Patent Description:
Wearable audio output devices having noise cancelling capabilities have steadily increased in popularity. Modern headphones with ANR (sometimes referred to as active noise cancelling (ANC)) capabilities attenuate sounds external to the headphones to provide an immersive audio experience to the user. However, a user may want to selectively set a level of attenuation of external sounds to suit particular use cases. For instance, there may be certain situations when a user wearing the headphones with ANR turned on may want or need to set the ANR to a low level to increase situational awareness. On the other hand, there may be situations when the user may want the ANR set to a high level to attenuate external sounds. While most ANR audio devices allow the user to manually turn ANR on or turn off, or even manually set a level of the ANR, this does not provide an optimal user experience. Accordingly, methods for automatic selective ANR control as well as apparatuses and systems configured to implement these methods are desired.

<CIT>, <CIT> and <CIT> disclose prior art methods and systems.

The present invention relates to a method and a wearable audio output device according to the independent claims. Advantageous embodiments are set forth in dependent claims of the appended set of claims.

All examples and features mentioned herein can be combined in any technically possible manner.

Aspects of the present disclosure provide a method for controlling external noise in a wearable audio output device according to claim <NUM>.

In an aspect, detecting the detected speech signal does not include voice commands for the VP A includes determining at least one word uttered by the user within a given time period after detecting the WUW is a voice command for the VPA.

In an aspect, detecting a speech signal from a user wearing the wearable audio output device includes at least one of detecting that a sound signal including the speech signal is emanating from a general direction of the user's mouth, detecting that the sound signal includes the speech signal using voice activity detection (VAD); detecting that the user's mouth is moving; or detecting an identity of the user based on the speech signal.

In an aspect, modifying a level of the active noise reduction includes temporarily reducing the level of the active noise reduction for a configured time period.

In an aspect, the method further includes resetting, after expiration of the time period, the level of the active noise reduction to at least one of a configured value or a value at which the level was set before the modification.

In an aspect, the method further includes lowering a volume of audio output by at least one speaker of the audio output device.

In an aspect, the method further includes when the user is participating in a phone conversation using the audio output device and when the active noise reduction is at the modified level, detecting that a voice stream of the user related to the phone conversation as received from the microphone of the audio output device is set to unmute by the user; and in response, resetting the level of the active noise reduction to at least one of a configured value or a value at which the level was set before the reduction.

Aspects of the present disclosure provide an audio output device according to claim <NUM>.

In an aspect, the at least one processor is configured to detect the detected speech signal does not include voice commands for the VPA by determining at least one word uttered by the user within a given time period after detecting the WUW is a voice command for the VPA.

In an aspect, the at least one processor is configured to detect a speech signal from a user wearing the wearable audio output device by at least one of detecting that a sound signal including the speech signal is emanating from a general direction of the user's mouth; detecting that the sound signal includes the speech signal using voice activity detection (VAD); detecting that the user's mouth is moving; or detecting an identity of the user based on the speech signal.

Two or more features described in this disclosure, including those described in this summary section, may be combined to form implementations not specifically described herein.

Wearable audio output devices with ANR capability (e.g., ANR headphones) help users enjoy high quality music and participate in productive voice calls by attenuating sounds including noise external to the audio output devices. However, ANR headphones acoustically isolate the user from the world making it difficult for the user to interact with other people in the vicinity of the user. Thus, when the user wearing the headphones with ANR turned on desires to speak with another person, the user either has to manually lower the level of ANR (e.g., by using a button on the headphones) or has to remove the headphones fully or partially from its regular listening position. This does not provide an optimal experience to the user. Additionally, removing the headphones from its listening position does not allow the user to listen to audio (e.g., music playback or a conference call) while simultaneously speaking to another person.

Aspects of the present disclosure discuss techniques for automatically controlling an ANR level of a wearable audio output device (e.g., temporarily interrupt or lower the ANR level) to enable the user to speak with one or more other subjects (e.g., other people) in the vicinity of the user. Additionally, the discussed techniques allow the user to effectively interact with other people without having to remove the wearable audio output device from its regular listening position, such that the user can simultaneously listen to audio being played on the device speakers while interacting with others.

