7 – Indian Music Systems – Notes

Western music system divides an octave into 12 ‘semitones’, each with a 100-cent measure. So, an octave is 1200 cents. Currently, Indian systems too, use the same approach. However, the old Indian systems, starting during the Vedic period and continuing with Bharata in the Natya Sastra, recognised 22 shrutis or notes between an octave, the interval between two nearest shrutis being seen as the smallest interval (around 54.5 cents) that a human ear can recognise. The shruti system has fallen into disuse in India. As said before, Indian systems also now use the 12-division system rather than the 22-division system. [This does not mean that Indian musicians do not use microtones (frequencies between the recognised note frequencies) in their rendering. They regularly do, and some ragas use extra flat and extra sharp notes. In fact, some of the notes are seen to lie within a range of frequencies (approximately 20 cents around the frequency of the note in the 12-note system) and musicians can render a particular note anywhere in this range (in addition to occasionally using frequencies towards the middle of recognised semitones) depending on the mood of the song.

But this cannot be equated with the old shruti system. However, the following system is widely recognised (see picture): The tonic (Sa) and the dominant note (Pa) are seen as having only a single tone each. The other ten notes have a frequency range (as we said before) of around 20 cents. The lower end and the upper end of this range can be seen as separate notes and hence we can get 10*2 = 20 + 2 = 22 notes or shrutis. It should be noted that different musicians use different points within the range of these notes depending on the raga and the mood].