Collisions play a major role in various models of musical instruments; one particularly interesting case is that of the guitar fretboard, the subject of this paper. Here, the string is modelled including effects of tension modulation, and the distributed collision both with the fretboard and individual frets, and including both effects of free string vibration, and under finger-stopped conditions, requiring an additional collision model. In order to handle multiple distributed nonlinearities simultaneously, a finite difference time domain method is developed, with a penalty potential allowing for a convenient model of collision within a Hamiltonian framework, allowing for the construction of stable energy-conserving methods. Implementation details are discussed, and simulation results are presented illustrating a variety of features of such a model.

Download

In this paper, a physics-based model for a snare drum will be discussed, along with its finite difference simulation. The interactions between a mallet and the membrane and between the snares and the membrane will be described as perfectly elastic collisions. A novel numerical scheme for the implementation of collisions will be presented, which allows a complete energy analysis for the whole system. Viscothermal losses will be added to the equation for the 3D wave propagation. Results from simulations and sound examples will be presented.

Download