When liner-note writers, musicians, and critics write about twentieth-century music, it is not contours or set classes that they typically point to but, more often, recurrent, aurally salient gestalts -- phenomena like "pointillistic staccato figures" (Rosen 1997) and "loud sustained chordal tremolos" (Flynn 1975). By focusing on such patterns, these writers are able to speak to wide audiences; they also gain means for simplifying and grappling with twentieth-century music's information-rich surfaces -- no small feat.

In academic discourse, patterns like these are also featured (e.g., MacKay 2009); overall, however, they are overlooked and undervalued. If unfortunate, this neglect is understandable: first, because these patterns have rarely been used or explicitly targeted in mainstream analysis, their availability and utility has been unclear. Second, because the patterns have not been formalized, they are discursively weak. Last, because the patterns have typically been paired with inefficient, confusing methodologies, they have appeared clumsy and second-rate as analytical objects.

Were these phenomena taken more seriously, exciting new interpretations could be entertained in the analytic community; clearly, however, the patterns need to be justified and equipped with better discursive means. In this paper I therefore highlight the patterns, formalize them as instances of a pattern type that I call the "Mode of Activity," supply them with improved definitional methods, and emphasize their potential via case studies from Luciano Berio's Sequenzas -- a formidable repertoire that demonstrates these patterns' worth.