A device and method that is configured to operate an active noise reduction system for a motor vehicle, where there is an active noise reduction system input signal that is related to the vehicle engine speed, and where the active noise reduction system comprises one or more adaptive filters that use a filter coefficient to modify the amplitude and/or phase of a noise cancellation reference signal and output noise reduction signals that are used to drive one or more transducers with their outputs directed to reduce engine noise, where the value of the coefficient is related to an adaptive filter leakage factor. Changes in the engine speed, based on the input signal that is related to the vehicle engine operation, are monitored. In response to changes in the engine speed, the adaptive filter leakage factor is temporarily modified.