Intonation Analysis of Rāgas in Carnatic Music

Abstract

Intonation is a fundamental music concept that has a special relevance in Indian art music. It is characteristic of a rga and key to the musical expression of the artist. Describing intonation is of importance to several music information retrieval tasks such as developing similarity measures based on rgas and artists. In this paper, we first assess rga intonation qualitatively by analysing varṇaṁs, a particular form of Carnatic music compositions. We then approach the task of automatically obtaining a compact representation of the intonation of a recording from its pitch track. We propose two approaches based on the parametrization of pitch-value distributions: performance pitch histograms, and context-based svara distributions obtained by categorizing pitch contours based on the melodic context. We evaluate both approaches on a large Carnatic music collection and discuss their merits and limitations. We finally go through different kinds of contextual information that can be obtained to further improve the two approaches.

Keywords:

• music information research
• Carnatic music
• histogram parametrization
• pitch analysis

Acknowledgments

We are very thankful to Prof. Hema Murthy and Ajay Srinivasamurthy for their help in analyzing varṇaṁs.

Notes

1 This Sanskrit word literally means colour, and varṇaṁs in Carnatic music are said to portray the colours of a rga.

2 Chiṭṭa svaras in Sanskrit literally means the svaras in the end.

3 The audio recordings and their features are available on request.

4 To be concise, we discuss only a few of them here.

5 Ga in Bgaḍa and Mhanaṁ correspond to a svarastna which is different from the one that Ga in bhgi and Śr correspond to.

6 These recordings are also derived from the CompMusic collection, some of which also are part of the sub-collection we chose for evaluation.

7 Valley is to be understood as the deepest point between two peaks.

8 This value is empirically chosen.

9 https://github.com/gopalkoduri/pypeaks

10 The implementations provided in Weka were used with default parameters.

11 URL: https://github.com/gopalkoduri/intonation

12 Kampita is one of the gamakas which means oscillation. It can mean anything between a vibrato on a svara and larger modulations involving different svaras.

This research was partly funded by the European Research Council under the European Union’s Seventh Framework Program, as part of the CompMusic project (ERC grant agreement 267583). J.S. acknowledges 2009-SGR-1434 from Generalitat de Catalunya, ICT-2011-8-318770 from the European Commission, JAEDOC069/2010 from CSIC, and European Social Funds.