Abstract: Noise cancellation systems and methods are provided that generate an anti-noise signal configured to destructively interfere with noise in a cancellation zone. The systems and methods receive a signal representative of the noise in the cancellation zone. The signal is analyzed to identify a frequency to be reduced in the cancellation zone, and the signal is down converted to place the identified frequency at baseband. A baseband anti-noise signal is generated based upon the down converted signal. The baseband anti-noise signal is up converted to the identified frequency to produce an anti-noise signal having components at the identified frequency, and the anti-noise signal is provided to be transduced into an acoustic signal.

Abstract: Audio systems, methods, and computer readable mediums having program code to receive a harmonic signal related to rotating equipment, such as a vehicle drivetrain in some examples, and provide a harmonic cancellation (or enhancement) signal. The harmonic cancellation signal is transduced into an acoustic signal, and a feedback sensor, such as a microphone, detects an error signal representative of acoustic energy at a first location in the environment. A projection filter filters the error signal to provide an estimated error signal at a second location in the environment, such as at the location of an occupant's ear(s). An adaptive module adjusts the cancellation signal based on the estimated error signal.

Abstract: Noise cancellation systems and methods are provided that receive a reference signal representative of a noise to be reduced and provide a noise cancellation signal based upon the reference signal. Some examples include a feedback signal representative of a residual noise in the environment. At least one of the reference signal, the noise cancellation signal, or the feedback signal is filtered to remove components based upon a rotational rate of a rotating equipment associated with the environment, such as an engine of a vehicle. Accordingly, the noise cancellation system may not interfere with sounds related to the engine.

Abstract: Noise cancellation systems and methods are provided that generate an anti-noise signal configured to destructively interfere with noise in a cancellation zone. The systems and methods receive a signal representative of the noise in the cancellation zone. The signal is analyzed to identify a frequency to be reduced in the cancellation zone, and the signal is down converted to place the identified frequency at baseband. A baseband anti-noise signal is generated based upon the down converted signal. The baseband anti-noise signal is up converted to the identified frequency to produce an anti-noise signal having components at the identified frequency, and the anti-noise signal is provided to be transduced into an acoustic signal.