Active noise reduction audio devices and systems

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.

BACKGROUND

The present disclosure generally relates to methods and systems directed to controlling audio devices, such as headphones, with active noise reduction.

SUMMARY

Generally, in one aspect, a method of controlling an Active Noise Reduction (ANR) audio system is provided. The method comprises: generating 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; detecting 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 adjusting 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.

In an aspect, the method further comprises: detecting whether the first wearable audio device is engaged with or removed from a first ear of the user using a first sensor of the first wearable audio device and detecting whether the second wearable audio device is engaged with or removed from a second ear of the user using a second sensor of the second wearable audio device; and automatically adjusting the one or more ANR parameters of the first and second wearable audio device to the first ANR state when both the first and second wearable audio device are detected to be engaged with an ear of the user.

In an aspect, the one or more ANR parameters relate to at least one of a feedback filter, a feedforward filter, and an audio equalization.

In an aspect, the one or more ANR parameters of the second ANR state comprise at least one of: default settings or user-set ANR settings that are input by the user.

In an aspect, the one or more ANR parameters of the first ANR state comprise at least one of: default settings, user-set ANR settings that are input by the user, or a last-used ANR settings.

In an aspect, in the second ANR state, the first and second wearable audio device can be utilized to perform at least one of the following: start an audio signal to be reproduced by the audio system; stop an audio signal from being reproduced by the audio system; pause the audio signal that was being reproduced by the audio system; answer a phone call; decline a phone call; accept a notification; dismiss a notification; and access a voice assistant.

In an aspect, the first and second wearable audio device are arranged to operate in a plurality of ANR states during which the one or more ANR parameters are adjusted using a user interface to increase or decrease noise reduction.

In an aspect, the first sensor of the first wearable audio device and the second sensor of the second wearable audio device comprise at least one of: a gyroscope, an accelerometer, an infrared sensor, a magnetometer, an acoustic sensor, a motion sensor, a piezoelectric sensor, a piezoresistive sensor, a capacitive sensor, and a magnetic field sensor.

Generally, in one aspect, a computer program product comprising a set of non-transitory computer readable instructions stored on a memory and executable by a processor to perform a method for controlling an Active Noise Reduction (ANR) audio system is provided. The set of non-transitory computer readable instructions are arranged to: generate 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; detect 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 adjust 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.

In an aspect, the set of non-transitory computer readable instructions further arranged to: detect whether the first wearable audio device is engaged with or removed from a first ear of the user using a first sensor of the first wearable audio device and detect whether the second wearable audio device is engaged with or removed from a second ear of the user using a second sensor of the second wearable audio device; and automatically adjust the one or more ANR parameters of the first and second wearable audio device to the first ANR state when both the first and second wearable audio device are detected to be engaged with an ear of the user.

In an aspect, the one or more ANR parameters relate to at least one of a feedback filter, a feedforward filter, and an audio equalization.

In an aspect, the one or more ANR parameters of the second ANR state comprise at least one of: default settings or user-set ANR settings that are input by the user.

In an aspect, the first and second wearable audio device are arranged to operate in a plurality of ANR states during which the one or more ANR parameters are adjusted using a user interface to increase or decrease noise reduction.

Generally, in one aspect, an Active Noise Reduction (ANR) audio system comprising a first wearable audio device and a second wearable audio device is provided. The first wearable audio device comprises: a first sensor arranged to determine if the first wearable audio device is engaged with or removed from a first ear of a user. The second wearable audio device comprises: a second sensor arranged to determine if the second wearable audio device is engaged with or removed from a second ear of the user. The audio system comprises a controller arranged to: generate one or more control signals to set one or more ANR parameters of the first and the second wearable audio device to a first ANR state; detect 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 adjust 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.

In an aspect, the controller is further arranged to: detect whether the first wearable audio device is engaged with or removed from the first ear of the user using the first sensor of the first wearable audio device and detecting whether the second wearable audio device is engaged with or removed from the second ear of the user using the second sensor of the second wearable audio device; and automatically adjust the one or more ANR parameters of the first and second wearable audio device to the first ANR state when both the first and second wearable audio device are detected to be engaged with an ear of the user.

In an aspect, the first and second wearable audio device are arranged to operate in a plurality of ANR states during which the one or more ANR parameters are adjusted using a user interface to increase or decrease noise reduction.

