Acoustic calculations using the boundary elements method

This numerical calculation method enables the simulation of the sound field under basically any conditions. For us as studio planners, it is particularly interesting that the acoustic behavior of complex rooms, i.e. rooms that are not cuboid, can also be mapped.

Simulation of the sound field under basically any conditions

The natural modes of a room dominate its bass behavior and can only be calculated for cuboid geometries. However, there are good reasons to build recording and control rooms with non-parallel walls and sloping ceilings. In these cases, the calculation of the “Eigenmoden” is only possible with the BEM method.

In order to calculate the acoustics of a studio room using the boundary elements method, a three-dimensional geometric model is created and the acoustic properties of the surfaces are stored. Loudspeaker and listening positions can also be specified and the frequency response to be expected can be calculated.

However, measurements still make sense, because any calculation is only as good as the data on which it is based. While the geometry is easy to map, estimating the acoustic impedances (degree of absorption) of the individual surfaces in the existing building is often not easy. This error can be significantly minimized by comparing it with real measurement data, so that the results of the method become reliable.

Unforeseen possibilities to predict future acoustics

The use of the BEM method for planning professional studio rooms offers hitherto unimagined possibilities in terms of forecasting future acoustics. Time-consuming trial and error phases are minimized, expensive measurements are kept to a minimum and planning security is significantly increased.

The following figures show the calculation of the sound pressure level in a control room with an adjacent vocal booth at different frequencies. Even if the deviations from the ideal cuboid are small (front, sloping ceiling), this example impressively demonstrates the possibilities of the BEM process:

45 Hz measurement I Acoustic calculations using the Boundary Elements Method (BEM)

57 Hz measurement I Acoustic calculations using the Boundary Elements Method (BEM)

64 Hz measurement I Acoustic calculations using the Boundary Elements Method (BEM)

comparison measurements I Acoustic calculations using the Boundary Elements Method (BEM)