In accordance with an embodiment, a method for canceling noise in a vehicle includes receiving noise information from an earphone worn by a user inside the vehicle; generating a compensating signal based on the noise information; and outputting the compensating signal through the earphone and an internal speaker of the vehicle.

In an active noise reducing headphone, a signal processor applies filters and control gains of both the feed-forward and feedback active noise cancellation signal paths. The signal processor is configured to apply first feed-forward filters to the feed-forward signal path and apply first feedback filters to the feedback signal path during a first operating mode providing effective cancellation of ambient sound, and to apply second feed-forward filters to the feed-forward signal path during a second operating mode providing active hear-through of ambient sounds with ambient naturalness.

A method for generating an active noise reduction filter includes: obtaining a physically noise-reduced signal, the physically noise-reduced signal being a signal received by a feedback microphone after a noise signal passes through an earphone, obtaining a mixed signal, the mixed signal being a signal received by the feedback microphone when the same noise signal is played and the earphone plays a through signal in a through state, calculating an input signal according to the mixed signal and the physically noise-reduced signal, performing adaptive filtering on the input signal and the physically noise-reduced signal according to an adaptive filtering algorithm to obtain a transfer function, and generating an active noise reduction filter according to the transfer function.

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.

The technology described in this document can be embodied in a method that includes receiving an input signal captured by one or more sensors associated with an active noise reduction (ANR) headphone, and determining one or more characteristics of a first portion of the input signal. Based on the one or more characteristics of the first portion of the input signal, a gain of a variable gain amplifier (VGA) disposed in an ANR signal flow path can be adjusted, and accordingly, a set of coefficients for a tunable digital filter disposed in the ANR signal flow path can be selected. The method further includes processing a second portion of the input signal in the ANR signal flow path using the adjusted gain and selected set of coefficients to generate a second output signal for the electroacoustic transducer of the ANR headphone.

An ear-mountable listening device includes an array of microphones physically arranged into a ring pattern to capture sounds from an environment and output first audio signals that are representative of the sounds captured by the microphones. A speaker is arranged to emit audio into an ear in response to a second audio signal. Electronics are coupled to the array of microphones and the speaker and configured to capture the sounds with the array of microphones to generate the first audio signals and generate the second audio signal that drives the speaker based upon one or more of the first audio signals.

The overall performance of an ANC system may be improved by configuring the ANC system to perform adaption in the frequency domain. The ANC systems may be configured to update an algorithm of an adaptive filter based, at least in part, on the first input signal, the second input signal, and a feedback signal that is based on an output of the adaptive filter. Updating may include changing parameters of the algorithm based on a SDR based, at least in part, on the first input signal. Updating may also include normalizing a step size and processing at least full band information for the input signal in a frequency domain to generate coefficient values for the algorithm. Updating may also include applying a frequency domain magnitude constraint on adaptive filter coefficients.

One example method includes performing sound quality operations. Microphone arrays are used to cancel background noise and to enhance speech. With arrays at each environment of each user participating in a call, a first microphone array can cancel or suppress background noise and a second array can generate enhanced speech for transmission to other users. Thus, for user, the audio signal output by the user's device includes an anti-noise signal to cancel background noise present in the user's environment and enhanced speech from other users.

A processor is configured to perform headphone playback with a playback audio signal. The processor produces a feedback signal from an internal microphone, compresses the feedback signal according to a variable compressor setting, and determines a context of usage of the headphone, as being one of running or jogging, transportation, and critical listening. In response, the processor changes the variable compressor setting and drives the headphone speaker with the compressed feedback signal combined with the playback audio signal. Other aspects are also described and claimed.

An integrated circuit may include an output for providing an output signal to a transducer including both a source audio signal for playback to a listener and an anti-noise signal for countering the effect of ambient audio sounds in an acoustic output of the transducer, 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. The processing circuit may implement a feedback path comprising a feedback filter having a response that generates a feedback anti-noise signal based on the error microphone signal, the feedback filter comprising a plurality of biquad filters and wherein the anti-noise signal is generated from the feedback anti-noise signal and an event detection and oversight control that detects that an ambient audio event is occurring that could cause the feedback filter to generate an undesirable component in the anti-noise signal, and controls filter coefficients of one or more of the plurality of biquad filters to reduce the undesirable component.