Stellar acoustics as input for music composition

Abstract

Background in acoustics. Variable stars show light variations due to internal acoustic waves. There are strong physical mathematical parallels between stellar behaviour and musical instruments: the basic principles underlying their "overtone" frequencies are identical. However, "stellar instruments" have many characteristics that make their sounds different from ordinary musical instruments. Background in theory/composition. Many composers have incorporated inharmonic spectra into their music. Computer technology now enables us to control inharmonic sound processes and deal with associated theoretical implications. Drawing stellar acoustics into the orbit of music fits in well with this trend in compositional practice. Aims. Our main aim is to demonstrate that sounds designed according to the principles of stellar physics and the nature of the processes inside stars can be used as a new basis for music composition, theoretical reasoning, and aesthetic evaluation. Main contribution. Both cosmic and musical events are determined by the temporal and hierarchical order of events, states and processes. Acoustic models of variable stars predict unusual patterns of "overtones" and variations in these patterns as the stars evolve. Due to the enormous size of stars, their oscillatory frequencies are orders of magnitudes lower than the audible range; therefore we should transpose those oscillations to the range of human hearing. However, the frequency range of possible stellar oscillations is much wider than the musical range, indicating a need for nesting points. These questions provide an interesting starting point for a cosmically inspired music theory. We developed a C-sound based computer application, to make the compositional experiments manageable. Implications. In our research, we combine scientific and artistic approaches and ways of thinking. Astrophysicists can investigate the special modes of vibration in stars of diverse size and inner structure, present possible sound sets that "celestial instruments" might offer, and provide information on their acoustic spectra. Composers can then scrutinize the audible features of these sonances, their behavior in diverse musical contexts, their aptness for creating tonal tensions, and their suitability for creating expressive musical structures. These points are illustrated with reference to the authors' Stellar Music No. 1.