We discuss a time-frequency analysis of musical rhythm that reveals the underlying hierarchical structure of
percussion performance. The mathematical tools we employ are Gabor transforms (also known as short-time
Fourier transforms, or spectrograms) and the new technique of percussion scalograms.  We determine satisfactory parameters for
computing percussion scalograms as descriptors of musical rhythm. We use our tools to display the hierarchical
structure of rhythm within a variety of percussion performances. Our method can yield a symbolic score for a recorded
percussion performance, and how this score is hierarchically structured, which provides insight into the differences between
different musical styles. We also discuss an example relating to both rhythm and melody, and how they are both hierarchically
organized.