Visualizing Music: Tonal Progressions and Distributions

This paper presents a music visualization tool that shows the tonal progression in, and tonal distribution of, a piece of music on Lerdahl’s two-dimensional tonal pitch space. The method segments a piece into uniform time slices, and determines the most likely key in each slice. It then generates the visualization by dynamically showing the sequence of keys as translucent, growing discs on the twodimensional plane. The frequency of a key is indicated by the size of its colored disc. Each color and position corresponds to a key, and related keys are shown in proximity with related colors. The visual result effectively presents the changing distribution of the keys employed. The proposed visualization is an improvement over more basic charting methods, such as histograms, and it maintains standards of information design in the form of added dimensionality, color, and animation. We show that the visualization is invariant under music transformations that preserve the piece’s identity. We conclude by illustrating how this method may be used to visually distinguish between tonal progression and distribution patterns in western classical versus Armenian folk music.