Shruti (music)

The shruti or śruti [ɕrʊtɪ] is the smallest interval of pitch that the human ear can detect and a singer or musical instrument can produce. The concept is found in ancient and medieval Sanskrit texts such as the Natya Shastra, the Dattilam, the Brihaddeshi, and the Sangita Ratnakara. Chandogya Upanishad speaks of the division of the octave in 22 parts.

The swara differs from the shruti: the shruti is the smallest gradation of pitch available, while a swara is the selected pitches from which the musician constructs the scales, melodies and ragas. The Natya Shastra identifies and discusses twenty-two shruti and seven swara per octave.

It has been used in several contexts throughout the history of Indian music. Recent research has more precisely defined the term shruti, its difference from nada and swara, and identified positions on a string to play 22 shrutis.