Differences between brass instruments arising from variations in brassiness due to nonlinear propagation

Joël Gilbert (1) , Murray Campbell (2) , Arnold Myers (2) , Bob Pyle (2)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans
2 Edin. - University of Edinburgh

The brightness of the sound generated by brass instruments at high dynamic level is mainly due to the essential nonlinearity of the wave propagation in the pipe. The bright instruments such as the trumpet and the trombone are different from more mellow brass instruments such as saxhorns or flugelhorns. The bright instruments have an almost cylindrical pipe segment just downstream of the mouthpiece. The conical bore of the saxhorns in this region implies a faster decay of the wave which reduces the nonlinear wave steepening. To investigate the differences between the brassiness of different instruments, crescendos were played using five different brass instruments representing the various brasswind families. A characteristic spectral enrichment parameter was extracted for each recorded sound. In parallel, a brassiness parameter was derived from weakly nonlinear 1D propagation theory. This parameter was calculated for each brass instrument from its bore geometry. The spectral enrichment parameter is found to be a monotonic increasing function of the brassiness parameter. This makes the brassiness parameter a useful tool to classify brass instruments from the point of view of their ability to play “cuivrés” or brassy sounds.

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

Joël Gilbert, Murray Campbell, Arnold Myers, Bob Pyle. Differences between brass instruments arising from variations in brassiness due to nonlinear propagation. International Symposium on Musical Acoustics (ISMA), Sep 2007, Barcelone, Spain. ⟨hal-00475561⟩