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Indian Classical Music And Its Scientific Significance
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notes, which are produced when a harmonium keys are pressed. In music an 'interval' is a very important quantity. An 'interval' shows the difference in pitch between two notes on a given scale. For this let us study the intervals on the key-board of a piano or a harmonium. The figure shows the frequency of the note produced by pressing a key. We can see here that if we press two neighbouring keys of piano, we obtain a small interval between two notes. Similarly, if we press two distant keys of a piano, we obtain a large interval between two notes. We can, therefore, easily conclude that the interval is determined by the difference between frequencies of two notes. But this is not the whole truth. Really speaking, the interval is determined by the ratio of frequencies. The intervals of the octave shown above, are determined as under.
This is only a model. Many such intervals can be determined on the basis of the ratio of different frequencies. Some such intervals are given special names in the western music. They are shown in the Table. These names belong to the western music but in the Indian classical music also, corresponding keys of a piano, their notes and the ratio of their frequencies are shown instead of their names.
Duration of interval
Name of the intervals
Symbol of the
Ratio of
Name of the notes
of notes
key of the
frequencies
piano E-F D-E C-D E-G
16/15 10/9 9/8 6/5 5/4 4/3
CF
1 Half-tone, Minor Second 2 Minor tone, Major second 3 Major tone 4 Minor third 5 Major third 6 Perfect fourth 7 Perfect fifth 8 Minor sixth 9 Major sixth 10 Minor seventh 11 Major seventh 12 Octave
mitt - fah ref . mit doसा - reरि mit - sola doसा - miग doसा - faम do FIT - solg mirt - do'n doसा - lau mit - re'f do II - till do WT - doʻHT
3/2
E-c
8/5 5/3
C-A E-d C-B
9/5
15/8
C-c"
2/1
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