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In-vehicle reverberation time as a function of frequency can be used as one indicator of the quality of a vehicle interior as an acoustic space. Typically, however, reverberation times in passenger vehicles are so short that they can be extremely difficult to measure using interrupted noise or impulse excitations. This paper investigates a steady state method of determining reverberation times by adapting the power injection method, which is typically used to determine composite damping loss factors of panels. The results of using this method will be compared with those of other methods. Theoretical and practical advantages and disadvantages will be discussed. Application of this method to absorption measurement will be discussed as well.

Vehicle interior wind noise is typically managed through the overall exterior geometry of the vehicle, mirror shape and mounting location, sealing features and glass thickness and damping. Prior research has distinguished between contribution of fluctuating pressure due to air turbulence as compared to acoustic pressure to a passenger vehicles exterior at highway speeds. Because of the large difference in propagation speed between turbulent and acoustic pressure for on-road passenger vehicles, the structural response of the glass to turbulent versus acoustic pressure is not the same. The acoustic coincidence frequency of door glass is typically in the 2-3 kHz range. Turbulent coincidence frequency is much lower, and the effective transmission loss (TL) of the glass depends on the mix of turbulent and acoustic pressure on the exterior surface of the glass.