Non-uniform time-scaling of Carnatic music transients

TL;DR

This paper investigates how tempo changes affect gamakas in Carnatic music, proposing a non-uniform time-scaling method that preserves transient durations, supported by theoretical analysis and listening tests.

Contribution

It introduces a novel non-uniform time-scaling approach for Carnatic music that maintains the duration of transients during tempo modifications.

Findings

Transients' durations are largely unaffected by tempo changes.

Non-uniform time-scaling aligns with perceptual qualities of Carnatic music.

Listening tests confirm the effectiveness of the proposed method.

Abstract

Gamakas are an integral aspect of Carnatic Music, a form of classical music prevalent in South India. They are used in ragas, which may be seen as melodic scales and/or a set of characteristic melodic phrases. Gamakas exhibit continuous pitch variation often spanning several semitones. In this paper, we study how gamakas scale with tempo and propose a novel approach to change the tempo of Carnatic music pieces. The music signal is viewed as consisting of constant-pitch segments and transients. The transients show continuous pitch variation and we consider their analyses from a theoretical stand-point. We next observe the non-uniform ratios of time-scaling of constant-pitch segments, transients and silence in excerpts from nine concert renditions of varnams in six ragas. The results indicate that the changing tempo of Carnatic music does not change the duration of transients significantly. We report listening tests on our algorithm to slow down Carnatic music that is consistent with this observation.