Modelling and measurement of complex boundary properties
This project focuses on the numerical modelling of enclosed spaces (rooms, car/train/plane interiors etc.) to acquire their correct impulse responses before the environment is actually built. Other than today’s frequently used methods, which are mostly based on ray-tracing, mirror image source or a combination of the previous two (hybrid), this project uses a wave field extrapolation method. The idea for this method has its origin in the field of seismic exploration, where it is utilized to image ground layers. By using a wave based method it is possible to correctly describe wave propagation in enclosed spaces, but, more important, also to predict diffraction caused by the structures and shape of the boundaries. Moreover, it is also possible to assign complex reflection properties to the wall configurations. The goal of this project is to develop a simulation tool for enclosed spaces, which is based on the prediction of physical phenomena and therefore able to deal with diffraction and complex reflection properties of the environment boundaries. This can be a helpful tool in the design of new concert halls, recording studios, theatres, vehicle interiors etc. Furthermore, a method will be developed to determine the reflection properties of common room boundary configurations from array impulse response measurements to compose a library of input data for the simulation tool. The general focus of this simulation and measurement methods is to be able to investigate the properties of non-locally reacting boundaries.