
Musical Scales
Musical scales in Carnatic
music are generally assumed to be the skeleton structure for the melodic
entity viz., Raga. A musical scale is created by the permutation and
combination of notes rendered in a particular sequence in ascent
(Arohana) and descent (Avarohana). In Carnatic music, over 7.2
million scales are theoretically possible (reference Sangeeta Chandrikai
of Manikka Mudaliar). Generally, the terms scale and raga are
considered interchangeable. In fact a raga has a scale to give it a
structural form. But a scale alone does not become a raga.
Parent Scales 
Melakartas
In Carnatic music there are seventytwo
parent scales (Melakarta). This concept was conceived by Venkatamakhi in the
17th century, thus paving way for a scientific and logical melodic setup.
Before we learn about the 72melakartas, we must figure out the various
combinations of swaras that are possible.
The first tetrachord,
called the Poorvanga, comprises the first four notes, Sa, Ri, Ga and
Ma. And the second tetrachord, namely the Uttaranga comprises the
remaining notes  Pa, Dha, Ni and Sa (of the next octave).
Possible combinations of swaras
Combinations of Ri
and Ga 
Combinations of Dha
and Ni 
Ri 1 with Ga 1 
Dha 1 with Ni 1 
Ri 1 with Ga 2

Dha 1 with Ni 2 
Ri 1 with Ga 3 
Dha 1 with Ni 3 
Ri 2 with Ga 2

Dha 2 with Ni 2 
Ri 2 with Ga 3 
Dha 2 with Ni 3 
Ri 3 with Ga 3 
Dha 3 with Ni 3 
It should be noted that Ri
2 cannot combine with Ga 1 since their frequencies are the same.
Similarly, Ri 3 cannot combine with Ga 1 or Ga 2 since its frequency
is higher than and equal to those notes respectively. The same goes for Dha 2
 Ni 1 and Dha 3  Ni 1 / Ni 2.
Key to the seventytwo
Melakarta scheme

Since we have two varieties of Madhyama, the
first and logical division is based on it. Thus, the first 36 melas of the
melakarta have the perfect fourth, Suddha Madhyama, i.e. (Ma 1). In
the next 36, the fourth perfect is augmented or raised a bit to give
us the second variety of Ma, i.e., Prati Madhyama (Ma 2).

Each of the six melas in any given Chakra has the
same set of notes in the first
tetrachord,
the
Poorvanga. Since Sa is a
constant and Ma is predetermined, the remaining notes Ri and Ga change in
the order that we saw earlier (refer Possible combination of swaras). So
all the melas in the first Chakra have the first combination of Ri
and Ga, i.e. Ri 1 and Ga 1, the second Chakra Ri 1 and Ga 2, the third, Ri
1 and Ga 3 and so on.

The notes of the second tetrachord, the
Uttaranga, change for every mela of the particular Chakra. Now again,
Pa and Sa are the constants. The variables, Dha and Ni change in the same
order as given in the table, 'Possible combination of swaras'. Thus the
first melas of all the Chakras have
Dha 1 and Ni 1, the second, Dha 1 and Ni 2, the third, Dha 1 and Ni 3 and so
on.

The same procedure is repeated for the
second set of 36 melas. Thus the swaras of each of the melas in the first
Chakra correspond to that of the seventh Chakra with the exception of Ma,
which becomes Ma 2. Similarly, the melas of the second Chakra correspond
to the eighth, the third to the ninth and so forth.
The above concept can easily be illustrated
with an example. The
29th mela (i.e., the fifth mela of the fifth Chakra),
Dheerasankarabharanam uses Sa, Ri 2, Ga 3 (the fifth combination of Ri
and Ga), Mi 1 (being the Ma for the first 36 melas), Pa, Dha 2, Ni 3 (again
the fifth combination of Dha and Ni) and Sa in a straight sequence in ascent.
The exact reverse is rendered in the descent. In Western music, if the tonic
note Sa were to be taken as C, the rest of the notes would be D, E, F, G, A,
B and C in both directions. This is the Major scale in Cpitch.
(Refer Melakarta Chart)
Each of the seventytwo melakartas has been
given specific names for identification. This nomenclature is credited to
Govinda, the author of Sangraha Choodamani in 18th century AD. A
special formula devised by Venkatamakhi helps one remember the names of the
72melakatas. This formula in Sanskrit is known as Katapayadi sankhya.
All the other ragas are derivatives of the melakarta (which is why they are
known as the Parent scales), thus paving the way for a scientific
construction of the Carnatic music Raga system. It should be however
noted that, most of the seventytwo parent scales have emerged as ragas
today, though some existed even before this system was developed.
