An audio system for an ear mountable playback device comprises a speaker, an error microphone predominantly sensing sound being output from the speaker and a feed-forward microphone predominantly sensing ambient sound. The audio system further comprises a voice activity detector which is configured to record a feed-forward signal from the feed-forward microphone. Furthermore, an error signal is recorded from the error microphone. A detection parameter is determined as a function of the feed-forward signal and the error signal. The detection parameter is monitored and a voice activity state is set depending on the detection parameter.

Provided is an acoustic reproduction apparatus, including a first microphone to be used for noise cancellation processing using a feedback scheme, a second microphone including a sound collection surface in a direction different from a direction of a sound collection surface of the first microphone and to be used for noise cancellation processing using the feedback scheme, and an acoustic signal processing unit configured to generate a noise-cancelling signal using a first sound collection signal collected by the first microphone and a second sound collection signal collected by the 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.

Embodiments include a method and noise cancelling system for cancelling noise in a vehicle by operating at least one noise cancelling means in a first mode of operation to output a noise cancelling signal; receiving at least one input indicative of a state of the vehicle; determining if noise cancelling error conditions are present based on the at least one received input indicative of a state of the vehicle; and operating at least one noise cancelling means in a second mode of operation if noise cancelling error conditions are determined as present.

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.

A cooperative control unit is configured to cause a muffled sound control signal processing unit to start feedforward signal processing, and set, when a secondary path filter has converged, a narrow band noise control signal processing unit to the converged secondary path filter and cause the narrow band noise control signal processing unit to start feedback signal processing.

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.

The present disclosure presents a feedback active noise control system and strategy with online secondary-path modeling, and belongs to the technical field of active noise control. The linear prediction subsystem takes the residual noise as its input and separates the remaining sinusoidal noise from the broadband noise. The remaining sinusoidal noise is used effectively not only to update the controller but also to scale the auxiliary noise, while the broadband noise serves as a desired input of online secondary-path modeling subsystem. In this way, the coupling between the controller and the online secondary-path modeling subsystem is significantly mitigated, leading to both faster convergence and improved noise reduction performance. A practical scheme for refreshing the entire system is also developed to enhance its robustness against even abrupt changes with the secondary path or the primary noise. The present disclosure enhances the applicability of feedback active noise control in practical applications.

In at least one embodiment, an active noise cancellation system. The system includes a first controller, a data bus, and a second controller. The first controller receives first information from a plurality of noise sensing devices and second information from an audio system. The first controller employs a time division multiplexing scheme to generate a multiplexed stream of data including the first information and the second information. The data bus transmits the multiplexed stream of data on a single data channel. The second controller receives the multiplexed stream of data on the single data channel and separates the first information from the second information on the multiplexed stream of data to perform ANC functionality.