Acoustic topology characterization for media playback system components

Abstract

A media playback system can be used to characterize acoustic topology' among multiple playback devices. Each device sequentially plays an acoustic signal while others detect the sound. An acoustic separation parameter is obtained for each device pair based on the detected sound data. The system characterizes an acoustic topology of the playback devices using these parameters, representing the acoustic relationships between devices rather than physical distances. This topology enables the system to make intelligent decisions about device grouping, audio routing, and playback settings. The system can change device states based on the acoustic topology, optimizing audio performance and user experience in multi-room setups. This approach allows for more intuitive and context-aware audio playback, voice control, and device interactions in complex acoustic environments.

Description

Attorney Docket No 24-0201-PCTFortem Reference No. SNS.152WOACOUSTIC TOPOLOGY CHARACTERIZATION FOR MEDIA PLAYBACK SYSTEM COMPONENTSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Patent Application No. 63 / 700,357, filed September 27, 2024, and to U.S. Patent Application No. 63 / 700,397, filed September 27, 2024, each of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present technology relates to consumer goods and, more particularly, to methods, systems, products, features, services, and other elements directed to voice-controllable media playback systems or some aspect thereof.BACKGROUND

[0003] 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 a controller, for example, different songs can be streamed to each room that has a playback device, rooms can be grouped together for synchronous playback, or the same song can be heard in all rooms synchronously.

[0004] 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

[0005] Features, aspects, and advantages of the presently disclosed technology may be better understood with regard to the following description, appended claims, and accompanying drawings.

[0006] Figure 1A is a partial cutaway view of an environment having a media playback system configured in accordance with aspects of the disclosed technology.Attorney Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0007] Figure IB is a schematic diagram of the media playback system of Figure 1A and one or more networks.

[0008] Figure 2A is a functional block diagram of an example playback device.

[0009] Figure 2B is an isometric diagram of an example housing of the playback device of Figure 2A.

[0010] Figure 2C is a diagram of another example housing for the playback device of Figure 2A.

[0011] Figures 3A-3E are diagrams showing example playback device configurations in accordance w ith aspects of the disclosure.

[0012] Figure 4A is a functional block diagram of an example controller device in accordance with aspects of the disclosure.

[0013] Figures 4B and 4C are controller interfaces in accordance with aspects of the disclosure.

[0014] Figure 5 is a functional block diagram of certain components of an example network microphone device in accordance with aspects of the disclosure.

[0015] Figure 6A is a diagram of an example voice input.

[0016] Figure 6B is a graph depicting an example sound specimen in accordance with aspects of the disclosure.

[0017] Figure 7 is a functional block diagram of acoustic topology characterization components of a media playback system in accordance with aspects of the disclosure.

[0018] Figures 8A-9 illustrate example configurations of acoustic topology7characterization components of a media playback system in accordance with aspects of the disclosure.

[0019] Figures 10 and 11 illustrate example graphical representations of acoustic topologies in accordance with aspects of the disclosure.

[0020] Figures 12-15 are flow charts illustrating example methods for characterizing the acoustic topology a media playback system in accordance with aspects of the disclosure.

[0021] The drawings are for purposes of illustrating example embodiments, but it should be understood that the inventions are not limited to the arrangements and instrumentality shown in the drawings. In the drawings, identical reference numbers identify at least generally similar elements. To facilitate the discussion of any particular element, the most significant digit or digitsAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO of any reference number refers to the Figure in which that element is first introduced. For example, element 103a is first introduced and discussed with reference to Figure 1A.DETAILED DESCRIPTIONI. Overview

[0022] In multi-room audio systems, understanding the acoustic relationships between playback devices and other components is beneficial for enhancing audio experiences, voice control functionality, and any location-aware control functionality. However, traditional methods of device localization often fall short in capturing the acoustic landscape of a household, potentially leading to suboptimal audio rendering and voice control performance.

[0023] The present technology addresses these and other challenges by characterizing the acoustic topology of an environment, such as by determining the acoustic separation between playback devices (or other components) within a media playback system. Unlike conventional spatial mapping techniques that focus solely on physical distances, this approach emphasizes the acoustic relationships between devices. By measuring and analyzing how audible each pair of playback devices are from one another, the system characterizes the acoustic interrelatedness (or lack thereof) between devices, which more accurately represents the sound propagation characteristics of the environment.

