Combining audio and symbolic representation in OpenMusic visual programming language : a multimedia model of Iannis Xenakis’ Nomos Alpha
Résumé
We present our implementation of Iannis Xenakis’ compositional process in the piece Nomos Alpha for cello (1965). This implementation has been realized in the visual programming language OpenMusic (Assayag et al. 1999) by following the composer’s indications provided in his Formalized Music (Xenakis, 1992). It clearly shows the music-theoretical properties of the Fibonacci process according to which the different sound complexes are organized in the piece and the underlying formal model based on the group of rotations of the cube in the space. The model has both a pedagogical and a musicological interest for it enables the analyst to visualize the geometrical transformations used by the composer and to test the validity of the segmentation process and the singularity of some composer’s choices. Moreover, the implementation combines the audio and the symbolic representation, so that the listener can easily switch between the actual sound complexes and their logical organization inside of the piece. Finally, the model enables to change the initial conditions, as originally suggested in the composer’s sketches, and to obtain several instances of the piece, all sharing the same stylistic properties of the published musical score.