Active noise cancellation systems and methods include a feedforward path configured to receive a reference signal comprising ambient noise and adaptively generate an anti-noise signal to cancel the ambient noise. The adaptive filter is tuned in accordance with at least one parameter, which is set by a logic device configured to determine an ambient noise condition based the reference signal by estimating a fullband power of the reference signal, estimating a low-frequency power of the reference signal, comparing the fullband power and low-frequency power to one or more thresholds, and/or setting one or more ambient noise flags. The ambient noise condition may include a quiet background, a wideband noise condition, and/or a low-frequency dominant noise condition.

A method performed by a wearable audio output device worn by a user is provided for controlling external noise attenuated by wearable audio output device. A speech is detected from a user wearing the wearable audio output device, wherein the audio output device has active noise reduction turned on. It is determined, based on the detecting, that the user desires to speak to a subject in the vicinity of the user. In response to the determining, a level of noise reduction is reduced to enable the user to hear sounds external to the audio output device. It is determined that the user desires to speak to the subject by detecting at least one condition of a plurality of conditions.

An active vibratory noise reduction system includes: a first estimation signal generation section configured to generate a vibratory noise estimation signal by processing standard cosine and sine wave signals with correction filters corresponding to signal transfer characteristics from a vibratory noise source to an error signal detector; a second estimation signal generation section configured to generate a canceling vibratory noise estimation signal from the standard cosine and sine wave signals by using first and second adaptive notch control filters; a virtual error signal generation section configured to generate a virtual error signal from the vibratory noise estimation signal and the canceling vibratory noise estimation signal; and a filter coefficient updating section configured to sequentially update filter coefficients of the first and second adaptive notch control filters based on first and second reference signals and the virtual error signal such that the first virtual error signal is minimized.

The present disclosure provides an acoustic device including a microphone array, a processor, and at least one speaker. The microphone array may be configured to acquire an environmental noise. The processor may be configured to estimate a sound field at a target spatial position using the microphone array. The target spatial position may be closer to an ear canal of a user than each microphone in the microphone array. The processor may be configured to generate a noise reduction signal based on the environmental noise and the sound field estimation of the target spatial position. The at least one speaker may be configured to output a target signal based on the noise reduction signal. The target signal may be used to reduce the environmental noise. The microphone array may be arranged in a target area to minimize an interference signal from the at least one speaker to the microphone array.

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.

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.

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.

The present disclosure provides an acoustic device including a microphone array, a processor, and at least one speaker. The microphone array may be configured to acquire an environmental noise. The processor may be configured to estimate a sound field at a target spatial position using the microphone array. The target spatial position may be closer to an ear canal of a user than each microphone in the microphone array. The processor may be configured to generate a noise reduction signal based on the environmental noise and the sound field estimation of the target spatial position. The at least one speaker may be configured to output a target signal based on the noise reduction signal. The target signal may be used to reduce the environmental noise. The microphone array may be arranged in a target area to minimize an interference signal from the at least one speaker to the microphone array.

One aspect of the present disclosure relates to a noise masking method through variable masking sound level conversion, capable of adjusting an interval for changing a level of a masking sound for masking noise to an optimal interval so that the masking sound is not perceived as noise, by determining a fluctuation trend of a level of audible noise and adjusting the interval for changing the level of the masking sound for masking the noise into an optimal environment through a control unit.