Patent Publication Number: US-2023134723-A1

Title: Networked Microphone Device Control

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 16/378,516, filed Apr. 8, 2029, titled “Networked Microphone Device Control,” and currently pending. U.S. application Ser. No. 16/378,516 is a continuation of U.S. application Ser. No. 15/438,725, filed Feb. 21, 2017, titled “Networked Microphone Device Control,” and issued as U.S. Pat. No. 10,264,030 on Apr. 16, 2019. The entire contents of U.S. application Ser. Nos. 16/378,516 and 15/438,725 are incorporated herein by reference. 
     The present application additionally incorporates by reference the entire contents of (i) U.S. Provisional App. 62/298,410, filed Feb. 22, 2016, titled “Default Playback Device(s),” and now expired; (ii) U.S. Provisional App. 62/298,418, filed Feb. 22, 2016, titled “Audio Response Playback,” and now expired; (iii) U.S. Provisional App. 62/298,433, filed Feb. 22, 2016, titled “Room-corrected Voice Detection,” and now expired; (iv) U.S. Provisional App. 62/298,439, filed Feb. 22, 2016, titled “Content Mixing,” and now expired; (v) U.S. Provisional App. 62/298,425, filed Feb. 22, 2016, titled “Music Service Selection,” and now expired; (vi) U.S. Provisional App. 62/298,350, filed Feb. 22, 2016, titled “Metadata exchange involving a networked playback system and a networked microphone system,” and now expired; (vii) U.S. Provisional App. 62/298,388, filed Feb. 22, 2016, titled “Handling of loss of pairing between networked devices,” and now expired; (viii) U.S. Provisional App. 62/298,393, filed Feb. 22, 2016, titled “Action based on User ID,” and now expired; and (ix) U.S. Provisional App. 62/312,350, filed Mar. 23, 2016, titled “Voice Control of a Media Playback System,” and now expired. 
    
    
     FIELD OF THE DISCLOSURE 
     The disclosure is related to consumer goods and, more particularly, to methods, systems, products, features, services, and other elements directed to media playback and aspects thereof. 
     BACKGROUND 
     Options for accessing and listening to digital audio in an out-loud setting were limited until in 2003, when Sonos, Inc. filed for one of its first patent applications, entitled “Method for Synchronizing Audio Playback between Multiple Networked Devices,” and began offering a media playback system for sale in 2005. The Sonos Wireless HiFi System enables people to experience music from many sources via one or more networked playback devices. Through a software control application installed on a smartphone, tablet, or computer, one can play what he or she wants in any room that has a networked playback device. Additionally, using the controller, for example, different songs can be streamed to each room with a playback device, rooms can be grouped together for synchronous playback, or the same song can be heard in all rooms synchronously. 
     Given the ever growing interest in digital media, there continues to be a need to develop consumer-accessible technologies to further enhance the listening experience. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, aspects, and advantages of the presently disclosed technology may be better understood with regard to the following description, appended claims, and accompanying drawings where: 
         FIG.  1    shows an example media playback system configuration in which certain embodiments may be practiced; 
         FIG.  2    shows a functional block diagram of an example playback device; 
         FIG.  3    shows a functional block diagram of an example control device; 
         FIG.  4    shows an example controller interface; 
         FIG.  5    shows an example plurality of network devices; 
         FIG.  6    shows a function block diagram of an example network microphone device; 
         FIG.  7    shows an example method according to some embodiments; and 
         FIG.  8    shows an example method according to some embodiments. 
     
    
    
     The drawings are for the purpose of illustrating example embodiments, but it is understood that the inventions are not limited to the arrangements and instrumentalities shown in the drawings. 
     DETAILED DESCRIPTION 
     I. Overview 
     In operation, the microphone(s) of a networked microphone device (“NMD”) are typically always on and listening for a specific “wake word” or “wake phrase.” In response to hearing the “wake” word or phrase, the NMD (i) records audio, e.g., the spoken words after the “wake” word/phrase, (ii) analyzes the recorded audio (or perhaps sends the recorded audio to a server for analysis), and (iii) takes action based on the recorded audio. In some instances, the action taken by the NMD may include providing information to a user, typically via a speaker of the NMD or a speaker associated with the NMD. Such information may include local weather reports, current traffic information, answers in response to questions (e.g., “How tall is the Empire State Building?”), and so on. In some instances, the action taken by the NMD may include controlling or changing the state of one or more networked devices. Such networked devices may include lights, garage doors, locks, networked media playback systems, televisions, thermostats, home alarm systems, and so on. 
     However, it may be desirable in some instances for the NMD to disable its microphone(s) from even listening for the “wake word” or “wake phrase.” For example, it may be undesirable for an NMD to have its microphone(s) enabled and listening for its “wake” word or phrase when a user is sleeping, engaging in sensitive conversations either in person or via telephone or computer, or perhaps simply enjoying private family time (e.g., dinner, movies, story time with children) because the NMD responds (typically via a speaker) with information and/or takes some other action in response to hearing its “wake” word or phrase, and it can be annoying or off-putting if the NMD interrupts their private time or activities with errant responses and/or actions. 
     In operation, disabling an NMD&#39;s microphone(s) has the effect of disconnecting the microphone from the NMD, thereby rendering the NMD unable to detect or process any audible signals/sounds in the room where the NMD is located while its microphone(s) is disabled. Disabling an NMD&#39;s microphone(s) could be accomplished via any of several different ways. For example, in some embodiments, disabling an NMD&#39;s microphone(s) may include switching off the power supplied to the microphone and/or microphone subsystem of the NMD. In some embodiments, disabling an NMD&#39;s microphone(s) may include switching off signal processing components configured to analyze and process sound detected by the microphone(s) of the NMD. In still further embodiments, disabling an NMD&#39;s microphone(s) may include disconnecting a signal path between the microphone(s) of the NMD and the signal processing components of the NMD configured to analyze and process sound detected by the microphone(s) of the NMD. The NMD&#39;s microphone(s) could also be disabled in any other way that prevents the NMD from listening to or otherwise detecting and/or analyzing audio sounds, speech, or other audible signals/sound, including but not limited to any “wake” word/phrase that would trigger the NMD to perform some function 
     While users may be able to unplug, power-off, or physically disable and re-enable the microphone(s) of an NMD via manual activation of a switch or button on the NMD, in some instances, taking such manual action can be cumbersome, inconvenient, or otherwise undesirable. It may be particularly cumbersome, inconvenient, and/or otherwise undesirable to disable multiple NMDs if a user had to manually actuate a physical button or switch on each NMD. 
     Because it is advantageous for an NMD to have the ability to disable and/or re-enable its microphone(s) without a user having to physically actuate a button/switch or power-off or unplug the NMD, in some embodiments, the NMD is configured to disable its microphone(s) in response to any one or more of: (i) determining that a reference device is in a particular state; (ii) receiving a voice command via the microphone(s) of the NMD; and (iii) receiving a command via a network interface of the NMD. And in some embodiments, the NMD is additionally or alternatively configured to enable its microphone(s) in response to any one or more of: (i) determining that a reference device is in a certain state; and (ii) receiving a command via a network interface of the NMD. Example reference devices include lights, garage doors, locks, networked media playback systems, televisions, thermostats, home alarm systems, other household sensors (e.g. motion sensors, audio sensors, light sensors, or other sensors). 
     Some embodiments described herein include, while the microphone of the NMD is enabled, (i) determining whether a first reference device is in a specific state, and (ii) in response to determining that the first reference device is in the specific state, disabling the microphone of the NMD. Some embodiments additionally or alternatively include, while the microphone of the NMD is disabled, (i) determining that the first reference device is no longer in the specific state and, (ii) in response to determining that the first reference device is no longer in the specific state, enabling the microphone of the NMD. 
     Some embodiments additionally or alternatively include, while the microphone of the NMD is disabled, (i) determining that a second reference device is in a particular state, and (ii) in response to determining that the second reference device is in the particular state, enabling the microphone of the networked microphone device. 
     Some embodiments additionally or alternatively include, while the microphone of the NMD is enabled, (i) receiving a command to disable the microphone of the NMD via one of (i-a) the microphone of the NMD or (i-b) a network interface of the NMD, and (ii) in response to receiving the command to disable the microphone of the NMD via one of the microphone of the NMD or the network interface of the NMD, disabling the microphone of the NMD. 
     While some examples described herein may refer to functions performed by given actors such as “users” and/or other entities, it should be understood that this is for purposes of explanation only. The claims should not be interpreted to require action by any such example actor unless explicitly required by the language of the claims themselves. 
     It will be understood by one of ordinary skill in the art that this disclosure includes numerous other embodiments. 
     II. Example Operating Environment 
       FIG.  1    shows an example configuration of a media playback system  100  in which one or more embodiments disclosed herein may be practiced or implemented. The media playback system  100  as shown is associated with an example home environment having several rooms and spaces, such as for example, a master bedroom, an office, a dining room, and a living room. As shown in the example of  FIG.  1   , the media playback system  100  includes playback devices  102 - 124 , control devices  126  and  128 , and a wired or wireless network router  130 . 
     Further discussions relating to the different components of the example media playback system  100  and how the different components may interact to provide a user with a media experience may be found in the following sections. While discussions herein may generally refer to the example media playback system  100 , technologies described herein are not limited to applications within, among other things, the home environment as shown in  FIG.  1   . For instance, the technologies described herein may be useful in environments where multi-zone audio may be desired, such as, for example, a commercial setting like a restaurant, mall or airport, a vehicle like a sports utility vehicle (SUV), bus or car, a ship or boat, an airplane, and so on. 
     a. Example Playback Devices 
       FIG.  2    shows a functional block diagram of an example playback device  200  that may be configured to be one or more of the playback devices  102 - 124  of the media playback system  100  of  FIG.  1   . The playback device  200  may include one or more processors  202 , software components  204 , memory  206 , audio processing components  208 , audio amplifier(s)  210 , speaker(s)  212 , a network interface  214  including wireless interface(s)  216  and wired interface(s)  218 , and microphone(s)  220 . In one case, the playback device  200  may not include the speaker(s)  212 , but rather a speaker interface for connecting the playback device  200  to external speakers. In another case, the playback device  200  may include neither the speaker(s)  212  nor the audio amplifier(s)  210 , but rather an audio interface for connecting the playback device  200  to an external audio amplifier or audio-visual receiver. 
