Visualizing Intertextual Form with Arc Diagrams: Contour and Schema-based Methods

The visualizations in Wattenberg's Shape of Song (2001) were based on pitch-string matching, but there are many other equivalence classes and similarity relations proposed by music research. This paper applies recent algorithms by Carter-Enyi (2016) and Carter-Enyi and Rabinovitch (2021) with the intention of making arc diagrams more effective for research and teaching. We first draw on Barber's intertextual analysis of Yoruba Oriki, in which tone language texts are circulated through various performances (Barber 1984). Intertextuality is exemplified through a 2018 composition by Nigerian composer Ayo Oluranti, then extended to Dizzy Gillespie's solo in his recording of "Blue Moon" (ca. 1952). Example visualizations are produced through an open-source implementation, ATAVizM, which brings together contour theory (Quinn 1997), schema theory (Gjerdingen 2007), and edit distance (Orpen and Huron 1992). Applications to the music of Bach and Mozart demonstrate that an African-centered analytical methodology has utility for music research at large. Computational music research can benefit from analytical approaches that draw upon humanistic theory and are applicable to a variety of musics.