In an aspect, the first wearable audio device further comprises a first user interface adapted to receive user input to increase or decrease noise reduction.

In an aspect, the first wearable audio device further comprises a first outer surface, the first outer surface comprising a first touch capacitive sensor.

In an aspect, the controller is arranged within, around, or proximate to the first wearable audio device or the second wearable audio device.

In an aspect, the first sensor of the first wearable audio device and the second sensor of the second wearable audio device comprise at least one of: a gyroscope, an accelerometer, an infrared sensor, a magnetometer, an acoustic sensor, a motion sensor, a piezoelectric sensor, a piezoresistive sensor, a capacitive sensor, and a magnetic field sensor.

These and other aspects of the various illustrations will be apparent from and elucidated with reference to the aspect(s) described hereinafter.

DETAILED DESCRIPTION

In headphones, such as wireless headphones, that have Active Noise Reduction (“ANR”) capability, different ANR settings may provide different levels of noise reduction. The present disclosure provides methods and systems directed to automatically adjusting the ANR parameters that alter noise reduction levels in the headphones based on whether the headphones are engaged with or removed from a user ear. According to an example, the system detects whether one or both of a first headphone and a second headphone are engaged with a user's ear. If both headphones are engaged with a user's ear, then the ANR subsystem automatically adjusts the ANR settings of the two headphones to bring the headphones to a first ANR state with either a default high level of noise reduction, a user-selected level of noise reduction, or the last selected level of noise reduction. If one or both headphones are removed from the ear, both headphones are brought to a second ANR state with lower levels of noise reduction. This enables a user to have lower noise reduction settings in a headphone engaged with the ear after removing the other headphone from the ear, to for example, have a conversation with someone. When both headphones are returned to the ear, the system automatically raises the noise reduction levels to those used in the first ANR state.

ANR subsystems are used for cancelling or reducing unwanted or unpleasant noise. An ANR subsystem can include an electroacoustic system that can be configured to cancel at least some of the unwanted noise (often referred to as primary noise) based on the principle of superposition. This can be done by identifying an amplitude and phase of the primary noise and producing another signal (often referred to as an anti-noise signal) of about equal amplitude and opposite phase. An appropriate anti-noise signal combines with the primary noise such that both are substantially canceled at the location of an error sensor (e.g., canceled to within a specification or acceptable tolerance). In this regard, in the example implementations described herein, “canceling” noise may include reducing the “canceled” noise to a specified level or to within an acceptable tolerance, and does not require complete cancellation of all noise. Noise canceling systems may include feedforward and/or feedback signal paths. A feedforward component detects noise external to the headset (e.g., via an external microphone) and acts to provide an anti-noise signal to counter the external noise expected to be transferred through to the user's ear. A feedback component detects acoustic signals reaching the user's ear (e.g., via an internal microphone) and processes the detected signals to counteract any signal components not intended to be part of the user's acoustic experience. Although described herein as coupled to, or placed in connection with, other systems, through wired or wireless means, it should be appreciated that noise cancelling systems may be independent of any other systems or equipment.

The term “wearable audio device” as used herein is intended to mean a device that fits around, on, in, or near an ear and that radiates acoustic energy into or towards the ear canal. Wearable audio devices are sometimes referred to as headphones, earphones, earpieces, headsets, earbuds or sport headphones, and can be wired or wireless. A wearable audio device includes an acoustic driver to transduce audio signals to acoustic energy. The acoustic driver may be housed in an earcup. While some of the figures and descriptions following may show a single wearable audio device, a wearable audio device may be a single stand-alone unit or one of a pair of wearable audio devices (each including a respective acoustic driver and earcup), one for each ear. A wearable audio device may be connected mechanically to another wearable audio device, for example by a headband and/or by leads that conduct audio signals to an acoustic driver in the wearable audio device. A wearable audio device may include components for wirelessly receiving audio signals. A wearable audio device may include components of an active noise reduction system. Wearable audio devices may also include other functionality such as a microphone so that they can function as a headset. WhileFIG. 1shows an example of an around-ear headset, in other examples the headset may be an in-ear, on-ear, or near-ear headset. In some examples, a wearable audio device may be an open-ear device that includes an acoustic driver to radiate acoustic energy towards the ear canal while leaving the ear open to its environment and surroundings.

