Vehicle interior audio system noise prediction based on inverse acoustic approach and directivity pattern

Automotive audio components must meet high quality expectations with ever-decreasing development costs. Predictive methods for the performance of sound systems in view of the optimal locations of loudspeakers in a car can help to overcome this challenge. Use of simulation methods would enable this process to be brought up front and get integrated in the vehicle design process. The main objective of this work is to develop a virtual auralization model of a vehicle interior with audio system. A hybrid simulation approach, which combines both the ray based & finite element approach to predict acoustic transfer functions & auralization effects across the audible frequency range on any chosen vehicle variant. In this paper, Acoustic Vehicle Alerting System (AVAS) speaker tested in an acoustic lab is used. The surface vibration pattern over the surface of the virtual speaker is first extracted based on measured sound pressure data. The acoustic response in a free field generated by the virtual speaker is validated by comparing the SPL from direct measurements and from numerical prediction. The validated virtual speaker with vibration pattern is then applied in a full vehicle model to predict interior sound field. Investigated the interior noise due to AVAS speaker with its directivity considered. Inverse numerical acoustics used to retrieve the surface normal velocities on the acoustic model. The INA technique allows to back calculate the operational vibrations based on operational near field pressure measurements. Near field pressure measurements are required to capture all acoustic waves (radiated waves + evanescent waves). In this work, radiated pressures measured at the near field of AVAS speaker. Predicted velocities are used to calculate the radiated pressures and power at far field microphones. In order to listen the sound in the vehicle interior, performed sound processing and auralization by convolving the impulse response functions between the sources and microphones with an audio file (wav file). Key words: AVAS speaker, Inverse acoustics, Interior noise, Auralization