Evaluation of the Ray-Tracing and Pressure Acoustic Solvers for Audio Simulations in a Vehicle
For automotive applications, acoustical simulation methods are used to optimize the position and orientation of the loudspeakers to get the best audio system performance. The goal of the presented paper is to evaluate the accuracy of the Pressure Acoustics interface (Finite Element, wave-based method) and the Ray Acoustics interface (geometrical acoustics) to predict the acoustic responses in the vehicle interior. For this study, 2 midranges located in the front doors were simulated from 50 Hz to 4 kHz. To validate the simulation results, an experimental comparison between simulated and measured responses was performed. A planar microphone array, located at the four seat positions, was employed to capture the responses in the experimental and virtual setup. Based on material sample measurement, frequency dependent absorption coefficients were assigned as boundary wall conditions. For the FEM simulations, the LiveLink™ for MATLAB® interfacing product is used to preprocess, solve, and export the simulation data. For the Ray Acoustics interface, the speaker is modeled by means of a measured sensitivity and directivity performed in an anechoic room. From the FEM simulation, the corresponding acoustic impulse responses were computed and merged with the ray tracing impulse responses. The comparison in the frequency domain shows that the combination of the Pressure Acoustics and Ray Acoustics interfaces can perform accurate speaker simulations in a vehicle. To include the influence of the speaker packaging in the car cabin (lens, wave guide, grille), or to simulate a non-existing speaker, the coupling between the FEM and ray tracing is discussed.
