22 research outputs found
Percussion instrument modelling In 3D: sound synthesis through time domain numerical simulation
This work is concerned with the numerical simulation of percussion instruments based on physical
principles. Three novel modular environments for sound synthesis are presented: a system
composed of various plates vibrating under nonlinear conditions, a model for a nonlinear double
membrane drum and a snare drum. All are embedded in a 3D acoustic environment. The approach
adopted is based on the finite difference method, and extends recent results in the field.
Starting from simple models, the modular instruments can be created by combining different
components in order to obtain virtual environments with increasing complexity. The resulting
numerical codes can be used by composers and musicians to create music by specifying the
parameters and a score for the systems. Stability is a major concern in numerical simulation.
In this work, energy techniques are employed in order to guarantee the stability of the numerical
schemes for the virtual instruments, by imposing suitable coupling conditions between the
various components of the system.
Before presenting the virtual instruments, the various components are individually analysed.
Plates are the main elements of the multiple plate system, and they represent the first approximation
to the simulation of gongs and cymbals. Similarly to plates, membranes are important
in the simulation of drums. Linear and nonlinear plate/membrane vibration is thus the starting
point of this work. An important aspect of percussion instruments is the modelling of collisions.
A novel approach based on penalty methods is adopted here to describe lumped collisions with
a mallet and distributed collisions with a string in the case of a membrane. Another point
discussed in the present work is the coupling between 2D structures like plates and membranes
with the 3D acoustic field, in order to obtain an integrated system. It is demonstrated how
the air coupling can be implemented when nonlinearities and collisions are present. Finally,
some attention is devoted to the experimental validation of the numerical simulation in the
case of tom tom drums. Preliminary results comparing different types of nonlinear models for
membrane vibration are presented
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An Energy Conserving Finite Difference Scheme for the Simulation of Collisions in Snare Drums
In this paper, a physics-based model for a snare drum will be dis-cussed, along with its finite difference simulation. The interac-tions 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. 1