The real car model was calculated with three different side mirror geometries because of the long range goal to relate mirror geometries to sound generation and sound propagation mechanisms in the region of the side window. The first geometry was the old series rear mirror of the S-Class, the second was the new series rear mirror and the third simulated model was the S-Class without any rear mirror. It could be shown that the simulation results of all the three geometries agreed well with measured data for frequencies up to 1 kHz and more. The comparison of the two rear mirror geometries showed that the new series rear mirror influenced the direction of the mirror wake leading to an increase of the distance between mirror wake and side window. The unsteady flow results serve as basis for subsequent sound propagation calculations. As first attempt to calculate sound Lighthill's Acoustic Analogy was solved using the FEM method of ACTRAN/LA. A hybrid method was used as first attempt to numerically determine sound propagation in the vicinity of the side window. In this way a DES-Simulation was performed in the first step to capture the unsteady and turbulent sound sources in the fluid as basis for the sound propagation computation with Lighthill's Acoustic Analogy afterwards. Lighthill's Acoustic Analogy was derived by Sir James Lighthill in the 1950s. He rearranged the Navier-Stokes equations into an inhomogeneous wave equation, thereby making a connection between fluid mechanics and acoustics. ACTRAN/LA is a Finite Element acoustic solver which was used for discretization of Lighthill's inhomogeneous wave equation. The right hand side of the inhomogeneous Lighthill equation is given by the unsteady flow results. Due to different discretization methods for the flow and acoustics solver it is favourable to use two different meshes for calculation. This needs an interpolation of the unsteady flow results of the CFD mesh onto the acoustics mesh. The interpolation of the velocity field onto the acoustics mesh and the calculation of Lighthill's Tensor are done in ACTRAN/LA. The last step solves the wave equation and gives the pressure level in frequency domain. An example of the pressure distribution is shown in the vicinity of the rear mirror. The chosen frequency is f = 168Hz and the results are shown for the plane z=0,68m.