Efficient low frequency room acoustic modelling

Boris Jean-Francois Mondet


Room acoustic simulations are used worldwide to predict the behaviours of newly designed and renovated rooms. On one hand, current software proposing room acoustic simulations are based on geometrical acoustics, a high-frequency approximation offering relatively short computation times. However, assumptions behind geometrical acoustics do not hold at low frequencies or for small rooms. On the other hand, wave-based simulation methods can return accurate results for low frequencies, but at the cost of long computation times. Because of this, simulation of ordinary rooms like offices or classrooms is a major challenge in room acoustics.


The aim of the project is to develop a new calculation method for room acoustic simulations at low frequencies. The method will consist in a two-step solution to determine the sound field in a room: a first approximation will be calculated with geometrical acoustics, then the effects previously neglected will be accounted for with a wave-based method. By doing so, the wave-based method will only be applied to a fraction of the sound field, and the increase in computation time will be limited. Going from geometrical acoustics to wave-based methods also requires an adaptation of the input data to the simulation. Phased parameters are needed for the boundary representation, as opposed to the current energy parameters. Because of this, an input data conversion will take place prior to the simulation itself.


The new calculation method will eventually be implemented in the Odeon software, allowing more accurate simulations and more efficient work for acoustic consultants. It will also extend the possibilities of room acoustics to the field of transportation by enabling the prediction of sound field in cars, trains and aircrafts.


Jonas Brunskog (DTU Acoustic Technology)

Cheol-Ho Jeong (DTU Acoustic Technology)

Claus Lynge Christensen (Odeon A/S)

21 OCTOBER 2020