Frequency-Dependent Absorbing Boundary Implementations in 3D Finite Difference Time Domain Room Acoustics Simulations

Finite Difference Time Domain room acoustics modelling provides accurate emulation of sound propagation within enclosed structures. Inclusion of frequency-dependent boundary conditions in such models facilitates emulation of realistic sound wave interaction with absorbing surface materials. These boundary conditions can be implemented by means of octave band modelling or digital impedance filter methods. This paper extends research in this area by comparing results obtained from these boundary modelling methods in terms of accuracy and required computational resources. Results show that octave band approaches achieve a higher degree of accuracy over the digital impedance filter method. However, in terms of simulation run times, the octave band model must make use of parallel computation architectures to realise a simulation time lower than the digital impedance filter model. Furthermore, the results presented inform routes of further study focussing on refinement of both methods to create an optimal, computationally efficient frequency-dependent boundary model.