aSorbonne Université, CNRS, Institut Jean Le Rond d'Alembert
bMuséum National d'Histoire Naturelle, CNRS, éco-anthropologie et ethnobiologie
Abstract :
Traditional instruments handed down from generation to
generation, Gabonese harps have various shapes, often
anthropomorphic, that depending on the population and the
region concerned. Nevertheless, harps are all composed of
eight strings, each wrapped up on one side to a tuning peg
fixed on the neck and at the other side linked to a wooden
tailpiece. It is often nailed to both ends of the resonance box,
under the soundboard made of animal skin. In order to study
the evolution of these instruments within the framework of a
multidisciplinary project, an acoustic modelling of the instrument
is undertaken. The main objective of this modelling is to
understand and highlight maker’s elements that predominate in
their sound. For this purpose, the Udwadia- Kalaba formulation is
used to model vibrating systems coupled together by
mechanical constraints. In particular, this formulation can take
into account geometrical non-linearities of strings induced by
their high-amplitude
excitation. Model parameters were first extracted from an
instrument at our disposal. Then, time-domain simulations
were confronted to experimental data. Finally, a parametrical
study showed that the low string tension and modal
behaviour of the tailpiece are of great importance in the
characteristic sound of the instrument.