LAUM, Le Mans
Abstract :
At the last ISMA, a method for measuring the nonlinear
characteristic and the static mechanical behaviour of the
clarinet exciter (reed + mouthpiece + lip of the player) was
presented. Here, we show how this measured behaviour can be
integrated in a real time simulation using a waveguide clarinet
model, including nonlinear losses at the toneholes.
The clear separation of the aeraulic (nonlinear characteristic)
and mechanical (static bending of the reed against the
mouthpiece lay, like a stiffening spring) aspects allows a
straightforward, piecewise simulation of the dynamic behaviour,
apparently without any numerical stability problem.
For the simulation of the instrument, at a low sound level, the
proposed empirical tonehole model tends towards the linear
radiation impedance, whereas at high level, nonlinear losses
dominate. They are modelled by Bernoulli's law with turbulent
flow (as for the exciter).
Taking nonlinear losses into account is crucial for a credible
simulation of the instrument, especially in the second regime.
The model allows to realistically predict the playing frequency
and the timbre of the instrument according to the two main
objective factors characterizing clarinet reeds: stiffness and
opening at rest (without lip pressure). This allows a virtual
prototyping of the clarinet exciter and resonator.