An active noise control apparatus of vehicles capable of making it difficult for a passenger in a vehicle to hear the voice of another passenger, achieving privacy protection, and a method of controlling the same are disclosed. The active noise control method includes primarily determining a noise level based on a first microphone signal input through a microphone corresponding to a first seat, secondarily determining whether to output an anti-noise signal generated based on the first microphone signal and the magnitude of the anti-noise signal based on the noise level and the level of the first microphone signal, and outputting the anti-noise signal through a headrest speaker of a second seat in response to the secondary determining.

Detecting a divergence in an adaptive system includes the steps of determining a power of a component of an error signal at a first frequency, the component being correlated to a noise-cancellation signal, the noise-cancellation signal being produced by an adaptive filter and being configured to cancel noise within a predetermined volume when transduced into acoustic signal, wherein the error signal represents a magnitude of a residual noise within the predetermined volume; determining a time gradient of the power of the component of the error signal; and comparing a metric to a threshold, wherein the metric is based, at least in part, on a value of the time gradient of the power of the component of the error signal over a period of time.

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.

Adaptive noise cancellation systems and methods comprise a reference sensor operable to sense environmental noise and generate a corresponding reference signal, an error sensor operable to sense noise in a noise cancellation zone and generate a corresponding error signal, a noise cancellation filter operable to receive the reference signal and generate an anti-noise signal to cancel the environmental noise in the cancellation zone, an adaptation module operable to receive the reference signal and the error signal and adaptively adjust the anti-noise signal.

A helmet including an active noise cancellation (ANC) system which includes a first reference microphone for measuring sound pressure at a first location on a first side of the helmet, the first location between a defined spatial region and a first source of sound and a second reference microphone for measuring sound pressure at a second location, different to the first location, on the first side. The second location is between the defined spatial region and a second source of sound. A loud speaker is provided in or adjacent to the defined spatial region. A control unit determines, based on output signals from the first and second microphones, a drive signal for driving the loudspeaker to generate a sound signal that at least partially attenuates, in the defined spatial region and in the first frequency range, the sound signals from the first and second noise sources.

A transfer function of a first variable filter is updated to output, from an output of a first seat microphone, a cancel sound that minimizes a level of a signal obtained by subtracting an output of an auxiliary filter that generates a correction signal for correcting a difference between positions of the first seat microphone and the first seat. In the ICC mode in which the uttered voice of the user in the first seat is output from a second seat speaker, a selector sets an uttered voice Dp output from the second seat speaker as an input to the first variable filter, and in the non-ICC mode, the selector sets an output sound of a second seat audio source output from the second seat speaker as an input to the first variable filter. The uttered voice Dp is generated by removing a component of the cancel sound from the output of the first seat microphone.

A first variable filter receives a sound of a second seat audio source as an input and generates a cancel sound for canceling the sound of the second seat audio source at a first seat. The transfer functions of the first variable filter and the second variable filter are updated such that the level of a signal obtained by subtracting the output of the auxiliary filter that generates a correction signal for correcting the difference between the positions of the first seat microphone and the first seat and the output of the second variable filter that receives the sound of the first seat audio source from the output of the first seat microphone is minimized. While the level of the signal exceeds a threshold, the signal is relayed to the second seat as a spoken voice.

Embodiments and methods perform ear cavity frequency response (EFCR) adaptive noise cancelation (ANC) with path-compensation over an entire main path to the eardrum (MPED) of a user. A number of ANC filter models are pre-trained to include respective anti-noise path (ANP) filter models and respective MPED filter models representing ANC filter configurations. As a user wears a headphone earpiece, characteristics of the wearer and the position/orientation of wearing manifest a wearer/wearing condition. Techniques described herein can continuously or periodically and efficiently determine which of the pre-trained ANC filter models most closely described the present MPED of the present wearer/wearing condition, and can continuously or periodically update the ANC filter configuration based on the pre-trained models to maintain high-performance ANC that includes EFCR path-compensation.

An active noise reduction device includes: a reference signal input terminal that receives a reference signal from a reference signal source attached to an automobile; a simulated vibration transfer characteristics filter unit that generates a second signal by correcting, using simulated vibration transfer characteristics, a first signal for outputting, from a loudspeaker attached to the automobile, a sound different from a canceling sound, the simulated vibration transfer characteristics simulating vibration transfer characteristics from the loudspeaker to the reference signal source; a first subtracter that outputs a corrected reference signal obtained by subtracting the second signal generated, from the reference signal received by the reference signal input terminal; and an adaptive filter unit that applies an adaptive filter to the corrected reference signal outputted from the first subtracter to generate a canceling signal to be used to output the canceling sound.

Various aspects include active noise reduction (ANR) devices and approaches, one approach including: receiving an input signal representing audio captured by a feedforward microphone of an ANR headphone; receiving an error signal representing audio captured by an error measurement sensor; generating an anti-noise signal configured to reduce a noise signal over a frequency range; and applying a gain to at least one of the input signal or the anti-noise signal over the frequency range based on the error signal, wherein the applied gain is configured to enhance noise reduction for a plurality of users having distinct fits for the ANR headphone.