Referring now to the drawings,FIG. 1schematically illustrates audio system100. Audio system100generally includes first headphone102, second headphone104, and peripheral device106. First headphone102and second headphone104are both arranged to communicate with peripheral device106and/or communicate with each other. Peripheral device106may be any device capable of establishing a connection with first headphone102and/or second headphone104, either wirelessly through wireless protocols known in the art, or via a wired connection, i.e., via a cable capable of transmitting a data signal from peripheral device106to first headphone102or second headphone104. In one example, first headphone102and second headphone104are in ear or on ear earbuds each arranged to communicate wirelessly with a peripheral device106. In one example, peripheral device106is a smartphone having a computer executable application installed thereon such that the connection between peripheral device106, first headphone102and/or second headphone104can be mutually established using a user interface on peripheral device106.

FIG. 2Aillustrates first headphone102. First headphone102includes a housing, which further includes first driver108, which is an acoustic transducer for conversion of, e.g., an electrical signal, into an audio signal that the user may hear, and (referring toFIG. 3A) first antenna110. The first audio signal may correspond to data related to at least one digital audio file, which can be streamed over a wireless connection to peripheral device106or first headphone102, stored in first memory112(discussed below), or stored in the memory of peripheral device106. First antenna110is arranged to send and receive wireless communication information from, e.g., second headphone104or peripheral device106. As an example, first headphone102and second headphone104are each capable of wireless communication with a peripheral device106. First headphone102includes a controllable ANR subsystem. First headphone102includes one or more microphones, such as a first feedforward microphone114and/or a first feedback microphone116. The first feedforward microphone114may be configured to sense acoustic signals external to the first headphone102when worn, e.g., to detect acoustic signals in the surrounding environment before they reach the user's ear. The feedback microphone116may be configured to sense acoustic signals internal to an acoustic volume formed with the user's ear when the first headphone102is worn, e.g., to detect the acoustic signals reaching the user's ear. In various examples, one or more drivers may be included in a headphone, and a headphone may in some cases include only a feedforward microphone or only a feedback microphone, or multiple feedforward and/or feedback microphones. Returning toFIG. 2A, the housing further includes first outer surface115having a sensor arranged thereon. In one example, the sensor on first outer surface115of first headphone102is a touch capacitive sensor, e.g., first touch capacitive sensor117. First touch capacitive sensor117is arranged to receive at least one user input corresponding to at least one first user control setting119of first set of user control settings128discussed with reference toFIG. 3A. At least one user input can include a swipe gesture (e.g., movement across first touch capacitive sensor117), a single-tap, a double-tap (tapping at least two times over a predetermined period of time), triple-tap (tapping at least three times over a predetermined period of time) or any other rhythmic cadence/interaction with first touch capacitive sensor117. It should also be appreciated that at least one user input could be an input from a sensor such as a gyroscope or accelerometer, e.g., when user U removes first headphone102from ear E, the gyroscope or accelerometer may measure a specified rotation, acceleration, or movement, indicative of user U removing the first headphone102from ear E. Additionally, first headphone102may also include first sensor118in order to detect proximity to or engagement with ear E of user U. Although shown inFIG. 2Aas being arranged on an ear tip of first headphone103, first sensor118could alternatively be arranged on or within the housing of first headphone102. First sensor118can be any of: a gyroscope, an accelerometer, a magnetometer, an infrared (IR) sensor, an acoustic sensor (e.g., a microphone or acoustic driver), a motion sensor, a piezoelectric sensor, a piezoresistive sensor, a capacitive sensor, a magnetic field sensor, or any other sensor known in the art capable of determining whether first headphone102is proximate to, engaged with, within, or removed from ear E of user U.

