This article introduces the concept of real-time composition and composition as a “dispositif” in the sense of Foucault and Deleuze, defining it as a heterogeneous ensemble of pieces that together form an apparatus. The introduction situates the dispositif in the context of cultural developments, most notably its slow but steady shift away from textualization in digital media. As musicians are adapting to ensuing cultural and, above all, economic changes, new musical forms emerge that rely to a lesser degree on fully notated scores, such as “comprovisation” or laptop performance. Antithetically, the computer also allows the creation of “authorless” notated scores in real time to be sight-read by capable musicians—a practice for which special software has been developed in recent years. Because these scores are not meant to be kept and distributed, they are ephemeral and, therefore, disposable. Three examples by the author are given to illustrate the interwovenness of this approach, where carefully selected narratives and dramaturgies make up for the inherent unpredictability of the outcome.

We present an algorithm, instantiated in a freeware application called MeanTimes, that permits the parameterized production and transformation of a hierarchy of well-formed rhythms. Each “higher” rhythmic level fills in the gaps of all “lower” levels, and up to six such levels can be simultaneously sounded. MeanTimes has a slider enabling continuous variation of the ratios of the intervals between the beats (onsets) of the lowest level. This consequently changes—in a straightforward manner—the evenness of this level; it also changes—in a more complex, but still highly patterned manner—the evennesses of all higher levels. This specific parameter, and others used in MeanTimes, are novel: We describe their mathematical formulation, demonstrate their utility for generating rhythms, and show how they differ from those typically used for pitch-based scales. Some of the compositional possibilities continue the tradition of Cowell and Nancarrow, proceeding further into metahuman performance, and have perceptual and cognitive implications that deserve further attention.

This article describes the use of second-order all-pass filters as components in a feedback network, with parameters made time varying to enable effects such as phase distortion in a generative audio system. The term “audio” is used here to distinguish from generative “music” systems, emphasizing the strong coupling between processes governing the production of high-level music and lower-level audio. The classical time-invariant implementation of an all-pass filter is subject to issues of instability that can arise when time-invariant filter parameters are allowed to vary over time. These instabilities are examined, along with the adoption of a power-preserving rotation matrix formulation of the all-pass filter to ensure stability and ultimately an improved synthesis for a generative audio system.