Calcada, M., Rocha, T., and Ribeiro, Y., "Integrated use of Noise Source Identification Techniques during Vehicle Development," SAE Technical Paper 2012-36-0642, 2012, doi:10.4271/2012-36-0642.
Currently, acoustic holography and beamforming are consolidated Noise Source Identification (NSI) techniques with expanding applications. These two microphone array based techniques can provide detailed sound field visualization. Even in enclosed space, such as a vehicle cabin, the sound field can be visualized using Spherical Harmonics Beamforming (SHB). Also, sound radiation from geometrically complex surfaces can be captured with conformal mapping using Statistically Optimized Near-field Acoustic Holography (SONAH). In this paper, an integrated approach using both techniques is presented as a manner to improve sound insulation during a vehicle development. Both vehicle and component level measurements are employed in order to identify the dominant sound transmission paths and add the appropriate acoustic treatments. It is shown that spherical beamforming and conformal mapping are powerful tools which expedite troubleshooting and allow vehicle acoustic content optimization.