Leakage identification for a vehicle firewall sound transmission by beamforming technique.
Yuri Ribeiro, William D’Andrea Fonseca, Gerges Samir · The Journal of the Acoustical Society of America · 2009
The acoustic phased array is a powerful tool for identification and quantification of noise sources on complex systems. Acoustic sources generate waves which propagate through space to the N microphones of the array. The acoustic pressures are sampled and converted to time series data and processed using either time domain or frequency domain delayed and averaged. The output of signal processing is a colored image with relative sound pressure levels distribution. In this paper application of beamforming technique is used to identify leakage areas in a vehicle firewall. Two acoustic rooms are used and the firewall was installed in the apertures inbetween with careful control of noise flank paths. Source room was excited with white noise and a phased array microphone was used to measure the sound field in the anechoic receiving room. The firewall was evaluated both with all holes sealed and with the regular pass-through components installed. Two different acoustic insulators were also tested on the firewall. The results show clearly the areas of leakage with relative noise levels at each test configuration.