An integrated circuit for implementing at least a portion of a personal audio device may include an output for providing a signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer, a reference microphone input for receiving a reference microphone signal indicative of the ambient audio sounds, an error microphone input for receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer, and a processing circuit configured to implement an adaptive infinite impulse response filter having a response that generates the anti-noise signal to reduce the presence of the ambient audio sounds at the error microphone and implement a coefficient control block that shapes the response of the adaptive infinite impulse response filter in conformity with the error microphone signal by generating coefficients that determine the response of the adaptive infinite impulse response filter in order to minimize the ambient audio sounds at the error microphone, wherein the coefficient control block selects the coefficients from a library of filter entries, each filter entry of the library of filter entries defining a respective response for the adaptive infinite impulse response filter.

A system and method for quieting unwanted sound. As a non-limiting example, various aspects of this disclosure provide a system and method, for example implemented in a premises-based or home audio system, for quieting unwanted sound at a particular location.

The present invention provides an improved noise separation hybrid type ANC system, which includes a reference audio receiving device, an error audio receiving device, an audio output device, and an audio processing device. The audio processing device includes a feed-forward noise cancellation filter module, a feedback noise cancellation filter module, a mixer, a noise shaper, a first infinite impulse response filter, and a second infinite impulse response filter. When the noise bandwidth detector detects irregular noise, it adjusts the coefficient of the first infinite impulse response filter to set it as a low-pass filter; when regular noise is detected, the coefficient of the second infinite impulse response filter is adjusted to set it as a band-pass filter.

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 time indication is exchanged based on detection of a first condition of a microphone signal. 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.

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 electronic system includes a fan module, an embedded controller, an error microphone, an active noise cancellation controller, and a micro speaker module. The error microphone is configured to output an error signal by detecting the noise level during the operation of the electronic system. According to the error signal and the fan information provided by the embedded controller, the active noise cancellation controller calculates the narrow-band noises associated with the actual single-blade fundamental frequency noise and the actual BPF fundamental frequency noise generated by the fan module, and drives the micro speaker module accordingly for providing a noise cancellation signal. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises generated during the operation of the electronic system.

An audio system for an ear mountable playback device comprises a compensation filter configured to generate a third compensation signal by applying filter operations to an audio signal, and an error compensation unit configured to generate a compensated error signal on the basis of the third compensation signal and a disturbed audio signal from an error microphone. The audio system further comprises a first noise filter configured to be adapted based on the compensated error signal, and a detection unit configured to estimate the acoustic leakage condition on the basis of the first noise filter or of the disturbed audio signal and an audio output signal. The compensation filter is configured to be adapted based on the acoustic leakage condition.

An active control method for filtered reference affine projection sign algorithm based on variable step size includes: S1, acquiring impulse noise signals and transmitting the signals to control filters; S2, transmitting the impulse noise signals by the control filters to post filters; S3, generating cancellation signals of the impulse noise signals by the post filters according to the impulse noise signals and internal active control algorithms, and transmitting the cancellation signals to a speaker; S4, sending out the cancellation signal by the speaker to superimpose with the impulse noise signals to cancel the impulse noise signal. A convex combination structure and a variable step size strategy are adopted, and by adjusting step size coefficients in the control filter structure, convergence speed of algorithm is controlled, contradiction between convergence speed and steady-state error is coordinated, convergence performance of control algorithm to impulse noises is improved, and impulse noises are effectively controlled.

An active noise cancelling system (20) comprising: an earphone (8′) comprising: an electro-acoustic driver (11); and at least one sensing microphone (12, 13); tunable active noise cancelling circuitry (7) operative to receive a signal from the at least one sensing microphone (12, 13), the tunable active noise cancelling circuitry (7) being pre-configured in a standard tuning for a reference ear and comprising at least one noise-control filter (14, 15); and a tuning module (24) operative to configure the earphone (8′) for an individual wearer by: comparing acoustic coupling of the earphone (8′) to the individual wearer's ear with acoustic coupling to the reference ear to determine a deviation in acoustic coupling; and using the determined deviation in acoustic coupling to modify the tunable active noise cancelling circuitry (7) by a predetermined degree based on the determined deviation in acoustic coupling.

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.