A method may include adaptively generating an anti-noise signal for countering the effects of ambient audio sounds at an acoustic output of the transducer by adapting a response of an adaptive filter that filters a reference microphone signal in conformity with an error microphone signal and the reference microphone signal to minimize the ambient audio sounds in the error microphone, generating a scaled anti-noise signal by applying a scaling factor to the anti-noise signal, further adjusting the response of the adaptive filter independent of a source audio signal by altering an input to the coefficient control block of the adaptive filter to compensate for the scaling factor, and combining the scaled anti-noise signal with the source audio signal to generate an audio signal provided to the transducer.

An electric powered work machine according to one aspect of the present disclosure includes a first and a second digital filters, a control sound source, an error sensor, and a characteristics adjustor. The first digital filter includes a series of taps and generates a control signal. The control sound source produces an artificial noise in accordance with the control signal. The error sensor converts a synthesized sound of the artificial noise and a target noise at a canceling location to an error signal. The second digital filter includes N taps and generates a filtered reference signal. The characteristics adjustor uses the error signal and the filtered reference signal to adjust a coefficient of each tap of M taps in the series of taps. Each of M and N is a positive integer satisfying M<N.

An active noise control device includes a secondary path filter coefficient updating unit. The secondary path filter coefficient updating unit is configured to update a coefficient of a secondary path filter by using a coefficient of the secondary path filter after previous updating as a previous value, when a phase characteristic of the secondary path filter that sets an initial value as the coefficient and a phase characteristic of the secondary path filter that uses the previous value as the coefficient are not approximate to each other.

An active noise control device performs signal processing on a basic signal corresponding to a control target frequency by a control filter, which is an adaptive notch filter, to generate a control signal that controls a speaker, sequentially and adaptively updates coefficients of the control filter, compares a magnitude of a primary path filter with a magnitude of the control filter, and determines whether the state of the control filter is unstable or not.

An active noise control device includes a control signal generating unit including a first adaptive filter configured to generate a control signal by performing a filtering process on a reference signal corresponding to noise, an identifying unit configured to identify a peak frequency in an impedance frequency characteristic of an actuator, a peak frequency storage unit configured to store an initial peak frequency of the actuator, a first determination unit configured to determine whether or not a difference between the peak frequency currently identified and the initial peak frequency is greater than or equal to a threshold value, and a control unit configured to change a characteristic of the control signal generated by the control signal generating unit when the first determination unit determines that the difference is greater than or equal to the threshold value.

An active noise control device includes a first adaptive filter configured to generate a control signal by performing a filtering process on a reference signal corresponding to noise, and a first filter coefficient updating unit configured to update a filter coefficient of the first adaptive filter based on based on the reference signal and an added error signal acquired by adding a first error signal acquired by detecting residual noise by a first microphone and a second error signal acquired by detecting residual noise by a second microphone.

Methods, systems, computer-readable media, and apparatuses for audio signal processing are presented. A device for audio signal processing includes a memory configured to store instructions and a processor configured to execute the instructions. When executed, the instructions cause the processor to receive an external microphone signal from a first microphone and produce a hear-through component that is based on the external microphone signal and hearing compensation data. The hearing compensation data is based on an audiogram of a particular user. The instructions, when executed, further cause the processor to cause a loudspeaker to produce an audio output signal based on the hear-through component.

An active noise cancellation (ANC) system may include an adaptive filter divergence detector for detecting divergence of the one or more controllable filters as they adapt, based on dynamically adapted thresholds. Upon detection of a controllable filter divergence, the ANC system may be deactivated, or certain speakers may be muted. Alternatively, the ANC system may modify the diverged controllable filters to restore proper operation of the noise cancelling system.

Methods, systems, computer-readable media, devices, and apparatuses for synchronized mode transitions are presented. A first device configured to be worn at an ear includes a processor configured to, in a first contextual mode, produce an audio signal based on audio data. The processor is also configured to, in the first contextual mode, exchange a time indication of a first time with a second device. The processor is further configured to, at the first time, transition from the first contextual mode to a second contextual mode based on the time indication.

Provided is an information processor including a signal processing section that acquires a first signal to be detected by an acoustic input section of a first unit including the acoustic input section disposed within a predetermined distance from one ear hole of a user in a state of being worn by the user, acquires a second signal, which indicates a noise generated from a noise source, to be acquired by a second unit, and generates a noise cancellation signal directed to the noise on the basis of the first signal and the second signal.