     In one example, the one or more processors  202  may be one or more clock-driven computing components configured to process input data according to instructions stored in the memory  206 . The memory  206  may be a tangible computer-readable medium configured to store instructions executable by the one or more processors  202 . For instance, the memory  206  may be data storage that can be loaded with one or more of the software components  204  executable by the one or more processors  202  to achieve certain functions. In one example, the functions may involve the playback device  200  retrieving audio data from an audio source or another playback device. In another example, the functions may involve the playback device  200  sending audio data to another device or playback device on a network. In yet another example, the functions may involve pairing of the playback device  200  with one or more playback devices to create a multi-channel audio environment. 
     Certain functions may involve the playback device  200  synchronizing playback of audio content with one or more other playback devices. During synchronous playback, a listener will preferably not be able to perceive time-delay differences between playback of the audio content by the playback device  200  and the one or more other playback devices. U.S. Pat. No. 8,234,395 entitled, “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is hereby incorporated by reference, provides in more detail some examples for audio playback synchronization among playback devices. 
     The memory  206  may further be configured to store data associated with the playback device  200 , such as one or more zones and/or zone groups the playback device  200  is a part of, audio sources accessible by the playback device  200 , or a playback queue that the playback device  200  (or some other playback device) may be associated with. The data may be stored as one or more state variables that are periodically updated and used to describe the state of the playback device  200 . The memory  206  may also include the data associated with the state of the other devices of the media system, and shared from time to time among the devices so that one or more of the devices have the most recent data associated with the system. Other embodiments are also possible. 
     The audio processing components  208  may include one or more digital-to-analog converters (DAC), an audio preprocessing component, an audio enhancement component or a digital signal processor (DSP), and so on. In one embodiment, one or more of the audio processing components  208  may be a subcomponent of the one or more processors  202 . In one example, audio content may be processed and/or intentionally altered by the audio processing components  208  to produce audio signals. The produced audio signals may then be provided to the audio amplifier(s)  210  for amplification and playback through speaker(s)  212 . Particularly, the audio amplifier(s)  210  may include devices configured to amplify audio signals to a level for driving one or more of the speakers  212 . The speaker(s)  212  may include an individual transducer (e.g., a “driver”) or a complete speaker system involving an enclosure with one or more drivers. A particular driver of the speaker(s)  212  may include, for example, a subwoofer (e.g., for low frequencies), a mid-range driver (e.g., for middle frequencies), and/or a tweeter (e.g., for high frequencies). In some cases, each transducer in the one or more speakers  212  may be driven by an individual corresponding audio amplifier of the audio amplifier(s)  210 . In addition to producing analog signals for playback by the playback device  200 , the audio processing components  208  may be configured to process audio content to be sent to one or more other playback devices for playback. 
     Audio content to be processed and/or played back by the playback device  200  may be received from an external source, such as via an audio line-in input connection (e.g., an auto-detecting 3.5 mm audio line-in connection) or the network interface  214 . 
     The network interface  214  may be configured to facilitate a data flow between the playback device  200  and one or more other devices on a data network. As such, the playback device  200  may be configured to receive audio content over the data network from one or more other playback devices in communication with the playback device  200 , network devices within a local area network, or audio content sources over a wide area network such as the Internet. The playback device  200  may transmit metadata to and/or receive metadata from other devices on the network, including but not limited to components of the networked microphone system disclosed and described herein. In one example, the audio content and other signals (e.g., metadata and other signals) transmitted and received by the playback device  200  may be transmitted in the form of digital packet data containing an Internet Protocol (IP)-based source address and IP-based destination addresses. In such a case, the network interface  214  may be configured to parse the digital packet data such that the data destined for the playback device  200  is properly received and processed by the playback device  200 . 
     As shown, the network interface  214  may include wireless interface(s)  216  and wired interface(s)  218 . The wireless interface(s)  216  may provide network interface functions for the playback device  200  to wirelessly communicate with other devices (e.g., other playback device(s), speaker(s), receiver(s), network device(s), control device(s) within a data network the playback device  200  is associated with) in accordance with a communication protocol (e.g., any wireless standard including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G mobile communication standard, and so on). The wired interface(s)  218  may provide network interface functions for the playback device  200  to communicate over a wired connection with other devices in accordance with a communication protocol (e.g., IEEE 802.3). While the network interface  214  shown in  FIG.  2    includes both wireless interface(s)  216  and wired interface(s)  218 , the network interface  214  may in some embodiments include only wireless interface(s) or only wired interface(s). 
     The microphone(s)  220  may be arranged to detect sound in the environment of the playback device  200 . For instance, the microphone(s) may be mounted on an exterior wall of a housing of the playback device. The microphone(s) may be any type of microphone now known or later developed such as a condenser microphone, electret condenser microphone, or a dynamic microphone. The microphone(s) may be sensitive to a portion of the frequency range of the speaker(s)  220 . One or more of the speaker(s)  220  may operate in reverse as the microphone(s)  220 . In some aspects, the playback device  200  might not have microphone(s)  220 . 
     In one example, the playback device  200  and one other playback device may be paired to play two separate audio components of audio content. For instance, playback device  200  may be configured to play a left channel audio component, while the other playback device may be configured to play a right channel audio component, thereby producing or enhancing a stereo effect of the audio content. The paired playback devices (also referred to as “bonded playback devices”) may further play audio content in synchrony with other playback devices. 
     In another example, the playback device  200  may be sonically consolidated with one or more other playback devices to form a single, consolidated playback device. A consolidated playback device may be configured to process and reproduce sound differently than an unconsolidated playback device or playback devices that are paired, because a consolidated playback device may have additional speaker drivers through which audio content may be rendered. For instance, if the playback device  200  is a playback device designed to render low frequency range audio content (i.e. a subwoofer), the playback device  200  may be consolidated with a playback device designed to render full frequency range audio content. In such a case, the full frequency range playback device, when consolidated with the low frequency playback device  200 , may be configured to render only the mid and high frequency components of audio content, while the low frequency range playback device  200  renders the low frequency component of the audio content. The consolidated playback device may further be paired with a single playback device or yet another consolidated playback device. 
     By way of illustration, Sonos, Inc. presently offers (or has offered) for sale certain playback devices including a “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any other past, present, and/or future playback devices may additionally or alternatively be used to implement the playback devices of example embodiments disclosed herein. Additionally, it is understood that a playback device is not limited to the example illustrated in  FIG.  2    or to the Sonos product offerings. For example, a playback device may include a wired or wireless headphone. In another example, a playback device may include or interact with a docking station for personal mobile media playback devices. In yet another example, a playback device may be integral to another device or component such as a television, a lighting fixture, or some other device for indoor or outdoor use. 
     b. Example Playback Zone Configurations 
     Referring back to the media playback system  100  of  FIG.  1   , the environment may have one or more playback zones, each with one or more playback devices. The media playback system  100  may be established with one or more playback zones, after which one or more zones may be added, or removed to arrive at the example configuration shown in  FIG.  1   . Each zone may be given a name according to a different room or space such as an office, bathroom, master bedroom, bedroom, kitchen, dining room, living room, and/or balcony. In one case, a single playback zone may include multiple rooms or spaces. In another case, a single room or space may include multiple playback zones. 
     As shown in  FIG.  1   , the balcony, dining room, kitchen, bathroom, office, and bedroom zones each have one playback device, while the living room and master bedroom zones each have multiple playback devices. In the living room zone, playback devices  104 ,  106 ,  108 , and  110  may be configured to play audio content in synchrony as individual playback devices, as one or more bonded playback devices, as one or more consolidated playback devices, or any combination thereof. Similarly, in the case of the master bedroom, playback devices  122  and  124  may be configured to play audio content in synchrony as individual playback devices, as a bonded playback device, or as a consolidated playback device. 
     In one example, one or more playback zones in the environment of  FIG.  1    may each be playing different audio content. For instance, the user may be grilling in the balcony zone and listening to hip hop music being played by the playback device  102  while another user may be preparing food in the kitchen zone and listening to classical music being played by the playback device  114 . In another example, a playback zone may play the same audio content in synchrony with another playback zone. For instance, the user may be in the office zone where the playback device  118  is playing the same rock music that is being playing by playback device  102  in the balcony zone. In such a case, playback devices  102  and  118  may be playing the rock music in synchrony such that the user may seamlessly (or at least substantially seamlessly) enjoy the audio content that is being played out-loud while moving between different playback zones. Synchronization among playback zones may be achieved in a manner similar to that of synchronization among playback devices, as described in previously referenced U.S. Pat. No. 8,234,395. 
     As suggested above, the zone configurations of the media playback system  100  may be dynamically modified, and in some embodiments, the media playback system  100  supports numerous configurations. For instance, if a user physically moves one or more playback devices to or from a zone, the media playback system  100  may be reconfigured to accommodate the change(s). For instance, if the user physically moves the playback device  102  from the balcony zone to the office zone, the office zone may now include both the playback device  118  and the playback device  102 . The playback device  102  may be paired or grouped with the office zone and/or renamed if so desired via a control device such as the control devices  126  and  128 . On the other hand, if the one or more playback devices are moved to a particular area in the home environment that is not already a playback zone, a new playback zone may be created for the particular area. 
     Further, different playback zones of the media playback system  100  may be dynamically combined into zone groups or split up into individual playback zones. For instance, the dining room zone and the kitchen zone  114  may be combined into a zone group for a dinner party such that playback devices  112  and  114  may render (e.g., play back) audio content in synchrony. On the other hand, the living room zone may be split into a television zone including playback device  104 , and a listening zone including playback devices  106 ,  108 , and  110 , if the user wishes to listen to music in the living room space while another user wishes to watch television. 
     c. Example Control Devices 
       FIG.  3    shows a functional block diagram of an example control device  300  that may be configured to be one or both of the control devices  126  and  128  of the media playback system  100 . As shown, the control device  300  may include one or more processors  302 , memory  304 , a network interface  306 , a user interface  308 , microphone(s)  310 , and software components  312 . In one example, the control device  300  may be a dedicated controller for the media playback system  100 . In another example, the control device  300  may be a network device on which media playback system controller application software may be installed, such as for example, an iPhone™, iPad™ or any other smart phone, tablet or network device (e.g., a networked computer such as a PC or Mac™). 
     The one or more processors  302  may be configured to perform functions relevant to facilitating user access, control, and configuration of the media playback system  100 . The memory  304  may be data storage that can be loaded with one or more of the software components executable by the one or more processors  302  to perform those functions. The memory  304  may also be configured to store the media playback system controller application software and other data associated with the media playback system  100  and the user. 