Referring toFIG. 3A, first headphone102further includes first controller120. In an example, first controller120includes at least first processor122and first memory112. The first processor122and first memory112of first controller120are arranged to receive, send, store, and execute any of a plurality of ANR parameters125, a first set of ANR parameters124, and/or a second set of ANR parameters126which may relate to a feedback filter, a feedforward filter, or audio equalization, based on a signal from the first feedforward microphone114and/or first feedback microphone116. The first processor122and first memory112of first controller120are arranged to receive, send, store, and execute at least one first user control setting119of a first set of user control settings128. In an example, first set of user control settings128can include settings such as, but not limited to: increase or decrease volume of the audio signal being reproduced by the audio system100; increase or decrease noise reduction by an controller; start/play/stop/pause the audio signal being reproduced by the audio system100; answer or decline a phone call; accept or dismiss a notification; and access a voice assistant, such as Alexa, Google Assistant, or Siri. The functions of the controller120may be performed by one or more separate controllers, which may be arranged to communicate with and operate in conjunction with each other. As an example, one controller may be arranged to receive, send, store, and execute any of a plurality of ANR parameters125, a first set of ANR parameters124, and/or a second set of ANR parameters126, and a separate controller may be arranged to receive, send, store, and execute at least one first user control setting119of a first set of user control settings128.

FIG. 2Billustrates second headphone104. Second headphone104also includes a housing, which further includes second driver130arranged to reproduce a second audio signal and (referring toFIG. 3B) second antenna132. The second audio signal may correspond to data related to at least one digital audio file which can be streamed over a wireless connection to first headphone102or second headphone104, stored in second memory134(discussed below), or stored in the memory of peripheral device106. Second antenna132is arranged to send and receive wireless communication information from, e.g., first headphone102or peripheral device106. As an example, first headphone102and second headphone104are each capable of wireless communication with a peripheral device106. Second headphone104also includes a controllable ANR subsystem. Second headphone104includes one or more microphones, such as a second feedforward microphone136and/or a second feedback microphone138. In various examples, one or more drivers may be included in a headphone, and a headphone may in some cases include only a feedforward microphone or only a feedback microphone, or multiple feedforward and/or feedback microphones. In one example, the sensor on second outer surface135of second headphone104is a touch capacitive sensor, e.g., second touch capacitive sensor137. Second touch capacitive sensor137is arranged to receive at least one user input corresponding to at least one second user control setting139of second set of user control settings146discussed below. As discussed above with respect to first headphone102, the at least one user input can include a swipe gesture (e.g., movement across second touch capacitive sensor137), a single-tap, a double-tap (tapping at least two times over a predetermined period of time), triple-tap (tapping at least three times over a predetermined period of time) or any other rhythmic cadence/interaction with second touch capacitive sensor137. It should also be appreciated that at least one user input could be an input from a sensor such as a gyroscope or accelerometer, e.g., when user U removes second headphone104from ear E, the gyroscope or accelerometer may measure a specified rotation, acceleration, or movement, indicative of user U removing the second headphone104from ear E. Additionally, second headphone104may also include second sensor140in order to detect proximity to or engagement with ear E of user U. Although shown inFIG. 2Bas being arranged on an ear tip of second headphone104, second sensor140could alternatively be arranged on or within the housing of second headphone104. Second sensor140can be any of: a gyroscope, an accelerometer, a magnetometer, an infrared (IR) sensor, an acoustic sensor (e.g., a microphone or acoustic driver), a motion sensor, a piezoelectric sensor, a piezoresistive sensor, a capacitive sensor, a magnetic field sensor, or any other sensor known in the art capable of determining whether second headphone104is proximate to, engaged with, within, or removed from ear E of user U.

Referring toFIG. 3B, second headphone104further includes second controller142. In an example, second controller142includes at least second processor144and second memory134. The second processor144and second memory134of second controller142are arranged to receive, send, store, and execute any of a plurality of ANR parameters125, a first set of ANR parameters124, and/or a second set of ANR parameters126which may relate to a feedback filter, a feedforward filter, and an audio equalization, based on a signal from a second feedforward microphone136and/or second feedback microphone138. The second processor144and second memory134of second controller142are also arranged to receive, send, store, and execute at least one second user139control setting of a second set of user control settings146. The functions of the controller142may be performed by one or more separate controllers, which may be arranged to communicate with and operate in conjunction with each other. As an example, one controller may be arranged to receive, send, store, and execute any of a plurality of ANR parameters125, a first set of ANR parameters124, and/or a second set of ANR parameters126, and a separate controller may be arranged to receive, send, store, and execute at least one second user control setting139of a second set of user control settings146. As another example, only one of the first controller124or the second controller142may be present in both the first headphone102and the second headphone104. In that case, the controller which is present in the first headphone or second headphone may detect whether one or both of the first headphone and the second headphone are engaged with or removed from the ear of a user and adjust ANR parameters in one or both headphones.