[0024] This acoustic topology enables a range of enhanced functionalities, including improved voice command disambiguation, more intuitive '‘play near me” rendering, and flexible home theater arrangements. For instance, when a voice command is detected, the system can use acoustic topology information to determine which device should respond based on acoustic proximity rather than merely physical distance. Similarly, the acoustic topology information allows for dynamic grouping of playback devices that are acoustically close, even if this involve grouping devices that are relatively further apart physically and excluding devices that are relatively close physically but are separated by walls or other acoustic obstacles. As another example, by determining the location of a remote control (e.g., a control device) by using localization signals, turning down the volume on a playback device via the remote control can automatically also turn down the volume on other devices in the same acoustic space. Such acoustic topology' determination may also allow for the automatic generation of playback groups (e.g., automatic generation of rooms, zones, etc.) without requiring active user selection. By providing a more comprehensive understanding of the acoustic relationships between devices, theAttorney Docket No 24-0201-PCTFortem Reference No. SNS.152WO present technology significantly improves the user experience in multi-room audio systems, offering more natural and context-aware interactions with voice control and audio playback functionalities.

[0025] Although many of the examples described herein refer to media playback systems, one skilled in the art will recognize that similar systems and methods can be used in a variety of different systems to locate target devices, predict target devices, and / or train such a predictor, including (but not limited to) security systems, Internet of Things (loT) systems, etc., without departing from the scope of the present disclosure. Further, the techniques described herein may be advantageously employed for device localization and / or acoustic separation in any of a variety' of operating environments including indoor environments, outdoor environments, and mixed indoor-outdoor environments.

[0026] 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 description 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.II. Example Operating Environment

[0027] Figures 1A and IB illustrate an example configuration of a media playback system 100 (or “MPS 100”) in which one or more examples disclosed herein may be implemented. Referring first to Figure 1 A, the MPS 100 as shown is associated with an example home environment having a plurality of rooms and spaces, which may be collectively referred to as a “home environment,” “smart home,” or “environment 101.” The environment 101 comprises a household having several rooms, spaces, and / or playback zones, including a master bathroom 101a, a master bedroom 101b (referred to herein as “Nick’s Room”), a second bedroom 101c, a family room or den 101 d, an office 101 e, a living room 10 If, a dining room 101g, a kitchen lOlh, and an outdoor patio lOli. While certain examples and examples are described below in the context of a home environment, the technologies described herein may be implemented in other ty pes of environments. In some examples, for instance, the MPS 100 can be implemented in one or more commercial settings (e.g.. a restaurant, mall, airport, hotel, a retail or other store), one or more vehicles (e.g.. a sports utility vehicle, bus, car, a ship, a boat, an airplane), multiple environments (e.g., a combination ofAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO home and vehicle environments), and / or another suitable environment where multi-zone audio may be desirable.

[0028] Within these rooms and spaces, the MPS 100 includes one or more computing devices. Referring to Figures 1A and IB together, such computing devices can include playback devices 102 (identified individually as playback devices 102a-102o), network microphone devices 103 (identified individually as “NMDs” 103a-102i), and controller devices 104a and 104b (collectively “controller devices 104’’). Referring to Figure IB, the home environment may include additional and / or other computing devices, including local network devices, such as one or more smart illumination devices 108 (Figure IB), a smart thermostat 110, and a local computing device 105 (Figure 1A). In examples described below, one or more of the various playback devices 102 may be configured as portable playback devices, while others may be configured as stationary playback devices. For example, the headphones 102o (Figure IB) are a portable playback device, while the playback device 102d on the bookcase may be a stationary' device. As another example, the playback device 102c on the Patio may be a battery-powered device, which may allow it to be transported to various areas within the environment 101, and outside of the environment 101, when it is not plugged in to a wall outlet or the like.