     In one example, the network interface  306  may be based on an industry standard (e.g., infrared, radio, wired standards including IEEE 802.3, wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 3G, 4G, or 5G mobile communication standards, and so on). The network interface  306  may provide a means for the control device  300  to communicate with other devices in the media playback system  100 . In one example, data and information (e.g., such as a state variable) may be communicated between control device  300  and other devices via the network interface  306 . For instance, playback zone and zone group configurations in the media playback system  100  may be received by the control device  300  from a playback device or another network device, or transmitted by the control device  300  to another playback device or network device via the network interface  306 . In some cases, the other network device may be another control device. 
     Playback device control commands such as volume control and audio playback control may also be communicated from the control device  300  to a playback device via the network interface  306 . As suggested above, changes to configurations of the media playback system  100  may also be performed by a user using the control device  300 . The configuration changes may include adding/removing one or more playback devices to/from a zone, adding/removing one or more zones to/from a zone group, forming a bonded or consolidated player, separating one or more playback devices from a bonded or consolidated player, among others. Accordingly, the control device  300  may sometimes be referred to as a controller, whether the control device  300  is a dedicated controller or a network device on which media playback system controller application software is installed. 
     Control device  300  may include microphone(s)  310 . Microphone(s)  310  may be arranged to detect sound in the environment of the control device  300 . Microphone(s)  310  may be any type of microphone now known or later developed such as a condenser microphone, electret condenser microphone, or a dynamic microphone. The microphone(s) may be sensitive to a portion of a frequency range. Two or more microphones  310  may be arranged to capture location information of an audio source (e.g., voice, audible sound) and/or to assist in filtering background noise. 
     The user interface  308  of the control device  300  may be configured to facilitate user access and control of the media playback system  100 , by providing a controller interface such as the example controller interface  400  shown in  FIG.  4   . The controller interface  400  includes a playback control region  410 , a playback zone region  420 , a playback status region  430 , a playback queue region  440 , and an audio content sources region  450 . The user interface  400  as shown is just one example of a user interface that may be provided on a network device such as the control device  300  of  FIG.  3    (and/or the control devices  126  and  128  of  FIG.  1   ) and accessed by users to control a media playback system such as the media playback system  100 . Other user interfaces of varying formats, styles, and interactive sequences may alternatively be implemented on one or more network devices to provide comparable control access to a media playback system. 
     The playback control region  410  may include selectable (e.g., by way of touch or by using a cursor) icons to cause playback devices in a selected playback zone or zone group to play or pause, fast forward, rewind, skip to next, skip to previous, enter/exit shuffle mode, enter/exit repeat mode, enter/exit cross fade mode. The playback control region  410  may also include selectable icons to modify equalization settings, and playback volume, among other possibilities. 
     The playback zone region  420  may include representations of playback zones within the media playback system  100 . In some embodiments, the graphical representations of playback zones may be selectable to bring up additional selectable icons to manage or configure the playback zones in the media playback system, such as a creation of bonded zones, creation of zone groups, separation of zone groups, and renaming of zone groups, among other possibilities. 
     For example, as shown, a “group” icon may be provided within each of the graphical representations of playback zones. The “group” icon provided within a graphical representation of a particular zone may be selectable to bring up options to select one or more other zones in the media playback system to be grouped with the particular zone. Once grouped, playback devices in the zones that have been grouped with the particular zone will be configured to play audio content in synchrony with the playback device(s) in the particular zone. Analogously, a “group” icon may be provided within a graphical representation of a zone group. In this case, the “group” icon may be selectable to bring up options to deselect one or more zones in the zone group to be removed from the zone group. Other interactions and implementations for grouping and ungrouping zones via a user interface such as the user interface  400  are also possible. The representations of playback zones in the playback zone region  420  may be dynamically updated as playback zone or zone group configurations are modified. 
     The playback status region  430  may include graphical representations of audio content that is presently being played, previously played, or scheduled to play next in the selected playback zone or zone group. The selected playback zone or zone group may be visually distinguished on the user interface, such as within the playback zone region  420  and/or the playback status region  430 . The graphical representations may include track title, artist name, album name, album year, track length, and other relevant information that may be useful for the user to know when controlling the media playback system via the user interface  400 . 
     The playback queue region  440  may include graphical representations of audio content in a playback queue associated with the selected playback zone or zone group. In some embodiments, each playback zone or zone group may be associated with a playback queue containing information corresponding to zero or more audio items for playback by the playback zone or zone group. For instance, each audio item in the playback queue may comprise a uniform resource identifier (URI), a uniform resource locator (URL) or some other identifier that may be used by a playback device in the playback zone or zone group to find and/or retrieve the audio item from a local audio content source or a networked audio content source, possibly for playback by the playback device. 
     In one example, a playlist may be added to a playback queue, in which case information corresponding to each audio item in the playlist may be added to the playback queue. In another example, audio items in a playback queue may be saved as a playlist. In a further example, a playback queue may be empty, or populated but “not in use” when the playback zone or zone group is playing continuously streaming audio content, such as Internet radio that may continue to play until otherwise stopped, rather than discrete audio items that have playback durations. In an alternative embodiment, a playback queue can include Internet radio and/or other streaming audio content items and be “in use” when the playback zone or zone group is playing those items. Other examples are also possible. 
     When playback zones or zone groups are “grouped” or “ungrouped,” playback queues associated with the affected playback zones or zone groups may be cleared or re-associated. For example, if a first playback zone including a first playback queue is grouped with a second playback zone including a second playback queue, the established zone group may have an associated playback queue that is initially empty, that contains audio items from the first playback queue (such as if the second playback zone was added to the first playback zone), that contains audio items from the second playback queue (such as if the first playback zone was added to the second playback zone), or a combination of audio items from both the first and second playback queues. Subsequently, if the established zone group is ungrouped, the resulting first playback zone may be re-associated with the previous first playback queue, or be associated with a new playback queue that is empty or contains audio items from the playback queue associated with the established zone group before the established zone group was ungrouped. Similarly, the resulting second playback zone may be re-associated with the previous second playback queue, or be associated with a new playback queue that is empty, or contains audio items from the playback queue associated with the established zone group before the established zone group was ungrouped. Other examples are also possible. 
     Referring back to the user interface  400  of  FIG.  4   , the graphical representations of audio content in the playback queue region  440  may include track titles, artist names, track lengths, and other relevant information associated with the audio content in the playback queue. In one example, graphical representations of audio content may be selectable to bring up additional selectable icons to manage and/or manipulate the playback queue and/or audio content represented in the playback queue. For instance, a represented audio content may be removed from the playback queue, moved to a different position within the playback queue, or selected to be played immediately, or after any currently playing audio content, among other possibilities. A playback queue associated with a playback zone or zone group may be stored in a memory on one or more playback devices in the playback zone or zone group, on a playback device that is not in the playback zone or zone group, and/or some other designated device. 
     The audio content sources region  450  may include graphical representations of selectable audio content sources from which audio content may be retrieved and played by the selected playback zone or zone group. Discussions pertaining to audio content sources may be found in the following section. 
     d. Example Audio Content Sources 
     As indicated previously, one or more playback devices in a zone or zone group may be configured to retrieve for playback audio content (e.g. according to a corresponding URI or URL for the audio content) from a variety of available audio content sources. In one example, audio content may be retrieved by a playback device directly from a corresponding audio content source (e.g., a line-in connection). In another example, audio content may be provided to a playback device over a network via one or more other playback devices or network devices. 
     Example audio content sources may include a memory of one or more playback devices in a media playback system such as the media playback system  100  of  FIG.  1   , local music libraries on one or more network devices (such as a control device, a network-enabled personal computer, or a networked-attached storage (NAS), for example), streaming audio services providing audio content via the Internet (e.g., the cloud), or audio sources connected to the media playback system via a line-in input connection on a playback device or network devise, among other possibilities. 
     In some embodiments, audio content sources may be regularly added or removed from a media playback system such as the media playback system  100  of  FIG.  1   . In one example, an indexing of audio items may be performed whenever one or more audio content sources are added, removed or updated. Indexing of audio items may involve scanning for identifiable audio items in all folders/directory shared over a network accessible by playback devices in the media playback system, and generating or updating an audio content database containing metadata (e.g., title, artist, album, track length, among others) and other associated information, such as a URI or URL for each identifiable audio item found. Other examples for managing and maintaining audio content sources may also be possible. 
     The above discussions relating to playback devices, controller devices, playback zone configurations, and media content sources provide only some examples of operating environments within which functions and methods described below may be implemented. Other operating environments and configurations of media playback systems, playback devices, and network devices not explicitly described herein may also be applicable and suitable for implementation of the functions and methods. 
     e. Example Plurality of Networked Devices 
       FIG.  5    shows an example plurality of devices  500  that may be configured to provide an audio playback experience based on voice control. One having ordinary skill in the art will appreciate that the devices shown in  FIG.  5    are for illustrative purposes only, and variations including different and/or additional (or fewer) devices may be possible. As shown, the plurality of devices  500  includes computing devices  504 ,  506 , and  508 ; network microphone devices (NMDs)  512 ,  514 , and  516 ; playback devices (PBDs)  532 ,  534 ,  536 , and  538 ; and a controller device (CR)  522 . 
     Each of the plurality of devices  500  may be network-capable devices that can establish communication with one or more other devices in the plurality of devices according to one or more network protocols, such as NFC, Bluetooth™, Ethernet, and IEEE 802.11, among other examples, over one or more types of networks, such as wide area networks (WAN), local area networks (LAN), and personal area networks (PAN), among other possibilities. 
     As shown, the computing devices  504 ,  506 , and  508  may be part of a cloud network  502 . The cloud network  502  may include additional computing devices. In one example, the computing devices  504 ,  506 , and  508  may be different servers. In another example, two or more of the computing devices  504 ,  506 , and  508  may be modules of a single server. Analogously, each of the computing device  504 ,  506 , and  508  may include one or more modules or servers. For ease of illustration purposes herein, each of the computing devices  504 ,  506 , and  508  may be configured to perform particular functions within the cloud network  502 . For instance, computing device  508  may be a source of audio content for a streaming music service. 
     As shown, the computing device  504  may be configured to interface with NMDs  512 ,  514 , and  516  via communication path  542 . NMDs  512 ,  514 , and  516  may be components of one or more “Smart Home” systems. In one case, NMDs  512 ,  514 , and  516  may be physically distributed throughout a household, similar to the distribution of devices shown in  FIG.  1   . In another case, two or more of the NMDs  512 ,  514 , and  516  may be physically positioned within relative close proximity of one another. Communication path  542  may comprise one or more types of networks, such as a WAN including the Internet, LAN, and/or PAN, among other possibilities. 
