Abstract: In at least one embodiment, an active noise cancellation (ANC) system is provided. An audio signal source provides an audio signal. At least one loudspeaker projects anti-noise sound within a cabin. At least one microphone provides a first error signal indicative of the noise, the audio signal, and the anti-noise sound and a second error signal indicative of an estimated anti-noise signal. At least one controller is programmed to receive the first error signal and the second error signal and to provide an estimated impulse response based at least on the first error signal and the second error signal. The at least one controller is further programmed to compare the estimated impulse response to one or more pre-stored impulse responses; and to select a first pre-stored impulse response that matches the estimated impulse response to filter one or more reference signals at an adaptive filter to generate the anti-noise signal.

Abstract: A system and method for estimating secondary path impulse response (IR) for an active noise cancellation (ANC) system to enhance performance of the ANC system in a near-imperceptible manner is provided. An adaptive music interference canceller (AMIC) uses music signals as test signals and ANC error microphones to estimate the secondary path IR between all speakers and microphones. The system validates that the music signals have sufficient audio content to be considered an adequate test signal. Furthermore, the system employs additional signal processing to ensure that a unique IR for all speakers and microphones can be obtained using the audio test signals. New coefficients of the AMIC filter are calculated, in real time, using the music signals and can be copied into the estimated secondary path for the ANC system. A supervisor unit manages enabling and disabling the AMIC as needed for calculating and copying coefficients.

Abstract: A system and method for accurately estimating engine noise at a virtual microphone location, such as an occupant's ear position, in an acoustic space in order to enhance performance of an Engine Order Cancellation (EOC) system is provided. A set of weights and transfer functions that are dependent on various vehicle parameters, such as frequency, load, and speed, may be employed to estimate noise at a position where there are no physical microphones present. The accurate estimation of engine noise at virtual location, such as an occupant's ear position, may be achieved using a frequency dependent weighted sum of filtered and unfiltered error signals measured at microphones mounted at various locations inside an acoustic space, such as a vehicle cabin, which may not be located near virtual location.