Localization of tire/pavement noise source regions

Radiation of noise generated by the interaction of automobile tires with pavement surfaces is localized to the area immediately around the contact patch. To separate sources of tire/pavement interaction noise, measurements were conducted with three reference microphones and a planar array of microphones. Partial coherence processing between signals from the reference microphones and signals from the array microphones was employed to separate three sources of the tire/pavement interaction noise, e.g. trailing edge and leading edge of the contact patch, and the sidewall. The partially coherent signals from the array were used in Nearfield Acoustical Holography to refine the quantification of contributions to the tire/pavement interaction noise emitted from these three source regions. Measurement results are presented for blank, monopitch and commercially-available ribbed automobile tires on a smooth and rough pavement surface.