Conventional ANR headphones generally require a user interface (UI) to change a level of the ANR. This UI may take many forms including a button press or a gesture control. Aspects of the present disclosure provide techniques for automatically lowering the ANR based on detecting a user's intent to speak with another subject (e.g., another person, automated voice system, etc.). Detecting the user's intent to speak may take into account a combination of detecting that the user is speaking (which may be captured by a beam-former on the headphone microphones and voice activity detection (VAD) that adapts to the overall noise floor of the environment) and checking for one or more other conditions to confirm that the user's detected speech is not related to a purpose other than to speak with another subject (e.g., speech related to a hands free profile (HFP) call, a voice command for a virtual personal assistant (VPA), the user singing, etc.).

In certain aspects, the discussed techniques provide a UI free solution to allow the user to multi-task, for example by interacting with a second party in the real-world while listening to a voice call or music on the headphone speakers.

<FIG> illustrates an example system <NUM> in which aspects of the present disclosure may be practiced.

As shown, system <NUM> includes a pair of headphones <NUM> worn by a user <NUM>. The headphones <NUM> are communicatively coupled to a portable user device <NUM>. According to the claimed invention, the headphones <NUM> include one or more microphones <NUM> to detect sound in the vicinity of the headphones <NUM>. The headphones <NUM> also include at least one acoustic transducer (also known as driver or speaker) for outputting sound. The included acoustic transducer(s) may be configured to transmit audio through air and/or through bone (e.g., via bone conduction, such as through the bones of the skull). The headphones <NUM> further include hardware and circuitry including processor(s)/processing system and memory configured to implement one or more sound management capabilities or other capabilities including, but not limited to, noise cancelling circuitry (not shown). The headphones <NUM> may additionally include noise masking circuitry (not shown), body movement detecting devices/sensors and circuitry (e.g., one or more accelerometers, one or more gyroscopes, one or more magnetometers, etc.), geolocation circuitry and other sound processing circuitry. The noise cancelling circuitry is configured to reduce unwanted ambient sounds external to the headphones <NUM> by using active noise cancelling (also known as active noise reduction). The sound masking circuitry is configured to reduce distractions by playing masking sounds via the speakers of the headphones <NUM>. The movement detecting circuitry is configured to use devices/sensors such as an accelerometer, gyroscope, magnetometer, or the like to detect whether the user wearing the headphones is moving (e.g., walking, running, in a moving mode of transport, etc.) or is at rest and/or the direction the user is looking or facing. The movement detecting circuitry may also be configured to detect a head position of the user for use in augmented reality (AR) applications where an AR sound is played back based on a direction of gaze of the user. The geolocation circuitry may be configured to detect a physical location of the user wearing the headphones. For example, the geolocation circuitry includes Global Positioning System (GPS) antenna and related circuitry to determine GPS coordinates of the user.

In an aspect, the headphones <NUM> include voice activity detection (VAD) circuitry capable of detecting the presence of speech signals (e.g. human speech signals) in a sound signal received by the microphones <NUM> of the headphones <NUM>. For instance, as shown in <FIG>, the microphones <NUM> of the headphones <NUM> receive ambient external sounds in the vicinity of the headphones <NUM>, including speech uttered by the user <NUM>. Thus, the sound signal received by the microphones <NUM> has the user's speech signal mixed in with other sounds in the vicinity of the headphones <NUM>. Using the VAD, the headphones <NUM> may detect and extract the speech signal from the received sound signal.

In an aspect, the headphones <NUM> include speaker identification circuitry capable of detecting an identity of a speaker to which a detected speech signal relates to. For example, the speaker identification circuitry may analyze one or more characteristics of a speech signal detected by the VAD circuitry and determine that the user <NUM> is the speaker. In an aspect, the speaker identification circuitry may use any of the existing speaker recognition methods and related systems to perform the speaker recognition.

In an aspect, the headphones <NUM> are wirelessly connected to the portable user device <NUM> using one or more wireless communication methods including but not limited to Bluetooth, Wi-Fi, Bluetooth Low Energy (BLE), other radio frequency (RF')-based techniques, or the like. In an aspect, the headphones <NUM> includes a transceiver that transmits and receives information via one or more antennae to exchange information with the user device <NUM>.

