Elephant Trumpets, the Acoustics of

“Because trumpeting is often associated with intensely social events, expressing the very high level of excitement and importance of the event, it is not easy to ask elephants for trumpet calls!”

But that did not deter a research team at the Laboratoire d’Acoustique de l’Université du Maine, Le Mans, France (assisted by the Zoo de Beauval, Saint-Aignan) from collecting audio samples of elephants’ trumps in order to perform the first (?) scientific investigation into the acoustical complexities of their production.

“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.”

Elephant_Trump_FormulaThe team worked with mathematical formulae [see full paper for details] which might closely represent the acoustic phenomena occurring during trumpeting, and tested their relevance against recordings of two types of trumps – so-called ‘brassy’ and ‘non-brassy’.

“Elephant trumpet calls are powerful sounds having a rich harmonic structure, sounding like brassy sounds of musical instruments. Note that it is quite easy to imitate elephant trumpet calls with a trombone! To answer the speculative question about nonlinear propagation effects in trumpet calls, a first answer was obtained by estimating a realistic critical shock length distance xs: the shock length distance xs is comparable to the trunk length. It means that nonlinear distortion during propagation inside the trunk is relevant, and the brassy aspect of trumpet calls can be explained as a consequence of nonlinear propagation in the extended vocal tract (including the trunk). In other words, the explanation of the brassy aspect of the elephant trumpet calls seems to be the same as the explanation of the brassy sounds from trumpet or trombone musical instruments.”

Two stereo recordings (both in low-level .wav format) are provided for download :

one of an elephant, and another of a trombone imitating an elephant.

The full paper : Does the elephant trumpet like a trumpet?  was presented at the
International Congress on Acoustics ICA2010: (20th International Congress on Acoustics, Sydney, Australia, 23-27 August, 2010.)

 






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