ABSTRACT
This chapter provides an overview of computer-based acoustic modelling. As a starting point, the motivation and the goals of acoustic simulation are outlined. The importance of properly planning and commissioning modern sound reinforcement systems and acoustic spaces is explained. Subsequently, the input data required for simulations are discussed. While the geometrical information of the modelled space and its level of detail is one important aspect, the focus is on the accurate data representation for conventional loudspeakers, standard line arrays as well as digitally steered columns. Wall materials and their absorption and scattering characteristics are discussed in the same context of input data and the respective uncertainties and deficiencies. Next, the most important simulation methods are introduced, in particular ray-based and wave-based approaches. The advantages and disadvantages of commonly applied methods, such as image sources, Monte Carlo ray-tracing and cone-tracing as well as FEM, BEM and FDTD, are discussed with respect to computational replication of key acoustic aspects such as direct field, reverberation and room modes. Restrictions and calculation performance are also taken into account. In this context, an important side aspect is addressed, being that accurate simulation results enable the very powerful numerical optimization of a sound system based on FIR filters. With respect to the modelling results, typical types of output data are described and factors contributing to their overall uncertainty are highlighted and explained. These include uncertainties associated with the input data, as well as shortcomings of the chosen simulation approach and the interpretation of the results. Finally, auralization as a process of making simulated spaces acoustically audible is explained and its practical application is commented on.
