A biquad hybrid active noise cancellation (ANC) device includes a reference microphone (MIC), an error MiC, a speaker, and a controller. The controller is connected to the reference MiC, the error MiC, and the speaker, wherein the controller includes a feedforward biquad ANC filter, a feedback biquad ANC filter, and a mixer, the feedforward biquad ANC filter processes reference noise to generate a feedforward noise control signal, the feedback biquad ANC filter processes residual noise received by the error MiC to generate a feedback noise control signal, and the feedforward noise control signal generated by the feedforward biquad ANC filter and the feedback noise control signal generated by the feedback biquad ANC filter are added by the mixer and transmits to the speaker for playing.

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.

An active noise control device includes a basic signal generating unit configured to generate a basic signal corresponding to a resonance frequency of a vibration sensor, a first adaptive filter configured to generate a sensor resonance simulation signal simulating a signal acquired while the vibration sensor is resonating by performing a filtering process on the basic signal, a computation unit configured to calculate a second reference signal that is a difference between a first reference signal acquired by the vibration sensor and the sensor resonance simulation signal, and a second adaptive filter configured to generate a control signal by performing a filtering process on the second reference signal.

A speaker system includes a speaker, a processor, and an active noise cancellation (ANC) circuit communicatively coupled with the processor. The ANC is configured to apply ANC on audio signals from outside the speaker system to generate a modified audio signal stream through the speaker. The application of ANC is to include generation of ANC signals to interfere with at least part of the audio signals from outside the speaker system in the modified audio signal stream. The processor is configured to determine of low-frequency energy at the speaker system, the low-frequency energy below a threshold frequency. The ANC circuit is configured to, based on the determination of low-frequency energy at the speaker system, perform a corrective action on application of ANC to the audio signals from outside the speaker system.

A method for audio signal noise cancellation is provided. In response to current noise cancellation coefficients being required to be updated to new noise cancellation coefficients, the digital signal processor calculates the new noise cancellation coefficients and writes the new noise cancellation coefficients into an idle storage module in the at least two storage modules, and the digital signal processor sends an update request for updating the noise cancellation coefficients to the active noise cancellation module. The update request carries position information configured to indicate a position of the storage module to which the new noise cancellation coefficients is written. The active noise cancellation module reads the new noise cancellation coefficients in the storage module indicated by the position information based on the position information carried in the update request, and performs noise cancellation processing according to the new noise cancellation coefficients after a current noise cancellation processing cycle ends.

A noise cancellation system for an ear-mountable playback device having a speaker, a feedforward microphone and an error microphone comprises a filter chain for coupling the feedforward microphone to the speaker, the filter chain comprising a series connection or parallel connection of a coarse filter and a fine filter, and a noise control processor. The fine filter is formed of a set of sub-filters having a predefined frequency range, wherein the predefined frequency range of each of the sub-filters together forms an effective overall frequency range of the fine filter. The noise control processor is configured to calculate an error signal based on a first noise signal sensed by the feedforward microphone and on a second noise signal sensed by the error microphone, to perform an adaptation of coarse filter parameters of the coarse filter based on the error signal, and to perform a limited adaptation of fine filter parameters of each of the sub-filters based on the error signal, wherein limits of the limited adaptation comprise the predefined frequency ranges of the sub-filters and at least one of a gain limit and a Q factor limit.

The present disclosure provides systems and method for adjusting the audio output of a wearable device based on an audio gain profile of a user. The wearable device may receive an audiogram indicating one or more frequency ranges associated with hearing loss. The wearable device may determine the audio gain profile based on the audiogram. The wearable device may use one or more adjustment modules to determine a gain to apply to the audio output based on the audio gain profile. The adjustment modules may include an active noise control module, a hearing assistance module, and a transparency control module. The wearable device may determine the amount of gain to apply using a least mean square algorithm and/or a machine learning model.

A reference microphone for detecting noise is located under a first duct. The noise is in the form of a first plane wave in the first duct. A speaker is located on a top of the first duct. Connected to an upper part of the first duct is a second duct including an error microphone. The first plane wave in the first duct passes through an acoustic path and reaches the second duct. The error microphone detects the sound, and the speaker outputs a second plane wave with an opposite phase for canceling the first plane wave.

An active noise reduction earbud and method. The earbud includes a housing comprising an outlet portion that defines a sound outlet, wherein the outlet portion is configured to be located in or proximate the external auditory meatus of a user's ear, a first feedforward microphone configured to develop a first input signal, and a first sound inlet opening in the housing and configured to conduct external sound to be sensed by the first feedforward microphone, wherein the first sound inlet opening is proximate the outlet portion.