Shruti.

Shruti comes from sanskrit word “Shru” which means listening.The smallest interval of pitch that human ear can detect.In a Saptak there are 22 Shrutis.They are as follows:Sa-4,Re-3,Ga-2,Ma-4,Pa-4,Dh-3 and Ni-2.From these 22 Shrutis,only 12 are selected to be 7 Shudh Swars and 5 Vikrit Swars(komal and teevr).In a Saptak ,from any Swar to a difference of 10th Shruthi the Swar which comes is known as the Madhyam of Mool Swar(ie Major Sur).It is also known as “Shadaj Madhyam Samvad”or “Shadaj Madhyam Bhaav”.In the same way from any swar of the saptak ,the swar which comes after the diffrence of 14 shruthi is known as “Shadaj Pancham Samvad”or “Shadaj Pancham Bhaav”.In Shudh swar saptak the combination Sa Pa,Re Dh,Ga Ni ,are of “Shadaj Pancham Bhaav”.The combination of Sa Ma,Re Pa ,are of “Shadaj Madhyam Samvad”.Vadi Samvadi Swar are decided on the basis of this.