     In one example, one or more of the NMDs  512 ,  514 , and  516  may be devices configured primarily for audio detection. In another example, one or more of the NMDs  512 ,  514 , and  516  may be components of devices having various primary utilities. For instance, as discussed above in connection to  FIGS.  2  and  3   , one or more of NMDs  512 ,  514 , and  516  may be (or at least may include or be a component of) the microphone(s)  220  of playback device  200  or the microphone(s)  310  of network device  300 . Further, in some cases, one or more of NMDs  512 ,  514 , and  516  may be (or at least may include or be a component of) the playback device  200  or network device  300 . In an example, one or more of NMDs  512 ,  514 , and/or  516  may include multiple microphones arranged in a microphone array. In some embodiments, one or more of NMDs  512 ,  514 , and/or  516  may be a microphone on a mobile computing device (e.g., a smartphone, tablet, or other computing device). 
     As shown, the computing device  506  may be configured to interface with CR  522  and PBDs  532 ,  534 ,  536 , and  538  via communication path  544 . In one example, CR  522  may be a network device such as the network device  200  of  FIG.  2   . Accordingly, CR  522  may be configured to provide the controller interface  400  of  FIG.  4   . Similarly, PBDs  532 ,  534 ,  536 , and  538  may be playback devices such as the playback device  300  of  FIG.  3   . As such, PBDs  532 ,  534 ,  536 , and  538  may be physically distributed throughout a household as shown in  FIG.  1   . For illustration purposes, PBDs  536  and  538  may be part of a bonded zone  530 , while PBDs  532  and  534  may be part of their own respective zones. As described above, the PBDs  532 ,  534 ,  536 , and  538  may be dynamically bonded, grouped, unbonded, and ungrouped. Communication path  544  may comprise one or more types of networks, such as a WAN including the Internet, LAN, and/or PAN, among other possibilities. 
     In one example, as with NMDs  512 ,  514 , and  516 , CR  522  and PBDs  532 ,  534 ,  536 , and  538  may also be components of one or more “Smart Home” systems. In one case, PBDs  532 ,  534 ,  536 , and  538  may be distributed throughout the same household as the NMDs  512 ,  514 , and  516 . Further, as suggested above, one or more of PBDs  532 ,  534 ,  536 , and  538  may be one or more of NMDs  512 ,  514 , and  516 . 
     The NMDs  512 ,  514 , and  516  may be part of a local area network, and the communication path  542  may include an access point that links the local area network of the NMDs  512 ,  514 , and  516  to the computing device  504  over a WAN (communication path not shown). Likewise, each of the NMDs  512 ,  514 , and  516  may communicate with each other via such an access point. 
     Similarly, CR  522  and PBDs  532 ,  534 ,  536 , and  538  may be part of a local area network and/or a local playback network as discussed in previous sections, and the communication path  544  may include an access point that links the local area network and/or local playback network of CR  522  and PBDs  532 ,  534 ,  536 , and  538  to the computing device  506  over a WAN. As such, each of the CR  522  and PBDs  532 ,  534 ,  536 , and  538  may also communicate with each over such an access point. 
     In one example, communication paths  542  and  544  may comprise the same access point. In an example, each of the NMDs  512 ,  514 , and  516 , CR  522 , and PBDs  532 ,  534 ,  536 , and  538  may access the cloud network  502  via the same access point for a household. 
     As shown in  FIG.  5   , each of the NMDs  512 ,  514 , and  516 , CR  522 , and PBDs  532 ,  534 ,  536 , and  538  may also directly communicate with one or more of the other devices via communication means  546 . Communication means  546  as described herein may involve one or more forms of communication between the devices, according to one or more network protocols, over one or more types of networks, and/or may involve communication via one or more other network devices. For instance, communication means  546  may include one or more of for example, Bluetooth™ (IEEE 802.15), NFC, Wireless direct, and/or Proprietary wireless, among other possibilities. 
     In one example, CR  522  may communicate with NMD  512  over Bluetooth™, and communicate with PBD  534  over another local area network. In another example, NMD  514  may communicate with CR  522  over another local area network, and communicate with PBD  536  over Bluetooth™. In a further example, each of the PBDs  532 ,  534 ,  536 , and  538  may communicate with each other according to a spanning tree protocol over a local playback network, while each communicating with CR  522  over a local area network, different from the local playback network. Other examples are also possible. 
     In some cases, communication means between the NMDs  512 ,  514 , and  516 , CR  522 , and PBDs  532 ,  534 ,  536 , and  538  may change depending on types of communication between the devices, network conditions, and/or latency demands. For instance, communication means  546  may be used when NMD  516  is first introduced to the household with the PBDs  532 ,  534 ,  536 , and  538 . In one case, the NMD  516  may transmit identification information corresponding to the NMD  516  to PBD  538  via NFC, and PBD  538  may in response, transmit local area network information to NMD  516  via NFC (or some other form of communication). However, once NMD  516  has been configured within the household, communication means between NMD  516  and PBD  538  may change. For instance, NMD  516  may subsequently communicate with PBD  538  via communication path  542 , the cloud network  502 , and communication path  544 . In another example, the NMDs and PBDs may never communicate via local communications means  546 . In a further example, the NMDs and PBDs may communicate primarily via local communications means  546 . Other examples are also possible. 
     In an illustrative example, NMDs  512 ,  514 , and  516  may be configured to receive voice inputs to control PBDs  532 ,  534 ,  536 , and  538 . The available control commands may include any media playback system controls previously discussed, such as playback volume control, playback transport controls, music source selection, and grouping, among other possibilities. In one instance, NMD  512  may receive a voice input to control one or more of the PBDs  532 ,  534 ,  536 , and  538 . In response to receiving the voice input, NMD  512  may transmit via communication path  542 , the voice input to computing device  504  for processing. In one example, the computing device  504  may convert the voice input to an equivalent text command, and parse the text command to identify a command. Computing device  504  may then subsequently transmit the text command to the computing device  506 , and computing device  506  in turn may then control one or more of PBDs  532 - 538  to execute the command. In another example, the computing device  504  may convert the voice input to an equivalent text command, and then subsequently transmit the text command to the computing device  506 . The computing device  506  may then parse the text command to identify one or more playback commands, and then computing device  506  may additionally control one or more of PBDs  532 - 538  to execute the command. 
     For instance, if the text command is “Play ‘Track 1’ by ‘Artist 1’ from ‘Streaming Service 1’ in ‘Zone 1’,” The computing device  506  may identify (i) a URL for “Track 1” by “Artist 1” available from “Streaming Service 1,” and (ii) at least one playback device in “Zone 1.” In this example, the URL for “Track 1” by “Artist 1” from “Streaming Service 1” may be a URL pointing to computing device  508 , and “Zone 1” may be the bonded zone  530 . As such, upon identifying the URL and one or both of PBDs  536  and  538 , the computing device  506  may transmit via communication path  544  to one or both of PBDs  536  and  538 , the identified URL for playback. One or both of PBDs  536  and  538  may responsively retrieve audio content from the computing device  508  according to the received URL, and begin playing “Track 1” by “Artist 1” from “Streaming Service 1.” 
     One having ordinary skill in the art will appreciate that the above is just one illustrative example, and that other implementations are also possible. In one case, operations performed by one or more of the plurality of devices  500 , as described above, may be performed by one or more other devices in the plurality of device  500 . For instance, the conversion from voice input to the text command may be alternatively, partially, or wholly performed by another device or devices, such as CR  522 , NMD  512 , computing device  506 , PBD  536 , and/or PBD  538 . Analogously, the identification of the URL may be alternatively, partially, or wholly performed by another device or devices, such as NMD  512 , computing device  504 , PBD  536 , and/or PBD  538 . 
     f. Example Network Microphone Device 
       FIG.  6    shows a function block diagram of an example network microphone device  600  that may be configured to be one or more of NMDs  512 ,  514 , and  516  of  FIG.  5   . As shown, the network microphone device  600  includes one or more processors  602 , memory  604 , a microphone array  606  (e.g., one or more microphones), a network interface  608 , a user interface  610 , software components  612 , and speaker(s)  614 . One having ordinary skill in the art will appreciate that other network microphone device configurations and arrangements are also possible. For instance, network microphone devices may alternatively exclude the speaker(s)  614  or have a single microphone instead of microphone array  606 . 
     The one or more processors  602  may include one or more processors and/or controllers, which may take the form of a general or special-purpose processor or controller. For instance, the one or more processors  602  may include microprocessors, microcontrollers, application-specific integrated circuits, digital signal processors, and the like. The memory  604  may be data storage that can be loaded with one or more of the software components executable by the one or more processors  602  to perform those functions. Accordingly, memory  604  may comprise one or more non-transitory computer-readable storage mediums, examples of which may include volatile storage mediums such as random access memory, registers, cache, etc. and non-volatile storage mediums such as read-only memory, a hard-disk drive, a solid-state drive, flash memory, and/or an optical-storage device, among other possibilities. 
     The microphone array  606  may be a plurality of microphones arranged to detect sound in the environment of the network microphone device  600 . Microphone array  606  may include any type of microphone now known or later developed such as a condenser microphone, electret condenser microphone, or a dynamic microphone, among other possibilities. In one example, the microphone array may be arranged to detect audio from one or more directions relative to the network microphone device. The microphone array  606  may be sensitive to a portion of a frequency range. In one example, a first subset of the microphone array  606  may be sensitive to a first frequency range, while a second subset of the microphone array may be sensitive to a second frequency range. The microphone array  606  may further be arranged to capture location information of an audio source (e.g., voice, audible sound) and/or to assist in filtering background noise. Notably, in some embodiments the microphone array may consist of only a single microphone, rather than a plurality of microphones. 
     The network interface  608  may be configured to facilitate wireless and/or wired communication between various network devices, such as, in reference to  FIG.  5   , CR  522 , PBDs  532 - 538 , computing devices  504 - 508  in cloud network  502 , and other network microphone devices, among other possibilities. As such, network interface  608  may take any suitable form for carrying out these functions, examples of which may include an Ethernet interface, a serial bus interface (e.g., FireWire, USB 2.0, etc.), a chipset and antenna adapted to facilitate wireless communication, and/or any other interface that provides for wired and/or wireless communication. In one example, the network interface  608  may be based on an industry standard (e.g., infrared, radio, wired standards including IEEE 802.3, wireless standards including IEEE 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, 802.15, 4G mobile communication standard, and so on). 
