Experimental Analysis of Spatial Properties of the Sound Field Inside a Car Employing a Spherical Microphone Array

A 32-capsules spherical microphone array was employed for analyzing the spatial properties of the sound field inside a car. Both the background noise and the sound generated by the car's sound system were spatially analyzed, by superposing false-color sound pressure level maps over a panoramic 360x180 degrees image, obtained with a parabolic-mirror camera. The analysis of the noise field revealed the parts of the car body where more noise is leaking in, providing guidance for better soundproofing. The analysis of the impulse responses generated by the loudspeakers did show useful information on the reflection patterns, providing guidance for adding absorbent material in selected locations and for optimizing position and orientation of loudspeakers.