Does the elephant trumpet like a trumpet?

Joël Gilbert (1) , Jean-Pierre Dalmont (1) , Romain Potier (2)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans
2 Zoo de Beauval

Elephants produce a broad range of sounds from very low frequency rumbles to higher frequency trumpets. Trumpets are produced by a forceful expulsion of air through the trunk. Trumpets are mainly tonal sounds. Elephants tend to trumpet when they are highly stimulated and the quality of trumpeting varies with the context.Some elephant trumpeting sounds are very similar to a trumpet or a trombone sound especially when playing “brassy”. This kind of brassy sounds played at high level dynamic, are made of a lot harmonics as a consequence of the wave steepening in the bore. The wave steepening is a cumulative effect obtained during the nonlinear propagation along the internal bore. A parameter to judge the severity of the nonlinear steepening is the critical shock length distance associated to a given input pressure profile. When the length of the bore is comparable to this critical distance, highly distorted waves can be observed in the bore, and it is the case for brass instruments played at fortissimo level. The internal bore of the vocal system of the elephant, from the vocal folds to the open end radiating the sound - trunk end - is several meters long, like brass instruments. The vocal system is so long than the nonlinear steepening effect might be significant during elephant trumpeting. This hypothesis is discussed from elephant trumpet's signals, and estimated by comparison with human voice and brass musical instruments under playing conditions.

Mots clés: Acoustic; Nonlinear propagation; Elephant trumpet calls; Brassy sounds

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

Joël Gilbert, Jean-Pierre Dalmont, Romain Potier. Does the elephant trumpet like a trumpet?. 20th International Congress on Acoustics (ICA 2010), Aug 2013, Sydney, Australia. ⟨hal-00486978v2⟩