Shruti (music)

Indian Music
Indian classical music
Carnatic music
Hindustani music
Core Concepts
Shruti · Swara · Alankar · Rāga · Tāla

The shruti (or "sruti" Sanskrit: श्रुति, Kannada: ಶ್ರುತಿ,Malayalam: ശ്രുതി Telugu: శ్రుతి, Tamil: சுருதி) is a Sanskrit term used in several contexts throughout the history of the Indian music. A shruti is the smallest interval of pitch the ear can detect.

Contents

Contexts

To know the real meaning of shruti, it is important to know the various contexts in the history of Indian music where the term is used.[1]

Ancient period: Grama system

Bharata uses shruti to mean "the interval between two notes such that the difference between them is perceptible". He formulates jatis, which are classes of melodic structures. They are further grouped into two gramas – shadja-grama and madhyama-grama. The notes (svaras) are separated by intervals, which are measured in terms of shrutis.

The shadja-grama is given by the following division: Sa of four shrutis, Ri of three shrutis, Ga of two shrutis, Ma of four shrutis, Pa of four shrutis, Da of three shrutis and Ni of two shrutis. Bharata also describes an experiment to obtain the correct physical configuration of shruti in shadja grama, Sarana Chatushtai.

The madhyama-grama is the same, but the panchama (Pa) has to be diminished by one shruti. That is, the panchama of madhyama-grama is lower than that of shadja-grama by one shruti according to Bharata. Shruti is only mentioned as a perceptual measure in the music of Bharata's time.

Shruti is better understood with the following explanation. In both the gramas, Ri is three shrutis away from Sa – there are three perceptible intervals between Sa and Ri. The third of these is called trishruti rishaba (Ri). Likewise, the second interval is called dvishruti rishabha, and the first ekashruti rishabha.

Notes at 9 and 13 shrutis from each other are mutually samvādi (consonant). The notes that are at the distance of 2 and 20 shrutis are mutually vivādi (dissonant). The remaining ones, at the distance between 2 and 20 shrutis, are called anuvādi (assonant).

The shruti table below shows the mathematical ratios considered to correspond to the system described by Bharata and Dattila, along with the comparable notes in common Western 12-TET tuning, and the names of the 22 shrutis provided by Śārñgadeva.

Shrutis 12-TET Notes
Name Ratio Cents Frequency
(Hz)
Name Frequency
(Hz)
Kṣobhinī 1 0 261.6256 C 261.6256
Tīvrā 256/243 90 275.6220 C 277.1826
Kumudvatī 16/15 112 279.0673
Mandā 10/9 182 290.6951 D 293.6648
Chandovatī 9/8 203 294.3288
Dayāvatī 32/27 294 310.0747 D 311.1270
Ranjanī 6/5 316 313.9507
Raktikā 5/4 386 327.0319 E 329.6275
Raudrī 81/64 407 331.1198
Krodhā 4/3 498 348.8341 F 349.2282
Vajrikā 27/20 519 353.1945
Prasāriṇī 45/32 590 367.9109 F 369.9944
Prīti 729/512 612 372.5098
Mārjanī 3/2 702 392.4383 G 391.9954
Kṣiti 128/81 792 413.4330 G 415.3047
Raktā 8/5 814 418.6009
Sandīpanī 5/3 884 436.0426 A 440.0000
Ālāpinī 27/16 906 441.4931
Madantī 16/9 996 465.1121 A 466.1638
Rohiṇī 9/5 1017 470.9260
Ramyā 15/8 1088 490.5479 B 493.8833
Ugrā 243/128 1110 496.6798
Kṣobhinī 2 1200 523.2511 C 523.2511

Ancient treatises on Indian classical music and performing arts

Medieval period: Mela system

By the time Venkatamakhi formulated the melakarta ("mela") system, the grama system was no longer in use. Unlike the grama system, the mela system uses the same starting swara. it forms the scales by varying the intervals of the subsequent swaras, and does not specify a fixed interval for a swara in terms of shrutis. For example, the intervals of kakali-nishada and shuddha-madhyama would vary depending on the dhaivata and the gandhara that precede them, respectively. The interval of kakali-nishada would be of three different shruti values depending on whether shuddha, panca-sruti or shat-shruti-dhaivata preceded it. Thus shruti as a measure of interval is not fully utilized in the mela system.

Modern period: Controversy

The mela system still prevails. The term shruti in current practice of Carnatic music, has several meanings.[2] It is used by musicians in several contexts. For instance, the tamil term, "Oru kattai sruti" would mean that the tonic is set to the pitch C or the first key. The telugu term, "Sruti chesuko (శ్రుతి చేసుకో)" is a way to correspond with the accompanying artists to tune their instruments.

The term has also undergone a gross misunderstanding. In certain raagas, due to inflexions or gamakas on few of those 12 notes, the listeners perceive a sharpened or flattened version of an existing note.[3] Few scholars have attempted to fit such perceived new tones into the non-contextual Bharata's 22 shrutis, which lead to confusion and controversy over 22 shrutis. It was also wrongly attributed to Bharata, who has proposed shruti in a completely different context.

There is scientific evidence which shows that these intermediate tones perceived in the contemporary rendition of a raaga does not hint at the existence of 22 shrutis. The number 22 is of no practical significance in the current performance of Carnatic and Hindustani music traditions. The phenomenon of intermediate tones is pursued as an active area of research in Indian Musicology, which says the number of perceptible intermediate tones may be less or even much more than 22.[3] N. Ramanathan, a musicologist points it out and says that the idea of 22 shrutis is applicable only to the music system of Bharata's time.

References

  1. ^ Ramanathan, N. Sruti in Ancient, Medieval and Modern Contexts, an article from musicresearch.in
  2. ^ Krishnaswamy A. Inflexions and Microtonality in South Indian Classical Music. Frontiers of Research on Speech and Music, 2004.
  3. ^ a b Krishnaswamy A. On the twelve basic intervals in South Indian classical music. AUDIO ENGINEERING SOCIETY. 2003

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