekananda Yoga Anusandhana Samsthana
Prashanthi Kuteeram, Jigani

Abstract: Musical notes have played an important role in the growth of human culture and civilization. India has a rich heritage of music from the time of the Samaveda. There is a rich literature about music, its techniques and its rendition. But there is hardly any information about the sound aspects of musical notes.

The objective of the study is to investigate the spectral & frequency characteristics of the musical note, in the ascending scale (Arohana), when they are subjected to the influence of gamaka. The musical notes are in the standard Mayamayava Raga of Carnatic classical music.

The results show the variation pattern of the frequencies both fundamental & sub-harmonics during the smooth transition from one note to the other in ascending scale.

All conclusions are based upon the study of the waveforms, spectra & sonograms for three male voices & three female voices. The methodology adopted was the use of Sound forge software version 4.5.

It is concluded from the study, that the male voice displays less variation of frequencies during gamaka than the female voice. It is also seen with gamaka, the seven notes appear like a staircase with alternate note serving as the rise & the step.

Summary & Conclusion: This is the first study of its kind and hence the conclusions drawn are only indicative. The musical notes which have been used for analysis are periodic in nature and hence lend themselves to a spectral analysis easily.

Usually in the case of flat notes, the frequency of the signal is constant with time. But, in the case of gamaka the sonograms indicate variation with respect to time, which helps us in determining the precise locations of gamaka.

The notes with gamaka appear to form a staircase with the alternate notes representing a rise and the step, thus justifying the use of the technical word (Arohana).

The analysis shows that the female voices exhibit a more predominant gamaka than the male voices. This can be attributed to the fact that the deeper male voices has a rich timbre which plays the same role as the gamaka itself. On the other hand the female voice with a shallower timbre has to emphasise gamaka more. This is clearly brought out by the sonograms.

When the male & the female voice moves over the ascending musical scale, the fundamental frequency continously increases as expected. This is also reflected in our study.