     The user interface  610  of the network microphone device  600  may be configured to facilitate user interactions with the network microphone device. In one example, the user interface  610  may include one or more of physical buttons, graphical interfaces provided on touch sensitive screen(s) and/or surface(s), among other possibilities, for a user to directly provide input to the network microphone device  600 . The user interface  610  may further include one or more of lights and the speaker(s)  614  to provide visual and/or audio feedback to a user. In one example, the network microphone device  600  may further be configured to playback audio content via the speaker(s)  614 . 
     III. Example Systems and Methods 
     It may be desirable in some instances for a networked microphone device (“NMD”) to disable one or more (or all) of its microphones. It may further be desirable for one or more (or all) NMDs in a system of multiple NMDs to disable one or more (or all) of their microphones. For example, it may be desirable for any one or more (or all) of NMDs  512 ,  514 , and  516  to disable their microphones. 
     As described earlier, although an NMD may be configured to listen for a specific “wake word” or “wake phrase” to trigger the NMD to record spoken audio for analysis (and to take subsequent action based on or in response to the recorded audio), the microphones of an NMD are still typically always on, active, and listening for its “wake” word or phrase. It may be desirable for the NMD to disable its microphone(s) from even listening for the “wake word” or “wake phrase” when, for example, a user is sleeping, engaging in sensitive conversations either in person or via telephone or computer, or perhaps simply enjoying private family time (e.g., dinner, movies, story time with children). Not only may some users not want NMDs listening all of the time, some users may not want their NMDs (and/or other devices connected thereto) to interrupt their private time and activities with errant responses and/or actions. 
     And while users may be able to unplug, power-off, or physically disable and/or re-enable the microphone(s) of an NMD via manual activation of a switch or button on the NMD, in some instances, taking such manual action can be cumbersome, inconvenient, or otherwise undesirable. It may be particularly cumbersome, inconvenient, and/or otherwise undesirable to disable multiple NMDs if a user had to manually actuate a physical button or switch on each NMD in his or her home. 
     Because it is advantageous for an NMD to have the ability to disable and/or re-enable its microphone(s) without a user having to physically actuate a button/switch or power-off or unplug the NMD, in some embodiments, the NMD (or perhaps a computing device configured to control the NMD, e.g., computing device  504 ) is configured to disable the NMD microphone(s) in response to any one or more of: (i) determining that a reference device is in a particular state; (ii) receiving a voice command via the microphone(s) of the NMD; and (iii) receiving a command via a network interface of the NMD. And in some embodiments, the NMD (or perhaps a computing device configured to control the NMD, e.g., computing device  504 ) is additionally or alternatively configured to enable (or re-enable) the NMD microphone(s) in response to any one or more of: (i) determining that a reference device is in a certain state; and (ii) receiving a command via a network interface of the NMD. Example reference devices include lights, garage doors, locks, networked media playback systems, televisions, thermostats, home alarm systems, other household sensors (e.g. motion sensors, audio sensors, light sensors, or other sensors). 
     In some embodiments, an NMD is configured to disable and/or re-enable its microphone(s) based on a state of another device, referred to as a “reference” device in the examples disclosed herein. In operation, the NMD (or perhaps another device in communication with the NMD) determines whether a reference device is in a particular state, and then the NMD disables its microphone(s) in response to determining that the reference device is in that particular state. 
     In some embodiments, determining the state of the first reference device may include querying the device for its state information or monitoring the first reference device&#39;s state information. Determining the state of the first reference device may additionally or alternatively include receiving a message via a network interface of the NMD, where the message indicates that the first reference device is in the specific state. In operation, such a message could be sent by the first reference device or a computing device controlling and/or monitoring the first reference device. Other examples of determining a state may exist, too. This may be desirable in scenarios where the user may want to disable the microphone of one of the NMDs  512 ,  514 , and  516  when the first reference device performs a particular action or enters a particular state. 
     In operation, communication between an NMD and a reference device to convey state information or state change information can occur in multiple ways. 
     In some embodiments, communication of state information between the NMD and the reference device may occur directly (or at least substantially directly) between the NMD and the reference device. For example, with reference to  FIG.  5   , if the NMD is NMD  512  and the reference device is PBD  532 , then communication of state information between NMD  512  and PBD  532  may occur in a peer-to-peer or similar fashion over communication means  546 . As described earlier, communication means  546  may include one or more of for example, Bluetooth™ (IEEE 802.15), NFC, Wireless direct, and/or Proprietary wireless, among other possibilities including but not limited to Ethernet, WiFi (IEEE 802.11), and other wired or wireless communication protocols and methods. 
     In some embodiments, communication of state information between the NMD and the reference device may occur via one or more intermediary devices. For example, with reference to  FIG.  5    again, if the NMD is NMD  512  and the reference device is PBD  532 , then communication of state information between NMD  512  and PBD  532  may occur through one or more intermediary devices, including but not limited to one or more of computing device  506 , computing device  508 , and/or computing device  504 . For example, PBD  532  may communicate its current state to computing device  506  via communication path  544 , computing device  506  may communicate the current state of PBD  532  to computing device  504  over one or more public or private network links, and then computing device  504  may communicate the current state of PBD  532  to NMD  512  via communication path  542 . 
     In some embodiments, a first computing device may monitor and/or control the state of a reference device, and then communicate state changes (and/or perhaps other state information) of the reference device to a second computing device configured to control the NMD, e.g., to control or command the NMD to disable/enable the NMD&#39;s microphone(s). 
     In one example, with reference to  FIG.  5   , computing device  506  monitors the state of PBD  532 . When a user instructs PBD  532  to play certain media content (e.g., by entering a command via CR  522  or speaking a command via an NMD  516 ), PBD  532  (i) plays the requested media content in response to the user command, and (ii) perhaps additionally informs computing device  506  that it is playing media content (and perhaps that it is playing particular media content) by sending a message or other communication to computing device  506  via communication path  544 . The message or other communication that PBD  532  sends to computing device  506  may comprise state information and/or state change information for PBD  532 . In response to receiving the state and/or state change information from PBD  532 , computing device  506  updates a state table (or similar database or datastore) associated with PBD  532  and/or communicates the state and/or state change to one or more other computing devices, e.g., computing device  504 , computing device  508 , or perhaps even directly to NMD  512 . 
     In a related example, again with reference to  FIG.  5   , computing device  506  controls the state of PBD  532 . When a user instructs PBD  532  to play certain media content (e.g., by entering a command via CR  522  or speaking a command vian NMD  516 ), then CR  522  (or perhaps NMD  516  in the case of the voice command) sends a message or other communication to computing device  506  to request that PBD  532  play the requested media content. Computing device  506  may optionally verify whether PBD  532  is able and/or authorized to play the requested media content. Then, computing device  506  instructs PBD  532  to play the requested media content via one or more messages, commands, or other communications via communications path  544 . PBD  532  may confirm receipt of the command(s) received from computing device  506  and also confirm successful execution of the command(s) (i.e., confirm that it is playing the requested media content) by sending one or more response messages to computing device  506  via communication path  544 . In response to receiving the one or more response messages and/or the state and/or state change information from PBD  532 , computing device  506  updates a state table (or similar database or datastore) associated with PBD  532  and/or communicates the state and/or state change to one or more other computing devices, e.g., computing device  504 , computing device  508 , or perhaps even directly to NMD  512 . 
     Other examples of communicating state information and/or state change information of a reference device(s) either directly or indirectly between the reference device and the NMD are possible as well, including but not limited to scenarios where (i) one or more intermediate computing devices (e.g., computing device  506  individually or in combination with other computing devices) monitor or control the state or state changes of the reference device (e.g., one or more of PBDs  532 - 538 ) and advise an NMD of the state or state change information for the reference device, where the NMD enables/disables its microphone(s) based on the state and/or state changes of the reference device; (ii) one or more intermediate computing devices (e.g., computing device  506  individually or in combination with other computing devices) monitor or control the state or state changes of the reference device (e.g., one or more of PBDs  532 - 538 ) and advise one or more computing devices controlling the NMD (e.g., computing device  504  individually or in combination with other computing devices) of the state or state change information for the reference device, where the one or more computing devices controlling the NMD in turn instruct/command the NMD to enable/disable its microphone(s) based on the state and/or state changes of the reference device; and (iii) one or more intermediate computing devices (e.g., any of computing devices  504 ,  506 , and  508  individually or in combination with other computing devices) pass state or state change information of the reference device (e.g., one or more of PBDs  532 - 538 ) received from the reference device to an NMD (e.g., one or more of NMDs  512 - 516 ), where the NMD in turn enables/disables it microphone(s) based on the state and/or state changes of the reference device passed from the reference device to the NMD via the intermediate computing device(s). 
     The above-described examples relate to different ways of determining the state (or perhaps state change) of a reference device where the reference device is a playback device, but the above-described state or state change determination scenarios are equally applicable to examples where the reference device is something other than a playback device, such as a lighting system, home-security system, motion sensor, camera, alarm clock, television, thermostat, appliance, or any other device for which a state or state change can be monitored and/or controlled. 
     In some example embodiments, the first reference device is a lighting system. In such an example, the NMD (or perhaps a computing system configured to control the NMD, e.g., computing device  504  or another computing device) may be configured to determine whether the lighting system is in a particular state, e.g., whether the lights in a room are on or off. And if the NMD (or the computing system configured to control the NMD) determines that the lights in the room are off, the NMD disables its microphone(s). If the lighting system is network-connected, the NMD (or the computing system configured to control the NMD) can determine whether the lights are off by, for example, monitoring the state of a lighting controller configured to control the lights in the room, querying the lighting controller to obtain the state of the lights in the room, and/or receiving a message from the lighting controller. If the lighting system is not network-connected, the NMD (or the computing system configured to control the NMD) can determine whether the lights are off by, for example, monitoring a light sensor. The light sensor could be a component of the NMD or another networked device. 
     In another example embodiment, the first reference device is a media playback system or at least one media playback device of a media playback system, e.g., the media playback system  100  of  FIG.  1   , the one or more playback devices  200  of  FIG.  2   , or any other media playback system. In this scenario, the user may want to disable the microphone(s) of the NMD when the media playback system is playing a particular type of media, such as a relaxing song or audio content from a movie being shown on a television or other display device. In this example, the NMD (or another local or remote computing device) (i) determines whether the media playback system is in a particular state (i.e., whether one or more media playback devices of the system are playing a particular type of media), and (ii) disables the microphone(s) of the NMD in response to determining that the media playback system is in the particular state (i.e., in response to determining that one or more media playback devices of the system are playing the particular type media). 
