Scores, Programs, and Time Representation: The Sheet Object in OpenMusic

Current computer-music systems deal with complex processes related to heterogeneous musical contents and information. In particular, the objects involved in music composition correspond to various temporal paradigms and representations. For instance, contemporary music composers frequently deal with time durations, or even directly with the continuous aspects of sound structures, instead of (or in relation to) a traditional pulsed-time representation. In these cases, however, continuous musical material must generally be associated with discrete and symbolic structures to allow for their meaningful representation (Boulez 1987). The score is a general framework for music writing in which this integration of musical material and the related issues of time representations should be carefully considered. Regardless of whether it concerns instrumental or electro-acoustic music, this document is of major importance as a formal support and a preferred place for musicians to write, read, and think about music. In this article, we focus on this notion of the score in computer-aided composition (CAC) through a presentation of related work in the visual programming environment OpenMusic (Agon 1998; Assayag et al. 1999). We introduce a new object recently created in OpenMusic: the sheet. This new object gathers results of CAC experiments and research concerning the relations between programs and score representations, the integration of sound and signal processing in compositional processes, the mixing of heterogeneous temporal systems, and the general visual representation of time structures in music notation. The sheet editor allows for accurate rhythmic notation while integrating specific features such as the support for new types of musical objects and programming tools. After a brief discussion of the question of the score in computer music composition, we present previous attempts at combining programs and scores