In an aspect, the headphones <NUM> may be connected to the portable user device <NUM> using a wired connection, with or without a corresponding wireless connection. As shown, the user device <NUM> may be connected to a network <NUM> (e.g., the Internet) and may access one or more services over the network. As shown, these services may include one or more cloud services <NUM>.

The portable user device <NUM> is representative of a variety of computing devices, such as mobile telephone (e.g., smart phone) or a computing tablet. In an aspect, the user device <NUM> may access a cloud server in the cloud <NUM> over the network <NUM> using a mobile web browser or a local software application or "app" executed on the user device <NUM>. In an aspect, the software application or "app" is a local application that is installed and runs locally on the user device <NUM>. In an aspect, a cloud server accessible on the cloud <NUM> includes one or more cloud applications that are run on the cloud server. The cloud application may be accessed and run by the user device <NUM>. For example, the cloud application may generate web pages that are rendered by the mobile web browser on the user device <NUM>. In an aspect, a mobile software application installed on the user device <NUM> and a cloud application installed on a cloud server, individually or in combination, may be used to implement the techniques for keyword recognition in accordance with aspects of the present disclosure.

It may be noted that although certain aspects of the present disclosure discuss automatic ANR control in the context of headphones <NUM> for exemplary purposes, any wearable audio output device with similar capabilities may be interchangeably used in these aspects. For instance, a wearable audio output device usable with techniques discussed herein may include over-the-ear headphones, audio eyeglasses or frames, in-ear buds, around-ear audio devices, open-ear audio devices (such as shoulder-worn or other body-worn audio devices) or the like.

<FIG> illustrates operations <NUM> performed by a wearable audio output device (e.g., headphones <NUM> as shown in <FIG>) worn by a user (e.g., user <NUM>) for controlling external noise attenuated by the wearable audio output device, in accordance with certain aspects of the present disclosure.

Operations <NUM> begin, at <NUM>, by detecting a speech signal from a user wearing the wearable audio output device, wherein the audio output device has active noise reduction turned on.

At <NUM>, it is determined, based at least on the detecting, that the user desires to speak to a subject in the vicinity of the user. According to the claimed invention, detecting that the user desires to speak to a subject in the vicinity of the user includes detecting at least one of the detected speech signal does not include a wake-up word (WUW) configured to trigger a voice personal assistant (VPA), the detected speech signal does not include voice commands for the VPA, or the user is streaming music to the audio output device and the speech signal does not indicate that the user is singing. Detecting that the user desires to speak to a subject in the vicinity of the user may additionally include detecting that the user is participating in a phone conversation using the audio output device and a voice stream of the user related to the phone conversation as received from the microphone of the audio output device is set to mute by the user.

At <NUM>, in response to determining that the user desires to speak to the subject in the vicinity of the user, a level of the active noise reduction is lowered to enable the user to hear sounds external to the audio output device.

In certain aspects, when at least one of the headphone microphones (e.g., microphones <NUM>) detect a sound in the vicinity of the user, the sound is analyzed to determine if the sound relates to or includes a speech signal generated as a result of the user speaking.

In an aspect, a sound signal detected by the headphone microphones is processed by a VAD module in the headphones, in an attempt to detect a speech signal. In an aspect, in order to avoid false triggers, the system confirms that a detected speech signal corresponds to the user speaking and not to other people speaking in the vicinity of the user. Thus, in an aspect, speaker identification is applied to a speech signal detected by the VAD module, in order to determine whether the speech signal corresponds to the user speaking. The speaker identification ensures that the ANR control algorithm is triggered only when the user is speaking and not when other subjects in the vicinity of the user are speaking.

In certain aspect, in order to avoid detecting speech signals from other subjects in the vicinity of the user, beamforming is applied to the microphone speakers and the microphone listening is focused in the general direction of the user's mouth. This lowers the possibility of the microphones receiving sounds from other directions and avoids unnecessary processing, thus saving power. Additionally, the microphone beamforming improves accuracy of detection of speech signals generated by the user speaking.

In an aspect, additionally or alternatively, one or more sensors in the headphones may be used to detect that the user is speaking. For example, an Inertial Measurement Unit (IMU) sensor in the headphones may be used to detect movements related to the user's mouth and the IMU data stream may be used to detect whether the user is speaking based on how the user's mouth is moving. In an aspect, the IMU sensor includes at least one of one or more accelerometers, one or more magnetometers, or one or more gyroscopes.