     The particular state of the media playback system may include playing particular media content or a type of media content. The particular media content or type of media content may include audio or video content such as a yoga video or a deep meditation soundtrack that could easily be disrupted by the NMD erroneously responding to query or activating/deactivating some other device in the user&#39;s home (e.g., turning on the lights). Thus, it may be particularly desirable for the networked microphone device to disable the microphone when the media playback device (or media playback system) is playing such content. 
     The particular state of the media playback system may additionally or alternatively include the media playback device being above or below a particular volume level, or perhaps within a particular volume range. For example, the NMD may be configured to disable its microphone(s) in response to determining that the volume level of a media playback device (or a system of media playback devices) is above a certain threshold where it might be too loud for voice commands to be heard anyway. Additionally or alternatively, the NMD may be configured to disable its microphone(s) in response to determining that the volume level of a media playback device (or a system of media playback devices) is below a certain threshold volume level, for example, when the media playback device is playing media content late at night at a low volume, or when the media playback device is configured in a “night mode” where louder sounds in television shows, movies, or music are attenuated to reduce the likelihood of disturbing neighbors, roommates, or other family members in the house while watching shows or listening to music late at night. Additionally or alternatively, the NMD may be configured to disable its microphone(s) in response to determining that the volume level of a media playback device (or system of media playback devices) is within a certain threshold range while the media playback device (or system) is playing specific content, e.g., when the media playback device (or system) is playing relaxing music at a volume that suggest the user is sleeping, meditating, or otherwise relaxing and may not wish to be disturbed by the NMD responding audibly or otherwise taking an unexpected action in response to mistaking hearing its “wake” word/phrase. 
     Additionally, the particular state of the media playback system may also include the media playback system entering a particular media playback mode. For example, if the NMD (or another computing device) determines that the media playback system is in a “party mode” state where all of the media playback devices are configured to playback the same audio content in synchrony with each other, then the NMD may disable its microphone(s). It may be desirable to disable the microphone(s) of the NMD if the media playback system enters a particular playback mode such as a “party” mode or other type of playback mode. In this example, it may be desirable to disable the microphone(s) of the NMD to prevent the NMD from responding to or taking other action after mistaking hearing its “wake” word/phrase, which may disrupt media playback by the media playback system and thereby result in a less enjoyable social gathering for a user&#39;s guests. 
     In some embodiments, the NMD and first reference device may be contained in the same enclosure. For example, if the first reference device is a media playback device, and if the NMD is a component of the media playback device, then the NMD can disable and/or re-enable its microphone(s) based on the particular state of the media playback device. Or to state it another way, a media playback device equipped with one or more microphones can disable its one or more microphones based on one or more of (i) the type of content that the media playback device is playing and/or (ii) the playback mode of the media playback device (e.g., a party mode or other playback mode). 
     In some embodiments, the first reference device is a clock. The clock may be a hardware and/or software component of the NMD, a media playback device, or another device that the NMD (or other computer) can query, monitor, or receive some time/date message from. In such embodiments, the NMD (or other computer) can determine whether the clock is in a particular state (e.g., that the time of day is within a certain range, such as between 11 pm and 7 am), and in response to determining that the clock is in the particular state, disable the microphone(s) of the NMD. Other times of day or time ranges are also suitable. In this example, it may be desirable to disable the microphone of the NMD because the user may generally sleep during the time range and thus would not want the NMD to be listening to sounds in his or her bedroom or potentially be awoken by an erroneous activation of the NMD and/or awoken by the NMD taking some action in response to an erroneous trigger (e.g., turning on the lights in the room or playing music). 
     In some embodiments, the first reference device may include another NMD. In this embodiment, it may be desirable for the NMD (or a computing device configured to control the NMD) to determine whether the other NMD is in a particular state, and disable the microphone(s) of the NMD in response to determining that the other NMD is in the particular state. For example, the NMD may be configured to determine whether the microphone(s) of the other NMD has been disabled, and then disable its own microphone(s) in response to determining that the microphone(s) of the other NMD has been disabled. For example, if a user&#39;s home contains multiple NMDs and the user disables the microphone on one NMD, it may be desirable to disable all the microphones of the other NMDs, too. 
     Thus, in some of the above-described embodiments, the NMD (or a computer associated with the NMD): (i) determines whether the first reference device is in a first state, and (ii) disables the NMD&#39;s microphone(s) in response to determining that the first reference device is in the first state. In some embodiments, the NMD (or a computer associated with the NMD) may additionally (i) determine whether the first reference device is in a second state, and (ii) re-enable the NMD&#39;s microphone(s) in response to determining that the first reference device is in the second state. 
     In operation, the second state may be related to the first state. For example, if the first state is lights off, the second state might be lights on (or lights not off). Alternatively, the second state may not directly relate to the first state. For example, if the first state is lights off, the second state might be time of day is between 7 am and 11 pm. Further, in some embodiments, the first state may be a state of the first reference device, and the second state may be a state of a second reference device. In some embodiments, the NMD could be configured to enable/disable its microphone(s) based on additional multiple states of additional multiple disparate reference devices. 
     As described earlier, determining the state of a reference device (a first or a second reference device) may include querying the reference device for state information or receiving a message via a network interface of the first NMD (or other computing device configured to control the first NMD, e.g., computing device  504 ), where the message indicates a state of the reference device. In operation, such a message could be sent by the reference device or a computing device controlling and/or monitoring the reference device. Other examples of determining a state may exist, too. This may be desirable to a user because the user may want to enable the previously-disabled microphone(s) of one of the NMDs  512 ,  514 , and  516  when the first or second (or third, fourth, and so on) reference device performs a particular action or enters a particular state. 
     For example, the NMD may be connected to or in communication with a reference device, such as a network-connected lighting system. In this example, the NMD may determine the state of the network-connected lighting system (e.g., lights-on state vs. lights-off state) and enable its microphone(s) if the lights are in the lights-on state. 
     In another example, the reference device may include a network-connected home security system. In this example, the NMD may determine the state of the network-connected home security system and enable its microphone(s) if the home security system is in an alarm-activated state. This may be particularly advantageous because enabling the NMD microphone(s) may allow a user to use the NMD to call the appropriate authorities in case of a break-in or fire. 
     In another example, the reference device may include an alarm clock or a device with an alarm clock function. In this example, the NMD may determine the state of the alarm clock (or whether a device with an alarm clock function is in a state where a wake-up alarm has been activated), and then activate the microphone(s) of the NMD in response to determining that the alarm clock (or the device with the alarm clock function) is in a wake-up alarm activated state. This functionality may be desirable for users who have configured the NMD to disable its microphone(s) while the user is sleeping, but who may want the NMD to enable (or re-enable) its microphone(s) when the user wakes up so that the user can then speak commands and/or request information from the NMD, e.g., turning on the lights, requesting weather information, playing a morning music playlist or news program. 
     In some embodiments, the NMD may additionally disable its microphone(s) in response to the user “snoozing” the alarm clock, or perhaps speaking a command to the NMD to instruct the NMD to snooze the alarm clock. For example, if the user hits a snooze button on the alarm clock, the alarm clock changes from a “wake up alarm has been activated” state to a “snooze” state. In some embodiments, the NMD may disable its microphone(s) in response to determining that the alarm clock is in the “snooze” state. The NMD may subsequently re-enable its microphone(s) in response to determining that the alarm clock has again changed to the “wake up alarm has been activated” state from the “snooze” state. Or alternatively, the NMD may simply disable its microphone(s) for some timeframe (e.g., 10 minutes) in response to receiving the voice command to snooze the alarm clock (or device with the alarm clock function), and then re-enable its microphone(s) after expiration of the timeframe. 
     In yet another example, the reference device may include a network-connected motion sensor, such as an infrared motion sensor, vibration sensor, camera, or any other type of motion sensor now known or later developed, including but not limited to standalone motion sensors and/or other devices that incorporate or otherwise contain motion sensors, e.g., accelerometer, gyroscopic, or other types of motion sensors. In this example, the NMD may determine the state of the network-connected motion sensor and enable its microphone(s) if the motion sensor is in a motion-detected state. For example, in rooms where the NMD has previously disabled its microphone(s) based on the state of one or more devices, the NMD may be configured to enable (or re-enable) its microphone(s) upon detecting that someone has entered the room. In yet another example, the reference device may include a motion sensor, where the NMD comprises the motion sensor, and where the NMD may be configured to disable or enable its microphone(s) based on the state of the motion sensor, e.g., enabling the microphone(s) in response to determining that the motion sensor is in a motion detected state and disabling the microphone(s) in response to determining that the motion sensor is not in the motion detected state (or perhaps vice versa). 
     In yet another example, the reference device may include a proximity detector, such as a Bluetooth™ Low Energy (BTLE) or Near Field Communication (NFC) or any other type of proximity detector now known or later developed, including but not limited to standalone proximity sensors and/or other devices that incorporate or otherwise contain proximity sensors. In this example, the NMD may determine the state of the proximity sensor and enable (or perhaps disable) its microphone(s) when the proximity sensor is in a motion-detected or presence-detected state. For example, in such embodiments, a user could wave his or her BTLE or NFC-equipped smartphone at a NMD, and the NMD could change its state (e.g., from disabled to enabled or from enabled to disabled) in response to detecting the motion or presence via the proximity detector. 
     In addition to disabling and enabling the microphone(s) of an NMD in response to determining the state of one or more reference devices, it also may be advantageous in some instances to disable and/or enable the microphone(s) of the NMD in response to receiving a command to disable and/or enable the microphone(s) of the NMD. In operation, the NMD may receive the command via one of (i) the microphone(s) of the NMD and/or (ii) a network interface of the NMD. 
     In some embodiments, the NMD may receive a command to disable its microphone(s) via the microphone(s) of the NMD. In such embodiments, the command may include a voice command to disable the microphone(s) of the NMD. For example, a user may want to disable the microphone(s) of the NMD without manually actuating a physical button on the NMD or powering off the NMD. For example, the user may speak a voice command such as “device, disable microphone,” or “device, stop listening.” And in response to receiving the voice command, the NMD disables its microphone(s). 
     Additionally or alternatively, the NMD may receive a command to disable its microphone(s) via a network interface of the NMD. 
     In some embodiments, the NMD may receive such a command from a controller device operable to configure and/or control the NMD. For example, the controller device may be a smartphone, tablet computer, or other computing device executing a user interface program operable to configure and/or control the NMD. In operation, the controller device sends a “Turn Off Microphone” or “Disable Microphone” or similar command to the NMD in response to receiving a user input via the user interface to disable the microphone(s) of the NMD. 
