Abstract: An apparatus includes a noise reduction headphone comprising one or more microphones and an acoustic transducer, the one or more microphones configured to generate an input signal; and a controller comprising one or more processing devices, the controller configured to: process the input signal through one or more noise reduction filters to generate a noise-reduction signal, compare the input signal to an estimate of ambient noise to determine if the energy of the input signal is greater than the estimate of ambient noise, wherein if the energy of the input signal is greater than the estimate of ambient noise by a predetermined amount, a change in the noise reduction signal is suppressed; and generate an output signal, the output signal comprising, at least in part, the noise-reduction signal, wherein the acoustic transducer is configured to produce an acoustic output in accordance with the output signal.

Abstract: A method for detecting and mitigating parasitic oscillation in a headphone equipped with an active noise reduction (ANR) system. A fundamental frequency of a microphone signal is determined from a microphone of the ANR system and an amplitude of the determined fundamental frequency is compared to a threshold level to determine parasitic oscillation. If parasitic oscillation is determined, then the microphone signal is altered to mitigate the parasitic oscillation.

Abstract: A method and system directed to controlling Active Noise Reduction (ANR) audio devices with active noise reduction. The system sets one or more ANR parameters of a first and a second wearable audio device to a first ANR state; detects that the first wearable audio device is removed from a first ear of a user; and automatically adjusts the one or more ANR parameters of the second wearable audio device to a second ANR state when the first wearable audio device is removed from the ear of the user, wherein the second ANR state comprises a reduction in a level of ANR compared to the first ANR state.

Abstract: A method and system directed to controlling audio devices with active noise reduction. The system detects a first instability condition in a first headphone based on one or more parameters; alters a parameter of the one or more parameters; and detects a second audio instability condition in the first headphone based on the altered parameter of the one or more parameters. The first and second audio instability conditions are related to audio feedback.

Abstract: A method for detecting and mitigating parasitic oscillation in a headphone equipped with an active noise reduction (ANR) system. A fundamental frequency of a microphone signal is determined from a microphone of the ANR system and an amplitude of the determined fundamental frequency is compared to a threshold level to determine parasitic oscillation. If parasitic oscillation is determined, then the microphone signal is altered to mitigate the parasitic oscillation.

Abstract: A method and system directed to controlling audio devices with active noise reduction. The system detects an instability condition in a first headphone; generates one or more control signals to adjust one or more ANR parameters of the first headphone using a first controller, wherein the one or more ANR parameters are adjusted to change the first headphone from a first ANR state to a second ANR state to mitigate the instability condition; and synchronizes the one or more ANR parameters of the first headphone with second headphone. In an example, the system returns the first headphone to the first ANR state after detecting that the first headphone was removed from an ear of a user at the first time and detecting that the first headphone was engaged with the ear at the second time.

Abstract: A system for detecting parasitic oscillation in a wearable audio device that includes an electro-acoustic transducer that is configured to develop sound for a user, a housing that holds the transducer, at least one of a feedforward microphone that is configured to detect sound outside of the housing and output a feedforward microphone signal and a feedback microphone that is configured to detect sound inside of the housing and output a feedback microphone signal, and an opening in the housing that emits sound pressure from the transducer. The system includes a parasitic oscillation detector that is configured to determine a fundamental frequency of at least one of the feedforward and feedback microphone signals and compare an amplitude of the determined fundamental frequency to a threshold level, to determine parasitic oscillation.

Abstract: A method performed by an audio output device is provided for detecting instabilities and taking mitigating actions. Specifically, an A-weighted dBA level of a raw feedback signal exceeding a threshold level trigger, at least, muting the driver. The described methods apply to detecting instabilities across a broad frequency spectrum.

Abstract: A system for detecting parasitic oscillation in a wearable audio device that includes an electro-acoustic transducer that is configured to develop sound for a user, a housing that holds the transducer, at least one of a feedforward microphone that is configured to detect sound outside of the housing and output a feedforward microphone signal and a feedback microphone that is configured to detect sound inside of the housing and output a feedback microphone signal, and an opening in the housing that emits sound pressure from the transducer. The system includes a parasitic oscillation detector that is configured to determine a fundamental frequency of at least one of the feedforward and feedback microphone signals and compare an amplitude of the determined fundamental frequency to a threshold level, to determine parasitic oscillation.

Abstract: Technology described in this document can be embodied in an earpiece of an active noise reduction (ANR) device. The earpiece includes a plurality of microphones, wherein each of the plurality of microphones is usable for capturing ambient audio to generate input signals for both an ANR mode of operation and a hear-through mode of operation of the ANR device. The earpiece further includes a controller configured to: process a first subset of microphones from the plurality of microphones to generate input signals for the ANR mode of operation and process a second subset of microphones from the plurality of microphones to generate input signals for the hear-through mode of operation. The second subset of microphones excludes a first microphone from the plurality of microphones located closest to a noise pathway of the earpiece.

Abstract: Technology described in this document can be embodied in an earpiece of an active noise reduction (ANR) device. The earpiece includes a plurality of microphones, wherein each of the plurality of microphones is usable for capturing ambient audio to generate input signals for both an ANR mode of operation and a hear-through mode of operation of the ANR device. The earpiece further includes a controller configured to: process a first subset of microphones from the plurality of microphones to generate input signals for the ANR mode of operation, process a second subset of microphones from the plurality of microphones to generate input signals for the hear-through mode of operation, detect that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation, and in response to the detection, process the input signals from the second subset of microphones without using input signals from the particular microphone.