According to the claimed invention, detecting that the user desires to speak to another subject in the vicinity of the user includes checking for one or more conditions, and determining that the user desires to speak to another subject only when the one or more conditions are met.

One of the conditions includes determining that the detected speech signal does not relate to a wake-up word uttered by the user for triggering a Virtual Personal Assistant (VPA) module. In an aspect, the VPA module may be configured in the headphones or a user device (e.g., user device <NUM>) connected to the headphones. In an aspect, the headphones may include a language processing module for detecting whether the speech signal includes the wake-up word.

Another one of the conditions includes determining that the detected speech signal does not include a voice command for the VP A module or another voice interface. In an aspect, any speech from the user detected within a predetermined time from detecting the wake-up word uttered by the user is determined as a voice command for the VP A module.

A condition that forms part of the claimed invention only as an additional condition includes determining that the user is engaged in a voice call (e.g., a Bluetooth Hands Free Profile (HFP) call) and that the user's voice stream from the headphone microphones is muted for the voice call. In an example case, a user may be engaged in a conference call with one or more other parties, with the ANR turned on to avoid disturbances. It is typical for a user to temporarily mute the microphone stream so that other participants in the voice call are not disturbed by background noise in the user's vicinity. In an aspect, when it is determined that the user is engaged in a voice call and that the user's voice stream is muted for the voice call, the ANR control algorithm assumes that the user is okay to speak with a subject in the vicinity of the user. It may be noted that when the user mutes the headphone microphones during a voice call, the microphones may continue to detect sounds in the vicinity of the user including the user's voice stream without transmitting the detected voice stream, for example, to the user device for communicating to one or more parties engaged in the voice conversation with the user.

Another one of the conditions includes detecting that the user is listening to a music stream (e.g., over the Bluetooth A2DP or other music profile) over the headphone speakers and that the speech signal does not relate to the user singing or humming along. In an aspect, when it is detected the headphone speakers are playing a music stream and that the detected speech signal relates to the user singing or humming along, the ANR control algorithm determines that the user does not intend to speak with another subject in the vicinity of the user.

According to the claimed invention, the ANR control algorithm is configured to check for one or more of the above described conditions in order to determine whether the user desires to speak with another subject in the vicinity of the user. It may be noted that the above discussed conditions is not an exhaustive list of conditions, and that the ANR control algorithm may be configured to check for one or more additional conditions in an attempt to determine whether the user desires to speak with another subject.

According to the claimed invention, when the user is detected as speaking and when all the configured conditions are satisfied, the ANR control algorithm lowers the ANR so that the user is more acoustically aware of the user's surroundings. For example, the ANR is lowered only when it is determined that the detected speech signal does not relate to a wake-up word uttered by the user for triggering a VP A module, the detected speech signal does not include a voice command for the VPA module or another voice interface, it is determined that the user is engaged in a voice call and that the user's voice stream from the headphone microphones is muted for the voice call, and it is detected that the user is listening to a music stream (e.g., over the Bluetooth A2DP or other music profile) over the headphone speakers and that the speech signal does not relate to the user singing or humming along.

According to the claimed invention, the ANR is temporarily set to a predetermined low level (or temporarily turned off) to allow the user to hear external sounds more clearly and audibly. In an aspect, the temporary duration for lowering or turning off the ANR is defined by a pre-configured aware timer. In an aspect, the pre-configured aware timer is started when the ANR is lowered or turned off. In an aspect, the ANR is restored to its previous level or set to a pre-configured level (e.g., a higher level) when the aware timer expires.

In certain aspect, after the ANR has been lowered and when the aware timer is running, the ANR control algorithm continually monitors for speech uttered by the user. If further speech is detected from the user, the ANR checks for the configured conditions and resets the aware timer to the original configured value such that the aware state is extended by the aware timer duration. In an aspect, the aware timer is reset upon every instance of detecting speech from the user subject to all the configured conditions being satisfied.

In an aspect, the duration of the aware timer is selected as <NUM> minute as it is typical for the user to acknowledge the other party at least once every minute. However, this duration may be set to any value. In an aspect, the value of the aware timer may be configured by the user by using a user interface on the user device.