     In further embodiments, the NMD may receive such a command from another NMD or any other computing device operable to send a command over a network (e.g., a LAN, WAN, or other network infrastructure) to the NMD that causes the NMD to disable its microphone(s). 
     In some embodiments, the NMD is configured to disable its microphone(s) in response to any one or more of: (i) determining that a reference device is in a particular state; (ii) receiving a voice command via the microphone(s) of the NMD; and (iii) receiving a command via a network interface of the NMD. And in some embodiments, the NMD is additionally or alternatively configured to enable (or re-enable) its microphone(s) in response to any one or more of: (i) determining that a reference device is in a certain state; and (ii) receiving a command via a network interface of the NMD. 
     For example, the user may want to enable the microphone(s) of the NMD after issuing a command to disable the microphone(s) of the NMD. In operation, the user may speak a voice command to disable the microphone(s), but then later decide that he or she would like to speak commands to the NMD to cause the NMD (or perhaps a media playback device communicatively coupled to the networked microphone device) to play music. So to cause the NMD to enable its microphone(s), the user may issue a command from the controller device that to enable the microphone(s) of the NMD, thereby causing the NMD to enable (or re-enable) its microphone(s) in response to receiving the command from the controller via the network interface of the NMD. 
     In another example, an NMD may receive a command to disable the microphone(s) of the NMD from a user via one of (i) the microphone(s) of the NMD or (ii) a network interface of the NMD. After the microphone is disabled, a reference device may subsequently enter a particular state that causes the NMD to enable its microphone(s) in response to determining that the reference device has entered that particular state. For example, a user may disable the microphone via the microphone by stating “device, disable microphone.” Afterwards, a home security system may enter an alarm-activated state. In operation, the NMD (or a computer associated with the NMD) determines that the home security system has entered the alarm-activated state, and the NMD then enables its microphone(s) in response to determining that the home security system is in the alarm-activated state. One advantage to re-enabling the microphone(s) of the NMD after the user previously disabled the microphone(s) in this scenario is that, re-enabling the microphone(s) in response to determining that the home security system has entered the alarm-activated state enables the user to call authorities for help or speak other commands to the NMD. 
     In another example, the NMD (a first NMD) may be communicatively coupled to a one or more other NMDs (at least a second NMD). In embodiments where the NMD is a media playback device (or at least a component of a media playback device), the communicative coupling may include the first and second NMDs configured in a synchrony group, a bonded group, a consolidated group, or other type connected or combined configuration described herein. 
     The first NMD may receive a command to disable its microphone(s) from a user via one of the microphone of the NMD or a network interface of the NMD. In response to receiving the command to disable its microphone(s), the first NMD disables its microphone(s) and sends a command or message to the second NMD that causes the second NMD to disable its microphone(s), too. In this manner, the second NMD disables its microphone(s) in response to (i) determining that the first NMD (i.e., reference device) has changed to a “microphone disabled” state and/or (ii) receiving a command from the first NMD to disable its microphone(s). 
     After the first and second NMDs have disabled their microphones, the user may actuate a physical button or switch on one of the NMDs that in turn causes both the first and second NMD to re-enable their microphones. In one example, the user actuates the physical button or switch on the second NMD, which causes the second NMD to re-enable its previously-disabled microphone(s). In operation, the second NMD may then re-enable its previously-disabled microphone(s) and send a command or message to the first NMD that causes the first NMD to re-enable its previously-disabled microphone(s), too. In this manner, the first NMD enables its microphone(s) in response to (i) determining that the second NMD (i.e., reference device) has changed to a “microphone enabled” state and/or (ii) receiving a command from the second NMD to enable its microphone(s). This feature is advantageous for a user who wishes to enable/disable the microphones of all connected NMDs when he or she enables/disables the microphone(s) on one NMD of his or her NMD system. 
     In some examples, the NMD may be (i) a media playback device equipped with microphones, (ii) a component of a media playback device, and/or (iii) associated with a media playback device, where the NMD is one of a plurality of devices in a media playback system comprising the NMD and one or more media playback devices. 
     As mentioned earlier, in some embodiments, sets of individual media playback devices can be configured in different types of groupings, including but not limited to (i) a zone group where all of the media playback devices are configured to play back the same media content in synchrony, (ii) a bonded playback device comprising a stereo grouping of playback devices where a first media playback device is configured to play a right stereo channel of media content and a second media playback device is configured to play a left stereo channel of the media content, (iii) a bonded playback device comprising a quadraphonic grouping of playback devices where first, second, third, and fourth media playback devices are configured to play first, second, third, and fourth channels of the media content, respectively, (iv) a 5.1 surround mode grouping, where first, second, third, fourth, and fifth media playback devices are each configured to play an assigned one of five channels of media content, e.g., right front, center, left front, right rear, and left rear, or other 5-channel arrangement, (v) a 7.1 surround mode grouping, where first, second, third, fourth, fifth, six, and seventh media playback devices are each configured to play an assigned one of seven channels of media content, e.g., right front, center, left front, right side, left side, right rear, and left rear, or other 7-channel arrangement, (vi) a consolidated playback device comprising a grouping of media playback devices, where a first media playback device is configured to play a first assigned frequency range of media content (or perhaps assigned frequency range of assigned channel of media content) and a second media playback device is configured to a play a second assigned frequency range of media content (or perhaps assigned frequency range of assigned channel of media content), or other frequency-division assignment arrangement, (vii) a zone group comprising two or more consolidated playback devices; (viii) a bonded playback device comprising two or more consolidated playback devices; (ix) a zone group comprising two or more bonded playback devices, where each bonded playback device comprises two or more consolidated playback devices; (x) a zone group comprising any two or more of a standalone media playback device, a consolidated playback device, or a bonded playback device, in any combination; and/or (xi) any combination of the above-described groupings. In operation, any of the above-described groupings may correspond to a particular grouping state of a media playback device (or media playback system). 
     Additionally, as mentioned previously, in some embodiments, the NMD may be any of (i) a media playback device equipped with microphones, or (ii) a component of a media playback device. In any such embodiments, when one NMD in any of the above-described groupings disables its microphone(s), then one or more other NMDs in the grouping (or perhaps all the NMDs in the grouping) disable their microphones. And when one NMD in any of the above-described groupings enables it microphone(s), then one or more other NMDs in the grouping (or perhaps all the NMDs in the grouping) enable their microphones. 
     Further, and as mentioned previously, in some embodiments an NMD is associated with a media playback device or perhaps a grouping of media playback devices, where the NMD is one of a plurality of devices in a media playback system comprising one or more NMDs and one or more media playback devices in any of the above-described groupings. In any such embodiments, when one NMD associated with a grouping of media playback devices disables its microphone(s), then one or more other NMDs associated with the grouping of media playback devices (or perhaps all the NMDs associated with the grouping) disable their microphones. And when one NMD associated with the grouping of media playback devices enables its microphone(s), then one or more other NMDs associated with the grouping of media playback devices (or perhaps all the NMDs associated with the grouping) enable their microphones. 
     Still further, in some embodiments, any of the above-described groupings may include one or more NMDs in the grouping (e.g., either as a media playback device equipped with microphones or as a component of a media playback device) and one or more NMDs associated with the grouping. In any such embodiments, when any NMD in a grouping and/or associated with the grouping disables its microphone(s), then one or more other NMDs in the grouping and/or associated with the grouping (or perhaps all the NMDs in and/or associated with the grouping) disable their microphones. And when one NMD in and/or associated with the grouping enables its microphone(s), then one or more other NMDs in and/or associated with the grouping (or perhaps all the NMDs in and/or associated with the grouping) enable their microphones. 
     Some embodiments where the NMD is a media playback device with a microphone (or perhaps a component of a media playback device) are additionally configured to, at least in some situations, mute the speakers of the media playback device when the microphone is disabled and vice versa. Further, when such NMDs are configured in any of the above-described group arrangements, in some embodiments, disabling one NMD&#39;s microphone(s) in the group causes one or more other NMDs in the group (or perhaps all the NMDs in the group) to both (i) disable their microphone(s) and (ii) mute their speaker(s). Similarly, when such NMDs are configured in any of the above-described group configurations, in some embodiments, muting one NMD&#39;s speaker(s) in the group causes one or more other NMDs in the group (or perhaps all the NMDs in the group) to both (i) mute their speaker(s) and (ii) disable their microphone(s). 
     Additionally, in some embodiments where the NMD is a media playback device with a microphone (or perhaps a component of a media playback device), the media playback device (or at least the NMD therein) is configured to enable or disable its microphone(s) based on whether the device is a member of a zone group, a member of a consolidated playback device, and/or a member of a bonded playback device. In one such example embodiment, a zone group comprises three media playback devices, where each media playback device comprises one or more microphone(s). In this example, when the three media playback devices are initially grouped into the zone group, the primary playback device (i.e., master or head-end device) is configured to enable its microphone(s), and the two secondary playback devices (i.e., slave or subtending devices) are configured to disable their microphones. For example, a Sonos PLAYBAR and two Sonos PLAY:1 devices can be grouped into a zone group. Upon initial grouping into the zone group, the PLAYBAR determines that it is a master of the zone group and enables it microphones, and each PLAY:1 device determines that it is a slave to the PLAYBAR in the zone group and disables its microphones. Other scenarios of enabling and/or disabling microphones based on grouping of playback devices and NMDs are within the scope and spirit of the embodiments envisioned herein as well. 
     In some embodiments where the NMD is a media playback device with a microphone (or perhaps a component of a media playback device), the media playback device may be configured to disable its microphone based on its assigned zone name. For example, in some embodiments, a media playback device disables its microphone(s) in response to determining that it has been placed in a bedroom or baby room based on the media playback device having been assigned to a “Bedroom” or “Baby Room” zone or zone grouping, or perhaps other zone or room name corresponding to a location or room in a house where the user expects or desires more privacy. 
     Further, in some embodiments where the NMD is associated with a media playback device, the NMD is additionally configured to, at least in some situations, disable its microphone(s) when the speaker(s) of the associated media playback device has been muted. Further, when such NMDs are associated with two more media playback devices configured in any of the above-described group arrangements, in some embodiments, disabling the NMD&#39;s microphone(s) causes one or more associated media playback devices in the group (or perhaps all the media playback devices in the group) to mute their speaker(s). Similarly, when such NMDs are associated with two more media playback devices configured in any of the above-described group arrangements, in some embodiments, muting one of the associated media playback device&#39;s speaker(s) in the group causes both (i) one or more other media playback devices in the group (or perhaps all the media playback devices in the group) to mute their speaker(s) and (ii) the associated NMD to disable its microphone(s). 