[0029] With reference still to Figure I B, the various playback, network microphone, and controller devices 102-104 and / or other network devices of the MPS 100 may be coupled to one another via point-to-point connections and / or over other connections, which may be wired and / or wireless, via a LAN 111 including a network router 109. For example, the playback device 102j in the Den 101 d (Figure 1A), which may be designated as the “Left” device, may have a point-to- point connection with the playback device 102a, winch is also in the Den lOld and may be designated as the “Right” device. In a related example, the Left playback device 102j may communicate with other network devices, such as the playback device 102b. which may be designated as the “Front” device, via a point-to-point connection and / or other connections via the LAN 111.

[0030] As further shown in Figure IB, the MPS 100 may be coupled to one or more remote computing devices 106 via a wide area network (“WAN”) 107. In some examples, each remote computing device 106 may take the form of one or more cloud servers. The remote computing devices 106 may be configured to interact with computing devices in the environment 101 in various ways. For example, the remote computing devices 106 may be configured to facilitateAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO streaming and / or controlling playback of media content, such as audio, in the home environment 101.

[0031] In some implementations, the various playback devices, NMDs, and / or controller devices 102-104 may be communicatively coupled to at least one remote computing device associated with a VAS and at least one remote computing device associated with a media content service (‘ MCS ’). For instance, in the illustrated example of Figure IB, remote computing devices 106a are associated with a VAS 190 and remote computing devices 106b are associated with an MCS 192. Although only a single VAS 190 and a single MCS 192 are shown in the example of Figure IB for purposes of clarity, the MPS 100 may be coupled to multiple, different VASes and / or MCSes. In some implementations, VASes may be operated by one or more of AMAZON, GOOGLE, APPLE, MICROSOFT, SONOS or other voice assistant providers. In some implementations, MCSes may be operated by one or more of SPOTIFY, PANDORA, AMAZON MUSIC, or other media content services.

[0032] As further shown in Figure IB, the remote computing devices 106 further include remote computing device 106c configured to perform certain operations, such as remotely facilitating media playback functions, managing device and system status information, directing communications between the devices of the MPS 100 and one or multiple VASes and / or MCSes, among other operations. In one example, the remote computing devices 106c provide cloud serv ers for one or more SONOS Wireless HiFi Systems.

[0033] In various implementations, one or more of the playback devices 102 may take the form of or include an on-board (e.g., integrated) network microphone device. For example, the playback devices 102a-e include or are otherwise equipped with corresponding NMDs 103a-e, respectively. A playback device that includes or is equipped with an NMD may be referred to herein interchangeably as a playback device or an NMD unless indicated otherwise in the description. In some cases, one or more of the NMDs 103 may be a stand-alone device. For example, the NMDs 103f and 103g may be stand-alone devices. A stand-alone NMD may omit components and / or functionality that is typically included in a playback device, such as a speaker or related electronics. For instance, in such cases, a stand-alone NMD may not produce audio output or may produce limited audio output (e.g., relatively low-quality audio output).

[0034] The various playback and netw ork microphone devices 102 and 103 of the MPS 100 may each be associated with a unique name, which may be assigned to the respective devices by a user, such as during setup of one or more of these devices. For instance, as shown in the illustratedAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO example of Figure IB, a user may assign the name “Bookcase” to playback device 102d because it is physically situated on a bookcase. Similarly, the NMD 103f may be assigned the named “Island” because it is physically situated on an island countertop in the Kitchen lOlh (Figure 1A). Some playback devices may be assigned names according to a zone or room, such as the playback devices 102e, 1021, 102m, and 102n, which are named “Bedroom,” “Dining Room,” “Living Room,” and “Office,” respectively. Further, certain playback devices may have functionally descriptive names. For example, the playback devices 102a and 102b are assigned the names “Right” and “Front,” respectively, because these two devices are configured to provide specific audio channels during media playback in the zone of the Den 1 Old (Figure 1A). The playback device 102c in the Patio may be named portable because it is battery-powered and / or readily transportable to different areas of the environment 101. Other naming conventions are possible.

[0035] As discussed above, an NMD may detect and process sound from its environment, such as sound that includes background noise mixed with speech spoken by a person in the NMD’s vicinity. For example, as sounds are detected by the NMD in the environment, the NMD may process the detected sound to determine if the sound includes speech that contains voice input intended for the NMD and ultimately a particular VAS. For example, the NMD may identify whether speech includes a wake word associated with a particular VAS.

