Traditionally, Indian musicians have just seven swaras/notes with short names: sa, re, ga, ma, pa, dha, ni, which they collectively refer to as saptank or saptaka.
The word is found in the Vedic literature, particularly the Samaveda, where it means accent and tone, or a musical note, depending on the context.
[7][8] The concept of a svara is found in Chapter 28 of the text Nāṭya Śāstra, estimated to have been completed between 200 BCE to 200 CE.
tatra svarāḥ – ṣaḍjaśca ṛṣabhaścaiva gāndhāro madhyamastathā । pañcamo dhaivataścaiva saptamo'tha niṣādavān ॥21॥ Natya Shastra – 28.21[13][9]This text contains the modern names: [Here are the] swaras - Shadaj, Rishabha, Gandhara, Madhyama, Panchama, Dhaivata, [and seventh] Nishada.
[14] The seven svaras of the saptak are the fundamentals of heptatonic scales or melakarta ragas and thaats in Carnatic and Hindustani classical music.
[15] The svaras of the sargam are often learnt in abbreviated form: sā, ri (Carnatic) or re (Hindustani), ga, ma, pa, dha, ni.
[2][3] Sage Matanga made a very important statement in his Brihaddeshi some 1500 years ago that:i.e. Shadaj, Rishabh, Gandhar, ... (and their utterance) are not the real svaras but their pronunciation in the form of aa-kar, i-kaar, u-kaar ... are the real form of the svaras.
So basically the translation is : The absolute frequencies for all svaras are variable, and are determined relative to the saptak or octave.
According to the music scholars of the distant past, the śruti is generally understood as a microtone besides veda and an ear.
In the context of advanced music, a śruti is the smallest gradation of pitch that a human ear can detect and a singer or instrument can produce.
The ancient Sanskrit text Natya Shastra by Bharata identifies and discusses twenty two shruti and seven shuddha and two vikrita svara.
The following quote explains it all:Bharata also makes some unscientific and unacceptable observations ignoring practically proven truths like samvaad (samvaada/ संवाद) or consonance of ma-ni, re-dha, re-pa and ga-ni as each of these svara pairs do not have equal number of shrutis to establish samvaad.
In reality, the above-mentioned pairs DO create samvaad or consonances which Bharata did not recognize for unknown reasons.
None of the musicologists give in writing the 'practical basis' or technique of ascertaining the ideal tonal gap between the note pairs like saa-re, re-ga, ga-ma, ma-pa, pa-dha, dha-ni, ni-saa* (taar saa) until Sangeet Paarijat of Ahobal (c. 1650).
The svara studies in ancient Sanskrit texts include the musical gamut and its tuning, categories of melodic models and the raga compositions.
Most of the practicing musicians knew very well that all the tuneful tones of seven notes could be discovered with the help of the theory of samvaad, in which saa-saa* (*means upper octave), saa-ma and saa-pa play the most crucial role.
In the Carnatic system however, the beginner exercises are sung in the raga Mayamalavagowla, which corresponds to the Western Double harmonic scale.
If a svara is not natural (shuddha), a line below a letter indicates that it is flat (komal) and an acute accent above indicates that it is sharp (tīvra, 'intense').
For example, r̥ṣabham has the three ascending variants "ra", "ri" and "ru", being respectively 1, 2 and 3 semitones above the tonic note, ṣaḍjam.