Overview

This chapter is intended to give a glimpse into ways to put some of the techniques and concepts introduced in the previous chapters into practice. There are three short case studies. The first case study illustrates how one could start by using a combinatorial mechanism to produce musical material and use a rule base to give form to this material. The second case study illustrates a somewhat reverse process. Here a formal grammar is used first to generate melodic forms whose content is determined later by means of distribution functions.

Both case studies employ mechanisms that act upon sets of basic musical elements in order to generate musical content and rules to shape musical form. This is indeed standard practice in contemporary composition and it is ubiquitous in most algorithmic or automated composition systems. There is, however, one missing aspect here for which computers can provide excellent assistance, but it has been largely overlooked by composers: the definition of musical elements, or building blocks.

The third case study addresses this by proposing a method for deriving pitch systems from the inner structure of human vocal sounds. Here the computer is used both to dissect sound recordings in order to extract pitch information from them, and to synthesise this pitch information in order to monitor the process. In this case, synthesis can also play an active part in composition, as nowadays it is very common to compose with coexisting synthesised and acoustic sounds.

7.1 From content to form

The following...