[0036] In the illustrated example of Figure IB, the NMDs 103 are configured to interact with the VAS 190 over a network via the LAN 111 and the router 109. Interactions with the VAS 190 may be initiated, for example, when an NMD identifies in the detected sound a potential wake word. The identification causes a wake-word event, which in turn causes the NMD to begin transmitting detected-sound data to the VAS 190. In some implementations, the various local network devices 102-105 (Figure 1A) and / or remote computing devices 106c of the MPS 100 may exchange various feedback, information, instructions, and / or related data with the remote computing devices associated with the selected VAS. Such exchanges may be related to or independent of transmitted messages containing voice inputs. In some examples, the remote computing device(s) and the media playback system 100 may exchange data via communication paths as described herein and / or using a metadata exchange channel as described in U.S. Application No. 15 / 438,749 filed February 21. 2017, and titled “Voice Control of a Media Playback System.” which is herein incorporated by reference in its entirety.

[0037] Upon receiving the stream of sound data, the VAS 190 determines if there is voice input in the streamed data from the NMD, and if so the VAS 190 will also determine an underlyingAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO intent in the voice input. The VAS 190 may next transmit a response back to the MPS 100, which can include transmitting the response directly to the NMD that caused the wake-word event. The response is typically based on the intent that the VAS 190 determined was present in the voice input. As an example, in response to the VAS 190 receiving a voice input with an utterance to “Play Hey Jude by The Beatles,” the VAS 190 may determine that the underlying intent of the voice input is to initiate playback and further determine that intent of the voice input is to play the particular song “Hey Jude.” After these determinations, the VAS 190 may transmit a command to a particular MCS 192 to retrieve content (i.e.. the song “Hey Jude”), and that MCS 192, in turn, provides (e.g., streams) this content directly to the MPS 100 or indirectly via the VAS 190. In some implementations, the VAS 190 may transmit to the MPS 100 a command that causes the MPS 100 itself to retrieve the content from the MCS 192.

[0038] In certain implementations, NMDs may facilitate arbitration amongst one another when voice input is identified in speech detected by two or more NMDs located within proximity of one another. For example, the NMD-equipped playback device 102d in the environment 101 (Figure 1A) is in relatively close proximity to the NMD-equipped Living Room playback device 102m, and both devices 102d and 102m may at least sometimes detect the same sound. In such cases, this may require arbitration as to which device is ultimately responsible for providing detected- sound data to the remote VAS. Examples of arbitrating between NMDs may be found, for example, in previously referenced U.S. Application No. 15 / 438,749.

[0039] In certain implementations, an NMD may be assigned to. or otherwise associated with, a designated or default playback device that may not include an NMD. For example, the Island NMD 103f in the Kitchen lOlh (Figure 1 A) may be assigned to the Dining Room playback device 1021, which is in relatively close proximity to the Island NMD 103f. In practice, an NMD may direct an assigned playback device to play audio in response to a remote VAS receiving a voice input from the NMD to play the audio, which the NMD might have sent to the VAS in response to a user speaking a command to play a certain song, album, playlist, etc. Additional details regarding assigning NMDs and playback devices as designated or default devices may be found, for example, in previously referenced U.S. Patent Application No. 15 / 438,749.

[0040] Further aspects relating to the different components of the example MPS 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 MPS 100, technologies described herein are not limited to applications within, among other things, the homeAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO environment described above. For instance, the technologies described herein may be useful in other home environment configurations comprising more or fewer of any of the playback, network microphone, and / or controller devices 102-104. For example, the technologies herein may be utilized within an environment having a single playback device 102 and / or a single NMD 103. In some examples of such cases, the LAN 111 (Figure IB) may be eliminated and the single playback device 102 and / or the single NMD 103 may communicate directly with the remote computing devices 106a-d. In some examples, a telecommunication network (e.g., an LTE network, a 5G network, etc.) may communicate with the various playback, network microphone, and / or controller devices 102-104 independent of a LAN. a. Example Playback & Network Microphone Devices

[0041] Figure 2A is a functional block diagram illustrating certain aspects of one of the playback devices 102 of the MPS 100 of Figures 1A and IB. As shown, the playback device 102 includes various components, each of which is discussed in further detail below, and the various components of the playback device 102 may be operably coupled to one another via a system bus, communication network, or some other connection mechanism. In the illustrated example of Figure 2A. the playback device 102 may be referred to as an “NMD-equipped?’ playback device because it includes components that support the functionality of an NMD, such as one of the NMDs 103 shown in Figure 1A.

