An analysis of the compositional techniques in John Chowning's Stria

This article describes an analytic study of the process used by John Chowning for the composition of Stria. This article is intended to complete the description of the compositional process given in a previous work (Meneghini 2003), largely restated by Bossis in a subsequent paper (Bossis 2005). Stria was composed in 1977 and was fully generated by means of computer algorithms (Chowning 1977c) and the corresponding input files (Chowning 1977a,b): all the parameters of the sounds generated in Stria are determined and calculated by these algorithms on the basis of specific mathematical rules and of numerical parameters chosen by Mr. Chowning as input for the programs. For this reason, an accurate analysis of these algorithms is-fundamental for a complete comprehension of the compositional process. This analysis has three degrees of interest: at first, it enables a study of the composer's intentions regarding the piece's characteristics. Secondly, it complements the comprehension of Stria obtainable from listening with analytic data on the properties of the sounds. Finally, it provides information on the characteristics of the piece that can be used for the re-writing of the algorithms and for the analysis and re-synthesis of the piece (Baudouin 2007; Dahan 2007). The work described in this article began in 2002, and it started with the study of the programming language SAIL) used for the generation of the algorithms (Smith 1976; see also www.xidak.com/mainsail/ documentation_set_1630_html/docset.html), which was necessary for the understanding of the programs. The algorithms (Chowning 1977c) have been then carefully analyzed, line by line, to achieve a complete understanding on how the parameters of each sound generated in Stria are determined. Personal communication with the composer was indispensible for the interpretation of some of the procedures used, and for the understanding of Mr. Chowning's intentions related to programming choices. © 2007 Massachusetts Institute of Technology.