FIG. 4illustrates an exemplary system and method of processing microphone signals, for example in the first headphone102, to reduce noise reaching the ear E of user U.FIG. 4presents a simplified schematic diagram to highlight features of a noise reduction system. Various examples of a complete system may include amplifiers, analog-to-digital conversion (ADC), digital-to-analog conversion (DAC), equalization, sub-band separation and synthesis, and other signal processing or the like. In some examples, a playback signal148, p(t), may be received to be rendered as an acoustic signal by the first driver108. The first feedforward microphone114may provide a feedforward signal150that is processed by a feedforward processor122A of the first processor122, having a feedforward transfer function156, Kff, to produce a feedforward anti-noise signal152. The first feedback microphone116may provide a feedback signal154that is processed by a feedback processor122B of the first processor122, having a feedback transfer function158, Kfb, to produce a feedback anti-noise signal160. In various examples, any of the playback signal148, the feedforward anti-noise signal152, and/or the feedback anti-noise signal160may be combined, e.g., by a combiner162, to generate a driver signal164, d(t), to be provided to the first driver108. In various examples, any of the playback signal148, the feedforward anti-noise signal152, and/or the feedback anti-noise signal160may be omitted and/or the components necessary to support any of these signals may not be included in a particular implementation of a system. Although the above example is provided on an ANR subsystem of the first headphone102, the second headphone104is capable of providing noise cancellation and includes second controller142, second processor144, second feedforward microphone136, and feedback microphone138, and second driver124to perform noise reduction.

Different ANR settings providing different levels of noise reduction may be desirable to a user based on user preferences, system settings, and operational mode. For example, a user may desire more noise reduction based on environmental conditions and desire ANR settings that are more aggressive and cancel more noise and/or noise in a wider range of frequencies. Another user may desire less noise reduction, for example in order to hear more noise from the external environment, and desire less aggressive ANR settings that cancel less noise and/or noise in a narrower range of frequencies. To achieve different levels of noise reduction, different ANR parameters may be varied, for example, feedback filter settings, e.g., the gain and/or phase associated with a filter applied to a feedback microphone, e.g. first feedback microphone116or second feedback microphone138, of the controllable ANR subsystem; feedforward filter settings, e.g., the gain and/or phase associated with a filter applied to a feedforward microphone, e.g. first feedforward microphone114or second feedforward microphone136, of the ANR subsystem; audio equalization settings, and various other parameters of the noise reduction system, such as, for example, a driver signal amplitude (e.g., mute, reduce, or limit the driver signal164).

During operation of audio system100, first headphone102and/or second headphone104can pair (e.g. using known Bluetooth, Bluetooth Low Energy, or other wireless protocol pairing) or connect with peripheral device106, e.g., a smartphone. An audio stream may be established between peripheral device106, first headphone102, and second headphone104. The audio stream can include data relating to an audio file streamed over a wireless connection or a stored audio file. An ANR subsystem may be operational on the first headphone102and second headphone104having automatic ANR settings, which are set based on whether the headphones are engaged with or removed from a user's ear. The first sensor118and the second sensor140detect whether the first headphone102and the second headphone104, respectively, are engaged with or removed from a user's ear. When both the first headphone102and the second headphone104are engaged with an ear of the user, the ANR settings of both headphones102/104are automatically adjusted to a first ANR state with a first set of ANR parameters, which may include one of: a default level of noise reduction, which may be a higher noise reduction setting to block unwanted noise from the environment; a user-selected level of noise reduction; or the last selected level of noise reduction. If a user removes one headphone102/104from the ear, the ANR settings are automatically adjusted by the first controller120and/or the second controller142to bring both headphones102/104to a second ANR state with a second set of ANR parameters, which may permit more of the environment to pass through the headphones102/104. In this second ANR state, ANR may be lower than in the first ANR state at least at some frequencies, for example the frequencies that typically contain human speech sounds (e.g., 140 Hz to 5 kHz). Examples of technologies that can be used in the second ANR state to permit more of the environment to pass through the headphones102/104are described in U.S. Pat. Nos. 8,798,283; 9,949,017; and 10,096,313, each of which is incorporated herein by reference in its entirety. If the user has only removed the first headphone102from the ear, for example, to engage in a conversation with someone, the noise cancellation of the second headphone104is modified (as described above) to allow the conversation to be heard through the second headphone104. In some examples, the noise cancellation of the first headphone102is also modified in the same manner. As another example, during the second ANR state, the headphones could take additional actions to make it easier for noise from the environment to be heard. For example, the volume on audio content may be reduced, audio content may be paused, audio content or phone conversation may be muted, or additional microphones on the headphone still engaged with a user's ear may be enabled which focus on environmental noise. When both headphones102/104are removed from the ears, the first controller120or second controller142also automatically adjusts the ANR parameters of both headphones102/104to bring both headphones102/104to the second ANR state. If a user then returns one or both headphones102/104to the ears, for example, after finishing a conversation, then the controller (either the first controller120, the second controller142, or both controllers) then automatically brings the headphones102/104to the first ANR state, which in some examples has greater noise reduction and can block more noise from the environment.