[0042] As shown, the playback device 102 includes at least one processor 212, which may be a clock-driven computing component configured to process input data according to instructions stored in memory 213. The memory 213 may be a tangible, non- transitory, computer-readable medium configured to store instructions that are executable by the processor 212. For example, the memory 213 may be data storage that can be loaded with software code 214 that is executable by the processor 212 to achieve certain functions.

[0043] In one example, these functions may involve the playback device 102 retrieving audio data from an audio source, which may be another playback device. In another example, the functions may involve the playback device 102 sending audio data, detected-sound data(e.g., corresponding to a voice input), and / or other information to another device on a network via at least one network interface 224. In yet another example, the functions may involve the playback device 102 causing one or more other playback devices to synchronously playback audio with the playback device 102. In yet a further example, the functions may involve the playback device 102 facilitating being paired or otherwise bonded with one or more other playback devices to create a multi-channelAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO audio environment. Numerous other example functions are possible, some of which are discussed below.

[0044] As just mentioned, certain functions may involve the playback device 102 synchronizing playback of audio content with one or more other playback devices. During synchronous playback, a listener may not perceive time-delay differences between playback of the audio content by the synchronized playback devices. U.S. Patent No. 8,234,395 filed on April 4. 2004, and titled “System and method for synchronizing operations among a plurality of independently clocked digital data processing devices,” which is hereby incorporated by reference in its entirety7, provides in more detail some examples for audio playback synchronization among playback devices.

[0045] To facilitate audio playback, the playback device 102 includes audio processing components 216 that are generally configured to process audio prior to the playback device 102 rendering the audio. In this respect, the audio processing components 216 may include one or more digital-to-analog converters (“DAC”), one or more audio preprocessing components, one or more audio enhancement components, one or more digital signal processors (“DSPs”), and so on. In some implementations, one or more of the audio processing components 216 may be a subcomponent of the processor 212. In operation, the audio processing components 216 receive analog and / or digital audio and process and / or otherwise intentionally alter the audio to produce audio signals for playback.

[0046] The produced audio signals may then be provided to one or more audio amplifiers 217 for amplification and playback through one or more speakers 218 operably coupled to the amplifiers 217. The audio amplifiers 217 may include components configured to amplify audio signals to a level for driving one or more of the speakers 218.

[0047] Each of the speakers 218 may include an individual transducer (e.g., a “driver”) or the speakers 218 may include a complete speaker system involving an enclosure with one or more drivers. A particular driver of a speaker 218 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, a transducer may be driven by an individual corresponding audio amplifier of the audio amplifiers 217. In some implementations, a playback device may not include the speakers 218, but instead may include a speaker interface for connecting the playback device to external speakers. In certain examples, a playback device may include neither theAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO speakers 218 nor the audio amplifiers 217, but instead may include an audio interface (not shown) for connecting the playback device to an external audio amplifier or audio-visual receiver.

[0048] In addition to producing audio signals for playback by the playback device 102, the audio processing components 216 may be configured to process audio to be sent to one or more other playback devices, via the network interface 224, for playback. In example scenarios, audio content to be processed and / or played back by the playback device 102 may be received from an external source, such as via an audio line-in interface (e.g., an auto-detecting 3.5mm audio line-in connection) of the playback device 102 (not show n) or via the network interface 224, as described below;

[0049] As shown, the at least one network interface 224, may take the form of one or more wireless interfaces 225 and / or one or more wired interfaces 226. A wireless interface may provide network interface functions for the playback device 102 to wirelessly communicate with other devices (e g., other playback device(s), NMD(s), and / or controller device(s)) in accordance with a communication protocol (e.g., any wireless standard including IEEE 802. I la, 802. 1 lb, 802.11g, 802. 1 In, 802. 1 lac, 802.15, 4G mobile communication standard, and so on). A wired interface may provide network interface functions for the playback device 102 to communicate over a wired connection with other devices in accordance with a communication protocol (e.g., IEEE 802.3). While the network interface 224 shown in Figure 2 A include both wired and wireless interfaces, the playback device 102 may in some implementations include only wireless interface(s) or only wired interface(s).

