In this paper, I contend that expressive timing and thematic transformation represent interrelated improvisational processes that are coordinated in performances of jazz standards. I connect these techniques to recent work on jazz ontology and referents, arguing that the ambiguous relationships between these transformational categories is the result of the ontological flexibility of jazz tune melodies. I ultimately argue that both techniques become involved in an ongoing give-and-take as the improvisational process unfolds.

In this article, we analyze microtiming and tempo variability in the music of five renowned rock drummers: Ringo Starr, Mitch Mitchell, Stewart Copeland, Phil Rudd, and Meg White. Using the applications Moises and Sonic Visualiser, we isolated the drum stems of 79 studio and live recordings and determined exact quarter-note positions in backbeat patterns.