Identification and characterization of interior noise sources become a necessary step in air-craft or automotive industry to improve acoustic comfort. For several years, MicrodB and LMS have developed and commercialized a well-suited tool for interior noise localization based on a spherical rigid array. Indeed, taking into account the scattering of sound pressure field on the array improves drastically its directivity, reducing the influence of reflections inside the cavity. It is however difficult to obtain a good balance between low frequencies spatial resolution, dynamic, under-sampling in high frequencies, number of microphones and thus number of acquisition channels. A solution developed by MicrodB consists in adding extensions with microphones on the rigid spherical array to create an open spherical array with a larger diameter. This double spherical array associated with multi-array processing, based on beamforming techniques, combines advantages of the open sphere, mainly its good spatial resolution and dynamic in low frequencies, and the rigid sphere, its good directivity allowing localization in reverberant conditions. Some examples present interesting results obtained in in-flight measurements and inside vehicle.
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