As an example, the ANR parameters of the first state and the second state may be default settings which are preprogrammed into the headphones102/104, for example, during the manufacturing and assembly of the headphones. As another example, the ANR parameters may be adjustable so that a user can adjust the ANR parameters for the first ANR state and/or the second ANR state so that the level of noise reduction when the headphones operate in those states, for example, based on whether both headphones102/104are inserted in both ears, is adjusted. For example, a user may want less noise reduction when the headphones are operating in the second state, so that, as an example, the user can hear certain environmental noise like car horns or emergency vehicle sirens, or a desired amount of conversation through the headphone that is still in the user's ear. As another example, a user may desire less or more noise reduction in the first ANR state, for example, to be able to cancel unwanted environmental noise, e.g., airplane noise. The user may be able to adjust the ANR parameters of the first and/or second ANR state. As another example, the audio system100may be capable of operating in a plurality of ANR states, with a plurality of ANR parameters125, where additional ANR states are available to a user in addition to the first ANR state and the second ANR state. These states may be preprogramed into the audio system or adjustable by the user. As an example, the user may be able to increase or decrease noise reduction using a user interface, e.g., first touch capacitive sensor117and/or second touch capacitive sensor137. Systems with multiple ANR states are described in the applications that have been incorporated by reference herein.

FIG. 5is a flow-chart illustrating the steps of a method for controlling an audio system100according to aspects of the present disclosure. The method200includes the steps of: generating one or more control signals, using an Active Noise Reduction (ANR) controller120/142, to set one or more ANR parameters of a first headphone102and a second headphone104to a first ANR state (step210); detecting, at a first sensor118of the first headphone102, whether the first headphone102is engaged with or removed from a first ear of a user (step220); detecting, at a second sensor140of the second headphone104, whether the second headphone104is engaged with or removed from a second ear of the user (step230); automatically adjusting the one or more ANR parameters of the first headphone102and the second headphone104to a second ANR state when either the first headphone102or the second headphone104, 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 (step240); automatically adjusting the one or more ANR parameters of the first headphone102and second headphone104to the first ANR state when both the first headphone102and second headphone104are detected to be engaged with an ear of the user (step250).

A computer program product for performing a method for controlling an audio system100can have a set of non-transitory computer readable instructions. The set of non-transitory computer readable instructions can be stored and executed on a memory112/134and a processor122/144of a first headphone102and second headphone104(shown inFIGS. 2A and 2B). The set of non-transitory computer readable instructions can be arranged to: generate one or more control signals, using an Active Noise Reduction (ANR) controller120/142, to set one or more ANR parameters of a first headphone102and a second headphone104to a first ANR state; detect, at a first sensor118of the first headphone102, whether the first headphone102is engaged with or removed from a first ear of a user; detect, at a second sensor140of the second headphone104, whether the second headphone104is engaged with or removed from a second ear of the user; automatically adjust the one or more ANR parameters of the first headphone102and the second headphone104to a second ANR state when either the first headphone102or the second headphone104, 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; automatically adjust the one or more ANR parameters of the first headphone102and second headphone104to the first ANR state when both the first headphone102and second headphone104are detected to be engaged with an ear of the user.

The above-described examples of the described subject matter can be implemented in any of numerous ways. For example, some aspects may be implemented using hardware, software or a combination thereof. When any aspect is implemented at least in part in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single device or computer or distributed among multiple devices/computers.

Other implementations are within the scope of the following claims and other claims to which the applicant may be entitled.