The Vibroacoustic Interaction In Mallet Percussion Instruments: Modelling And Experiments

In some mallet percussion instruments, such as vibraphones and marimbas, tubular acoustic resonators areplaced beneath the tuned bars to enhance sound radiation. Although widely used in commercial instruments, thevibroacoustic interaction between the tuned bars and theirresonators has not been studied extensively, and previousmodelling attempts regularly neglect important aspects ofthe coupling dynamics. This work develops on a previousstudy, where a minimal model for the coupling between asingle bar mode and a single resonator mode was presented. Here, the same modelling principles are applied toa system composed of a 1-D beam and a 1-D cylindricalacoustic resonator, leading to a lumped-parameter modelincluding the coupling dynamics between several barmodes and several resonator acoustic modes. The dynamics of the lumped-parameter model are explored throughtime-domain simulations and eigenvalue analysis, revelinga number of interesting (and rarely mentioned) features, forexample: the role of the ratio of damping coefficients between a bar mode and a resonator mode, the placementof the resonator along the bar’s length as well as its proximity to the bar, etc. Additionally, experimental results arepresented to validate the model and demonstrate its capacity to emulate real instruments, both qualitative andquantitatively.