Abstract: A system for detecting feedforward instability in a wearable audio device. The audio device includes an electro-acoustic transducer that is configured to develop sound for a user, a housing that holds the transducer, a feedforward microphone that is configured to detect sound outside of the housing and output a microphone signal, and an opening in the housing that emits sound pressure from the transducer that can reach the microphone. A feedforward instability detector is configured to apply two filters to the microphone signal. A first filter passes more energy in a frequency band than does a second filter, to develop a filtered signal. The filtered signal is compared to the microphone signal outside of the frequency band, to develop a comparison signal that is indicative of feedforward instability in the frequency band.

Abstract: A system for detecting feedforward instability in a wearable audio device. The audio device includes an electro-acoustic transducer that is configured to develop sound for a user, a housing that holds the transducer, a feedforward microphone that is configured to detect sound outside of the housing and output a microphone signal, and an opening in the housing that emits sound pressure from the transducer that can reach the microphone. A feedforward instability detector is configured to apply two filters to the microphone signal. A first filter passes more energy in a frequency band than does a second filter, to develop a filtered signal. The filtered signal is compared to the microphone signal outside of the frequency band, to develop a comparison signal that is indicative of feedforward instability in the frequency band.

Abstract: A method and system directed to controlling audio devices with active noise reduction. The system detects an instability condition in a first headphone; generates one or more control signals to adjust one or more ANR parameters of the first headphone using a first controller, wherein the one or more ANR parameters are adjusted to change the first headphone from a first ANR state to a second ANR state to mitigate the instability condition; and synchronizes the one or more ANR parameters of the first headphone with second headphone. In an example, the system returns the first headphone to the first ANR state after detecting that the first headphone was removed from an ear of a user at the first time and detecting that the first headphone was engaged with the ear at the second time.

Abstract: A method and system directed to controlling audio devices with active noise reduction. The system detects an instability condition in a first headphone; generates one or more control signals to adjust one or more ANR parameters of the first headphone using a first controller, wherein the one or more ANR parameters are adjusted to change the first headphone from a first ANR state to a second ANR state to mitigate the instability condition; and synchronizes the one or more ANR parameters of the first headphone with second headphone. In an example, the system returns the first headphone to the first ANR state after detecting that the first headphone was removed from an ear of a user at the first time and detecting that the first headphone was engaged with the ear at the second time.

Abstract: A method and system directed to controlling Active Noise Reduction (ANR) audio devices with active noise reduction. The system generates one or more control signals, using a controller, to set one or more ANR parameters of a first and a second wearable audio device to a first ANR state; detects at least one of: whether the first wearable audio device is engaged with or removed from a first ear of a user, using a first sensor of the first wearable audio device; or whether a second wearable audio device is engaged with or removed form a second ear of a user, using a second sensor of the second wearable audio device; and automatically adjusts the one or more ANR parameters of the first and/or second wearable audio device to a second ANR state when either the first wearable audio device or the second wearable audio device, or both, are removed from an ear of the user, wherein the second ANR state comprises a reduction in a level of ANR at least at some frequencies compared to the first ANR state.

Abstract: Technology described in this document can be embodied in an earpiece of an active noise reduction (ANR) device. The earpiece includes a plurality of microphones, wherein each of the plurality of microphones is usable for capturing ambient audio to generate input signals for both an ANR mode of operation and a hear-through mode of operation of the ANR device. The earpiece further includes a controller configured to: process a first subset of microphones from the plurality of microphones to generate input signals for the ANR mode of operation, process a second subset of microphones from the plurality of microphones to generate input signals for the hear-through mode of operation, detect that a particular microphone of the second subset is acoustically coupled to an acoustic transducer of the ANR device in the hear-through mode of operation, and in response to the detection, process the input signals from the second subset of microphones without using input signals from the particular microphone.

Abstract: A method and system directed to controlling Active Noise Reduction (ANR) audio devices with active noise reduction. The system generates one or more control signals, using a controller, to set one or more ANR parameters of a first and a second wearable audio device to a first ANR state; detects at least one of: whether the first wearable audio device is engaged with or removed from a first ear of a user, using a first sensor of the first wearable audio device; or whether a second wearable audio device is engaged with or removed form a second ear of a user, using a second sensor of the second wearable audio device; and automatically adjusts the one or more ANR parameters of the first and/or second wearable audio device to a second ANR state when either the first wearable audio device or the second wearable audio device, or both, are removed from an ear of the user, wherein the second ANR state comprises a reduction in a level of ANR at least at some frequencies compared to the first ANR state.

Abstract: A method and system directed to controlling audio devices with active noise reduction. The system detects an instability condition in a first headphone; generates one or more control signals to adjust one or more ANR parameters of the first headphone using a first controller, wherein the one or more ANR parameters are adjusted to change the first headphone from a first ANR state to a second ANR state to mitigate the instability condition; and synchronizes the one or more ANR parameters of the first headphone with second headphone. In an example, the system returns the first headphone to the first ANR state after detecting that the first headphone was removed from an ear of a user at the first time and detecting that the first headphone was engaged with the ear at the second time.

Abstract: A method and system directed to controlling Active Noise Reduction (ANR) audio devices with active noise reduction. The system generates one or more control signals, using a controller, to set one or more ANR parameters of a first and a second wearable audio device to a first ANR state; detects at least one of: whether the first wearable audio device is engaged with or removed from a first ear of a user, using a first sensor of the first wearable audio device; or whether a second wearable audio device is engaged with or removed form a second ear of a user, using a second sensor of the second wearable audio device; and automatically adjusts the one or more ANR parameters of the first and/or second wearable audio device to a second ANR state when either the first wearable audio device or the second wearable audio device, or both, are removed from an ear of the user, wherein the second ANR state comprises a reduction in a level of ANR at least at some frequencies compared to the first ANR state.