Assessing the Tuning of Sung Indian Classical Music

The issue of tuning in Indian classical music has been, historically, a matter of theoretical debate. In this paper, we study its contemporary practice in sung performances of Carnatic and Hindustani music following an empiric and quantitative approach. To do so, we select stable fundamental frequencies, estimated via a standard algorithm, and construct interval histograms from a pool of recordings. We then compare such histograms against the ones obtained for different music sources and against the theoretical values derived from 12-note just intonation and equal temperament. Our results evidence that the tunings in Carnatic and Hindustani music differ, the former tending to a just intonation system and the latter having much equal-tempered influences. Carnatic music also presents signs of a more continuous distribution of pitches. Further subdivisions of the octave are partially investigated, finding no strong evidence of them.