In my last post, I'd touched upon the theme of knowing Carnatic music, in order to appreciate it better. In this post, I'd like to explicate the math behind the theory of Carnatic music for the benefit of all those who are passionate about knowing Carnatic music.
Indian Carnatic music is a seemingly complex theory that has raaga & thaala as its cornerstones. A raaga is basically the melody(scale) and the thaala is basically the rhythm(beat). The seven basic notes (or Saptha Swaras) that comprise every raaga are Sa, Re, Ga, Ma, Pa, Dha & Ni. These could be thought of as the Carnatic music counterparts of Western music's Do, Re, Mi, Fa, So, La & Ti respectively. Henceforth, I shall use the term swara to refer to a musical note.
Whereas the swaras Sa and Pa are always fixed (meaning, they do not have sharp or flat variants), the swaras Re, Ga, Dha & Ni have three variants apiece & the swara Ma has two variants. The below illustration shows the different swaras as laid out on a musical keyboard's C-scale. Note that the swara R2 is the same as G1 & the swara R3 is the same as G2. Similarly, the swara D2 is the same as N1 & the swara D3 is the same as N2. For reasons of lack of space and easy understanding, the names of the swaras have been represented using their first letters alone.

The variants of the swaras R & G can be used to create 6 different combinations which are R1-G1, R1-G2, R1-G3, R2-G2, R2-G3 & R3-G3 respectively. Similarly, the variants of the swaras D & N can be used to create 6 different combinations, thereby resulting in 6*6=36 combinations for the 4 swaras R, G, D & N. These 36 combinations, when multiplied by the available two variants of the swara M, produces a total of 36*2=72 combinations, for all the available 5 variable swaras. These 72 combinations are referred to as the Melakartha raagas. Of them, the first 36 raagas that use the first variant of the swara M are called Shuddha-Madhyama raagas & the next (or last) 36 raagas that use the second variant of the swara M are called Prathi-Madhyama raagas.
Every raaga is a pattern of swaras and is defined by the way it flows from one swara to the other. The ascending pattern is called as aarohana & the descending pattern is called the avarohana. For the 72 Melakartha ragas, the aarohana & avarohana have the same swaras, meaning that the avarohana is just a simple reversal of the aarohana.
Though the basic Melakartha raagas are only 72 in number, Indian Carnatic music gives you the flexibility and freedom to experiment with the swaras and create as many raagas from them, by omitting one or more swaras (note that the swara S cannot be omitted). Another fine flexibility allowed is that these omissions can be done separately for the aarohana & the avarohana. i.e., any swara that is omitted in the aarohana can be included in the avarohana & vice-versa, thereby provisioning the gamut of raagas for futher extensibility.
Hmmm.. so, how do you feel? Having started to taste Carnatic music theory, feel like hogging more? Here's a goodie that I'd like to offer you to get started with practising all the theory. I've come up with a list of all the 72 Melakartha raagas along with their aarohanas & avarohanas. The best method to familiarise yourselves with these raagas would be by trying these swaras on a musical keyboard. The list of the 72 Melakartha raagas in PDF format, can be downloaded here.
In my future posts, I shall talk more about thaalas, popular composers, veterans, famous artistes, instrumental music & a lot more. As always, keep the comments & suggestions pouring in!