In certain aspects, in addition to lowering the ANR, a volume of audio/music playing on the headphone speakers may be optionally lowered or the audio/music may be paused or stopped from playing, in order to provide the user with better situational awareness.

The ANR control technique discussed in aspects of the present disclosure may be useful in several use cases.

In one example use case, not forming part of the claimed invention, the user may be participating in a conference call and may be streaming audio of the conference call to the headphones and may have the ANR turned on to avoid any disturbances while listening to the audio related to the conference call. The user may further have the microphone stream muted so that other participants in the conference call are not disturbed by background noise in the user's vicinity. When the user wishes to speak with another person in the vicinity of the user (e.g., a colleague wanting to speak with the user), the user may start speaking to the other person, and the ANR control algorithm in the headphones will automatically lower the ANR to aid the user to speak with the other person. In an aspect, even though the voice stream of the user is muted for the conference call, the microphones continue to listen to sounds in the vicinity of the user without transmitting the received sounds to the conferencing application for communication to other parties participating in the conference call. When the user starts speaking, the ANR control algorithm detects that the user is speaking (e.g., based on VAD and user identification) and further detects that the user's voice stream is muted. In response, the algorithm determines that the user desires to speak with another subject and automatically switches to an aware state by lowering the ANR (e.g., sets the ANR to a pre-configured level). This enables the user to speak to the other person while still monitoring the conference call, allowing the user to jump back into the call if needed (e.g., if a party in the conference call addresses the user). In an aspect, when the user unmutes the microphone stream to participate in the conference call, the aware state is automatically exited and the ANR is set to a predetermined high level or a previously set level (e.g., before the aware state was initialized).

In an aspect, in addition to lowering the ANR, the volume of the conferencing audio may be automatically lowered, or played only on one of the headphone speakers to aid the user's interaction with the other person. The ANR control algorithm may automatically restore the ANR level to a previous level, when the timer expires.

In certain aspects, it is common for user's participating in a voice call to temporarily mute the voice stream and then forget about it. The user may then start speaking to another party over the voice call not knowing that the user's voice stream is muted. The ANR control algorithm provides a clear audible feedback to the user to indicate that the user is speaking to a muted microphone. As noted above, when the user starts speaking with the user's voice stream set to mute, the headphones automatically enter an aware state and the ANR is automatically lowered. This change of ANR level from a higher noise reduction level to a lower level is typically a clear audible difference to the user and may act as a reminder that the user is speaking to a muted microphone.

In certain aspects, when the headphones are already in a lowered ANR state and whenever the user acknowledges another subject conversing with the user with any speech, the VAD triggers the ANR control logic described above, and if all conditions are met, the headphones continue to be in the aware state. In an aspect, this logic works under the assumption that most users would acknowledge a second party in a conversation vocally with sounds or words like "Hmmm", "okay", "that's right", "yes", "no", "interesting", etc., even if the user is not saying much in a two party conversation. Thus, when the headphones are already in the aware state, whenever the user utters one or more words that indicate the user is acknowledging the other party in a conversation, the aware timer is reset and the headphones continue to be in the aware state.

In another example not forming part of the claimed invention, certain aspects of the ANR control algorithm discussed in this disclosure may be used for controlling ANR for conversations initiated by subjects other than the user. For example, the headphones may enter the aware state and lower the ANR when another person starts a conversation with the user. One or more pre-configured words spoken by a non-user speaker may trigger the headphones to enter the aware state. These pre-configured words may include the user's name, one or more aliases, words and phrases generally used by people to address other people (e.g., Hello, Hi etc.,) or a combination thereof. Once the headphones enter the aware state and a conversation has started between the user and the other person, the logic described above may be used to extend the aware state of the headphone and to restore ANR levels.

<FIG> illustrates example operations <NUM> for an automatic ANR control algorithm, in certain aspects of the present disclosure.

Operations <NUM> begin, at <NUM>, by the algorithm detecting a speech signal. As described in the above paragraphs, one or more microphones of the ANR headphones detect external sounds in the vicinity of the headphones and the VAD module of the headphones may extract any speech signals included in the detected external sounds.