[0050] In general, the network interface 224 facilitates data flow between the playback device 102 and one or more other devices on a data network. For instance, the playback device 102 may be configured to receive audio content over the data network from one or more other playback devices, network devices within a LAN, and / or audio content sources over a WAN, such as the Internet. In one example, the audio content and other signals transmitted and received by the playback device 102 may be transmitted in the form of digital packet data comprising an Internet Protocol (IP)-based source address and IP-based destination addresses. In such a case, the network interface 224 may be configured to parse the digital packet data such that the data destined for the playback device 102 is properly received and processed by the playback device 102.

[0051] As shown in Figure 2A, the playback device 102 also includes voice processing components 220 that are operably coupled to one or more microphones 222. The microphones 222 are configured to detect sound (i.e., acoustic waves) in the environment of the playback deviceAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO102, which is then provided to the voice processing components 220. More specifically, each microphone 222 is configured to detect sound and convert the sound into a digital or analog signal representative of the detected sound, which can then cause the voice processing component 220 to perform various functions based on the detected sound, as described in greater detail below. In one implementation, the microphones 222 are arranged as an array of microphones (e.g., an array of six microphones). In some implementations, the playback device 102 includes more than six microphones (e.g., eight microphones or twelve microphones) or fewer than six microphones (e.g., four microphones, two microphones, or a single microphones).

[0052] In operation, the voice-processing components 220 are generally configured to detect and process sound received via the microphones 222, identify potential voice input in the detected sound, and extract detected-sound data to enable a VAS, such as the VAS 190 (Figure IB), to process voice input identified in the detected-sound data. The voice processing components 220 may include one or more analog-to-digital converters, an acoustic echo canceller (“AEC”), a spatial processor (e.g., one or more multi-channel Wiener filters, one or more other filters, and / or one or more beam former components), one or more buffers (e.g., one or more circular buffers), one or more wake-word engines, one or more voice extractors, and / or one or more speech processing components (e.g., components configured to recognize a voice of a particular user or a particular set of users associated with a household), among other example voice processing components. In example implementations, the voice processing components 220 may include or otherwise take the form of one or more DSPs or one or more modules of a DSP. In this respect, certain voice processing components 220 may be configured with particular parameters (e.g., gain and / or spectral parameters) that may be modified or otherwise tuned to achieve particular functions. In some implementations, one or more of the voice processing components 220 may be a subcomponent of the processor 212.

[0053] In some implementations, the voice-processing components 220 may detect and store a user’s voice profile, which may be associated with a user account of the MPS 100. For example, voice profiles may be stored as and / or compared to variables stored in a set of command information or data table. The voice profile may include aspects of the tone or frequency of a user’s voice and / or other unique aspects of the user’s voice, such as those described in previously- referenced U.S. Patent Application No. 15 / 438,749.

[0054] As further shown in Figure 2A, the playback device 102 also includes power components 227. The power components 227 include at least an external power source interface 228, whichAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO may be coupled to a power source (not shown) via a power cable or the like that physically connects the playback device 102 to an electrical outlet or some other external power source. Other power components may include, for example, transformers, converters, and like components configured to format electrical power.

[0055] In some implementations, the power components 227 of the playback device 102 may additionally include an internal power source 229 (e.g., one or more batteries) configured to power the playback device 102 without a physical connection to an external power source. When equipped with the internal power source 229, the playback device 102 may operate independent of an external power source. In some such implementations, the external power source interface 228 may be configured to facilitate charging the internal power source 229. As discussed before, a playback device comprising an internal power source may be referred to herein as a “portable playback device.” On the other hand, a playback device that operates using an external power source may be referred to herein as a “stationary playback device,” although such a device may in fact be moved around a home or other environment.

[0056] The playback device 102 further includes a user interface 239 that may facilitate user interactions independent of or in conjunction with user interactions facilitated by one or more of the controller devices 104. In various examples, the user interface 239 includes one or more physical buttons and / or supports graphical interfaces provided on touch sensitive screen(s) and / or surface(s), among other possibilities, for a user to directly provide input. The user interface 239 may further include one or more of lights (e.g., LEDs) and the speakers to provide visual and / or audio feedback to a user.