     In another example, consistent with the embodiments discussed herein, an NMD may disable its microphone(s) in response to determining that the lights in the room are turned off (i.e., lights in “off” state). However, the user may want to control a media playback system via commands spoken to the NMD even though the lights are off. In this scenario, the user may open a user interface for the NMD running on a controller device of the NMD and select an “Enable Microphone” button via the user interface, thereby causing the controller to send a command that causes the NMD to enable its microphone(s). 
     Many of the above-described examples are scenarios where the microphone(s) of an NMD is disabled or enabled in response to determining that a single reference device is in a particular state (or not in that particular state). In some embodiments, the microphone(s) of an NMD is disabled in enabled in response to determining that two more reference devices are in a particular state. 
     In one example, the first reference device is a lighting system, the second reference device is an alarm clock, and the NMD is configured to disable its microphone(s) in response to a determination (by the NMD or a device controlling the NMD) that (i) the lighting system is in a “lights off” state and (ii) the alarm clock in a “wake up alarm set but not yet activated” state, which may indicate that the user is sleeping. 
     In another example, the reference device is a lighting system, the second reference device is a media playback device, and the NMD is configured to disable its microphone(s) in response a determination (by the NMD or a device controlling the NMD) that (i) the lighting system is in a “lights dimmed below a certain threshold” state and (ii) the media playback device is in a “playing a relaxation playlist” state, which may indicate that the user is meditating or otherwise relaxing. 
     In yet another example, the first reference device is a telephone, the second reference device is a motion sensor in a home office, and the NMD is configured to disable its microphone(s) in response a determination (by the NMD or a device controlling the NMD) that (i) the telephone is in a “phone call active” state and (ii) the motion sensor in the user&#39;s home office is in a “motion detected” state, which may indicate that the user is conducting a private or confidential telephone call where it might be undesirable for an NMD to have its microphone(s) enabled. 
     Enabling or disabling microphones(s) of an NMD based on more complicated state combinations of three, four, or more separate reference devices could be implemented according to the teachings herein, too. 
     Method  700  shown in  FIG.  7    presents an embodiment of a method that can be implemented within an operating environment including or involving, for example, the media playback system  100  of  FIG.  1   , one or more playback devices  200  of  FIG.  2   , one or more control devices  300  of  FIG.  3   , the user interface of  FIG.  4   , the configuration shown in  FIG.  5   , and/or the NMD shown in  FIG.  6   . Method  700  may include one or more operations, functions, or actions as illustrated by one or more of blocks  702 - 706 . Although the blocks are illustrated in sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation. 
     In addition, for the method  700  and other processes and methods disclosed herein, the flowchart shows functionality and operation of one possible implementation of some embodiments. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by one or more processors for implementing specific logical functions or steps in the process. The program code may be stored on any type of computer readable medium, for example, such as a storage device including a disk or hard drive. The computer readable medium may include non-transitory computer readable medium, for example, such as tangible, non-transitory computer-readable media that stores data for short periods of time like register memory, processor cache and Random Access Memory (RAM). The computer readable medium may also include non-transitory media, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, for example, or a tangible storage device. In addition, for the method  700  and other processes and methods disclosed herein, each block in  FIG.  7    may represent circuitry that is wired to perform the specific logical functions in the process. 
     Method  700  begins at block  702 , which includes a first NMD (or alternatively a computing device configured to control the first NMD), while a microphone of the first networked microphone device is enabled, determining whether a first reference device is in a specific state. In some embodiments, determining whether a first reference device is in a specific state includes querying the first reference device to obtain its current state. In some embodiments, querying the first reference device to obtain its current state may include obtaining a state variable, state table, or table of state variables, or perhaps other configuration or state information of the reference device directly or indirectly from the reference device. 
     For example, the NMD (or a computing device configured to control the NMD) may obtain the state information (via a variable, table, table of variable, or other form) from the reference device over a wired or wireless LAN, WAN, ad hoc network, or other communications link. The NMD (or a computing device configured to control the NMD) may additionally or alternatively obtain the state information in any of the above-described forms from a computing device configured to control the reference device. In some embodiments, the computing device configured to control the NMD may store state information of the reference device and receive updates to the reference device&#39;s state directly or indirectly from the reference device. In some embodiments, the computing device configured to control the NMD may be the same computing device configured to control/monitor the reference device. This may be the case in scenarios where the NMD is a first media playback device and the reference device is a second media playback device. This may also be the case in scenarios where a single computing system is configured to control/monitor NMDs and reference devices, which may the case in embodiments where the computing system configured to control/monitor NMDs and reference devices is a local and/or cloud-based home automation server or application service. 
     In some embodiments, determining whether a first reference device is in a specific state includes receiving a first message (or command) via a network interface of the first NMD, wherein the message (or command) indicates that the first reference device is in the specific state. In still further embodiments, determining whether the first reference device is in the specific state includes querying a computing device that is configured to monitor or control the first reference device. And in still further embodiments, determining whether the first reference device is in the specific state includes the NMD receiving a first message (or command) via its network interface from a computing device configured to monitor or control the first reference device, where the first message (or command) indicates that the first reference device is in the specific state. 
     In some embodiments, the first reference device is any of (i) a reference device that is separate from the networked microphone device, (ii) a reference device that is a component of the networked microphone device, (iii) a reference device that is a component of a media playback device, (iv) a second NMD (or system of NMD s), and/or (v) a media playback device (or system of playback devices). The first reference device may be any other type of reference device disclosed or described herein. 
     In some example embodiments, the first reference device comprises one or more lights, and the specific state of the first reference device comprises one or more lights that are in a powered-off state. In other example embodiments, the first reference device comprises a media playback device, and the specific state of the media playback device comprises the media playback device configured to play content in synchrony with one or more additional media playback devices. In yet other example embodiments, the first reference device comprises a media playback device associated with the first NMD, wherein the specific state of the media playback device is the media playback device playing a first type of media content. 
     Alternatively, in some embodiments, the first reference device comprises a second NMD, wherein the state of the second NMD comprises a microphone of the second NMD is disabled. 
     Next, method  700  advances to block  704 , which includes, in response to determining that the first reference device is in the specific state, disabling the microphone of the first NMD. 
     Next, method  700  may additionally advance to optional block  706 , which includes, while the microphone of the first NMD is disabled, determining that the first reference device is no longer in the specific state. In operation, determining that the first reference device is no longer in the specific state may be performed in substantially the same as determining that the first reference device is in the specific state, e.g., via query, message, command, and so on. 
     Method  700  may then advance to optional block  708 , which includes, in response to determining that the first reference device is no longer in the specific state, enabling the microphone of the first NMD. 
     Alternatively, instead of method  700  advancing to optional block  706 , method  700  may instead advance to optional block  710 , which includes, while the microphone of the first NMD is disabled, determining that a second reference device is in a particular state. 
     In some embodiments, the second reference device comprises a home security system, wherein the particular state of the home security system comprises an alarm-activated state. In other embodiments, the second reference device comprises a motion sensor, wherein the particular state of the motion sensor comprises a motion-detected state. 
     Next, method  700  may additionally advance to optional block  712 , which includes, in response to determining that the second reference device is in the particular state, enabling the microphone of the first networked microphone device. 
     Method  800  shown in  FIG.  8    presents an embodiment of a method that can be implemented within an operating environment including or involving, for example, the media playback system  100  of  FIG.  1   , one or more playback devices  200  of  FIG.  2   , one or more control devices  300  of  FIG.  3   , the user interface of  FIG.  4   , the configuration shown in  FIG.  5   , and/or the networked microphone device of  FIG.  6   . Method  800  may include one or more operations, functions, or actions as illustrated by one or more of blocks  802 - 804 . Although the blocks are illustrated in sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation. 
     In addition, for the method  800  and other processes and methods disclosed herein, the flowchart shows functionality and operation of one possible implementation of some embodiments. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by one or more processors for implementing specific logical functions or steps in the process. The program code may be stored on any type of computer readable medium, for example, such as a storage device including a disk or hard drive. The computer readable medium may include non-transitory computer readable medium, for example, such as tangible, non-transitory computer-readable media that stores data for short periods of time like register memory, processor cache and Random Access Memory (RAM). The computer readable medium may also include non-transitory media, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, for example, or a tangible storage device. In addition, for the method  800  and other processes and methods disclosed herein, each block in  FIG.  8    may represent circuitry that is wired to perform the specific logical functions in the process. 
     Method  800  begins at block  802 , which includes a first NMD, while a microphone of the first NMD is enabled, receiving a command to disable the microphone of the first NMD via one of (i) the microphone of the NMD or (ii) a network interface of the NMD. 
     In some embodiments, the command received via the microphone of the NMD comprises a voice command received via the microphone of the NMD. In other embodiments, the command received via the network interface of the NMD comprises a command received from a controller. In some embodiments, the controller is a device separate from the NMD. 
     Next, method  800  advances to block  804 , which includes, in response to receiving the command to disable the microphone of the NMD via one of the microphone of the NMD or the network interface of the NMD, disabling the microphone of the NMD. 
     Next, method  800  may additionally advance to optional block  806 , which includes, while the microphone of the first NMD is disabled, determining that a first reference device is in a specific state. 
     Method  800  may then advance to optional block  808 , which includes, in response to determining that the first reference device is in the specific state, enabling the microphone of the first NMD. 
     IV. Conclusion 
     The description above discloses, among other things, various example systems, methods, apparatus, and articles of manufacture including, among other components, firmware and/or software executed on hardware. It is understood that such examples are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of the firmware, hardware, and/or software aspects or components can be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and/or firmware. Accordingly, the examples provided are not the only way(s) to implement such systems, methods, apparatus, and/or articles of manufacture. 
     Additionally, references herein to “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one example embodiment of an invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As such, the embodiments described herein, explicitly and implicitly understood by one skilled in the art, can be combined with other embodiments. 
     The specification is presented largely in terms of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing devices coupled to networks. These process descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understood to those skilled in the art that certain embodiments of the present disclosure can be practiced without certain, specific details. In other instances, well known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the forgoing description of embodiments. 
     When any of the appended claims are read to cover a purely software and/or firmware implementation, at least one of the elements in at least one example is hereby expressly defined to include a tangible, non-transitory medium such as a memory, DVD, CD, Blu-ray, and so on, storing the software and/or firmware.