Modeling and Visualizing Tonality in North Indian Classical Music

North Indian classical music (NICM) is based on raag, a melodic structure within which musicians improvise. Raags define hierarchical pitch relationships that can be described as tonal. The study of tonality in raag music may help to elucidate whether a cross-culturally valid cognitive model of tonal perception exists. We describe a basic model of tonality in raag music based on pitch-class distributions. We derive visualizations of tonal raag spaces based on self-organizing maps trained on pitch-class distributions calculated on actual performances, as well theoretically derived maps. We discuss implications of the theory and visualizations, as well as anticipated empirical verifications of the model.