| Yoga in Perception and Performance |
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Methodology
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The experimental procedure consists of thefollowing steps: (1) recording of the musical notes with the use of a sensitive microphone (2) digitizing the analog wave forms with the help of a computer using a sampling rate of 44100 per second (3) analyzing the digitized data toget information about the energy – frequency and frequency – time spectra and(4) identifying the predominant frequencies and formants. The procedure for recording was essentially the same as described earlier1. Here also,experts from outside institutions vetted the quality of the signals.
The recording was done for a total of ten male and female voices for both ascending and descending scales. Two inclusion criteria were used – the steadiness of the voice and the perfection of the notes. Based on these criteria, four voices were eliminated. The rest of the six voices, three male and three female were then used for analysis only forthe ascending scale since the variation of these voices for the ascending and the descending scales was hardly noticeable.
The ascending musical scale was that usedin Carnatic music based on Raga Mayamalavagowla.The number of musical notes available for study was 42, half for the male voicesand the other half for the female.
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Observations
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The wave forms for the seven musical notes for the six voices formed the raw data, which can be processed to yield the following information:
(a)Short time window patterns of the wave forms usually of 100 millis displaying the periodic nature of the signals.
(b) Energy – frequency spectra for all notes and voices displaying theenergy distribution among the various harmonics and sub harmonics.
(c)Frequency – time spectra for all cases complementing the energy – frequency spectra.
(d) Predominant frequencies and their sub harmonics for all cases.
The total number of figures arising out of the analysis, works out to 111, with 6 wave forms, 21 short time window patterns, 42 energy – frequency spectra and 42 frequency – time spectra. All conclusions drawn have been based on the analysis of all these figures. Only a few representative ones are given here.
The wave forms for a male voice are given in fig. 1 and those for a female voice in fig. 2. The 100 millisec window amplificationof the signal for “sa” is shown infig. 3 for a male and a female voice. The energy – frequency for the first fournotes for a male voice are given in fig. 4 - 7 and the same for a female voicefor the last three notes in fig. 8 -10.
The most important figures from the point of view of the analysis are the frequency – time spectra. The spectracorresponding to the fig. 4-10 are shown in fig. 11and 12. As mentioned earlier, these are only samples of the total information available. |
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