Car interior acoustics

The aim of this project was to improve the interior acoustics of small automobiles. As such, the modeling, calculation and evaluation of the sound propagation inside the vehicle is necessary.

Due to the relevant frequency bandwidth of 20 Hz – 20.000 Hz and the availability of FEM-software, splitting the calculations is advantageous – in Finite Element and Raytracing models. The mesh density has to be chosen in such a way that the wave lengths can be solved with the corresponding amount of elements.

• Finite Element Mesh for low frequencies
• Ray Tracing Mesh for high frequencies

The central task consisted of correctly modeling the interior volume of the vehicle cabin. However, especially the area in vicinity to the doors, which almost always contains speakers, contains important questions of a mechanical nature as the door panels are used to store the speakers.

The analyses provide aide in evaluating the interior acoustics during the design phase and in avoiding the development of grave errors. This includes the amount of speakers, their parameters and the placement within the vehicle. The activation of air volume inside the boot, the doors and the side panels are crucial for the development of high-end acoustics.