The boundary conditions of the inner vehicle compartment, such as sound absorption of the lining materials and panel vibrations have a considerable influence in the acoustic comfort of the passengers and driver. The numerical simulation of the irregular cabin with the finite element method (FEM) and/or the boundary element method (BEM) have a great advantages in the modeling of the acoustic energy injected and/or absorbed by the inner cabin surfaces. In this paper, a numerical modeling of a vehicle cabin is presented by FEM and BEM. The panel vibration, between the engine compartment and passenger compartment was considered as the noise source. Prediction of the sound pressure level generated at the driver ear position was calculated for different absorption materials at the roof. This model allows optimization of the lining material and investigates the effect of panel vibration, leakage due to gaps and holes and also cabin geometry.