At <NUM>, the algorithm determines whether the detected speech signals correspond to the user speaking. As described in the above paragraphs, an existing user identification/recognition algorithm may be used in order make this determination. If it is determined that the user is not speaking, the algorithm is returned back to process block <NUM>, where the algorithm continues to monitor for speech signals.

When it is determined that the user is speaking at <NUM>, the algorithm checks for one or more configured conditions at <NUM> in order to determine whether the user desires to speak with another subject in the vicinity of the user. As described above, the configured conditions include at least one of determining that the detected speech signal does not relate to a wake-up word uttered by the user for triggering a VPA module, the detected speech signal does not include a voice command for the VPA module or another voice interface, or detecting that the user is listening to a music stream (e.g., over the Bluetooth A2DP or other music profile) over the headphone speakers and that the speech signal does not relate to the user singing or humming along. The configured conditions may additionally include determining that the user is engaged in a voice call and the user's voice stream from the headphone microphones is muted for the voice call.

At <NUM>, the algorithm determines whether all the configured conditions are satisfied. If all the configured conditions are determined as not satisfied, the algorithm is returned back to process block <NUM>. However, if all the configured conditions are determined as satisfied, the algorithm checks at <NUM> whether the ANR is set to a high level. If the ANR is determined as set to a high level, the headphones enter an aware state by setting the ANR to a pre-configured low level at <NUM>. At <NUM>, a timer (e.g., aware timer discussed above) is set to a predetermined value to set duration for the aware state.

In an aspect, if the ANR is determined as not set to high at <NUM>, the algorithm checks whether the aware timer is running at <NUM>. If the aware timer is not running, the algorithm is returned to process block <NUM>. In an aspect, the aware timer not running at <NUM> may indicate that the user has manually set the ANR to a low level which does not trigger the aware timer.

If the aware timer is determined as running at <NUM>, the algorithm extends the aware state by a predetermined duration at <NUM>. For example, the aware timer is extended by a predetermined value.

It may be noted that the processing related to the automatic ANR control as discussed in aspects of the present disclosure may be performed natively in the headphones, by the user device or a combination thereof.

It can be noted that, descriptions of aspects of the present disclosure are presented above for purposes of illustration, but aspects of the present disclosure are not intended to be limited to any of the disclosed aspects. Many modifications and variations will be apparent to those of ordinary skill in the art. The scope of the invention is defined solely by the appended claims.

In the preceding, reference is made to aspects presented in this disclosure. However, the scope of the present disclosure is not limited to specific described aspects. Aspects of the present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that can all generally be referred to herein as a "component," "circuit," "module" or "system. " Furthermore, aspects of the present disclosure can take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) can be utilized. The computer readable medium can be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples a computer readable storage medium include: an electrical connection having one or more wires, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the current context, a computer readable storage medium can be any tangible medium that can contain, or store a program.

Claim 1:
A method (<NUM>;<NUM>) of controlling a wearable audio output device (<NUM>) having active noise reduction (ANR) capabilities, the method comprising:
detecting (<NUM>;<NUM>) a speech signal from a user (<NUM>) wearing the wearable audio output device, wherein the ANR is set to an initial level;
in response to detecting the speech signal, determining (<NUM>;<NUM>-<NUM>) whether the user desires to speak to a subject in the vicinity of the user, by checking for one or more conditions confirming that the detected speech signal from the user is not related to a purpose other than to speak with a subject in the vicinity of the user;
in response to the determining, automatically setting (<NUM>;<NUM>) the ANR to allow the user to hear sounds external to the wearable audio output device more audibly relative to the initial level and starting a timer;
in response to detecting an additional speech signal from the user while the timer is running, extending or resetting the timer (<NUM>;<NUM>); and
in response to the timer expiring, automatically setting the ANR to the initial level,
the method characterized in that checking for one or more conditions confirming that the detected speech signal from the user is not related to a purpose other than to speak with a subject in the vicinity of the user includes:
- checking that the speech signal does not include a wake-up word (WUW) configured to trigger a voice personal assistant (VPA), and/or
- checking that the speech signal does not include voice commands for a voice personal assistant (VPA), and/or
- checking that the speech signal does not include singing or humming while music is being streamed to the wearable audio output device.