[0057] As an illustrative example, Figure 2Bshows an example housing 230 of the playback device 102 that includes a user interface in the form of a control area 232 at a top portion 234 of the housing 230. The control area 232 includes buttons 236a-c for controlling audio playback, volume level, and other functions. The control area 232 also includes a button 236d for toggling the microphones 222 to either an on state or an off state.

[0058] As further shown in Figure 2B, the control area 232 is at least partially surrounded by apertures formed in the top portion 234 of the housing 230 through which the microphones 222 (not visible in Figure 2B) receive the sound in the environment of the playback device 102. The microphones 222 may be arranged in various positions along and / or within the top portion 234 or other areas of the housing 230 so as to detect sound from one or more directions relative to the playback device 102.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0059] As mentioned above, the playback device 102 may be constructed as a portable playback device, such as an ultra-portable playback device, that comprises an internal power source. Figure 2C shows an example housing 240 for such a portable playback device. As shown, the housing 240 of the portable playback device includes a user interface in the form of a control area 242 at a top portion 244 of the housing 240. The control area 242 may include a capacitive touch sensor for controlling audio playback, volume level, and other functions. The housing 240 of the portable playback device may be configured to engage with a dock 246 that is connected to an external power source via cable 248 (e.g., a USB cable) coupled to a power adapter 249 (e.g., a power adapter that converts power from a wall outlet to a USB port). The dock 246 may be configured to provide power to the portable playback device to recharge an internal battery. In some embodiments, the dock 246 may comprise a set of one or more conductive contacts (not shown) positioned on the top of the dock 246 that engage with conductive contacts on the bottom of the housing 240 (not shown). In other embodiments, the dock 246 may provide power from the cable 248 to the portable playback device without the use of conductive contacts. For example, the dock 246 may wirelessly charge the portable playback device via one or more inductive coils (e.g., consistent with the QI wireless charging standard) integrated into each of the dock 246 and the portable playback device. Additionally, the dock 246 may comprise one or more mechanisms for communicating with the playback device using, for example, Near Field Communication (NFC) and / or BLUETOOTH communication.

[0060] By way of illustration, SONOS, Inc. presently offers (or has offered) for sale certain playback devices that may implement certain of the examples disclosed herein, including a “PLAY:1,” “PLAY:3,” “PLAY:5,” “PLAYBAR,” “MOVE,” “ROAM,” “CONNECT: AMP,” “PLAYBASE,” “BEAM,” “ARC.” “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 examples disclosed herein. Additionally, it should be understood that a playback device is not limited to the examples illustrated in Figures 2A or 2B or to the SONOS product offerings. For example, a playback device may include, or otherwise take the form of, a wired or wireless headphone set, which may operate as a part of the media playback system 100 via a network interface or the like. 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.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO b. Example Playback Device Configurations

[0061] Figures 3 A-3E show example configurations of playback devices. Referring first to Figure 3 A, in some example instances, a single playback device may belong to a zone. For example, the playback device 102c (Figure 1A) on the Patio may belong to Zone A. In some implementations described below, multiple playback devices may be “bonded"’ to form a “bonded pair,” which together form a single zone. For example, the playback device 102f (Figure 1A) named “Bed 1” in Figure 3 A may be bonded to the playback device 102g (Figure 1 A) named “Bed 2” in Figure 3 A to form Zone B. Bonded playback devices may have different playback responsibilities (e.g., channel responsibilities). In another implementation described below, multiple playback devices may be merged to form a single zone. For example, the playback device 102d named “Bookcase” may be merged with the playback device 102m named “Living Room” to form a single Zone C. The merged playback devices 102d and 102m may not be specifically assigned different playback responsibilities. That is, the merged playback devices 102d and 102m may, aside from playing audio content in synchrony, each play audio content as they would if they were not merged.

[0062] For purposes of control, each zone in the MPS 100 may be represented as a single user interface (“UI”) entity. For example, as displayed by the controller devices 104. Zone A may be provided as a single entity named “Portable,” Zone B may be provided as a single entity named “Stereo,” and Zone C may be provided as a single entity named “Living Room.”

[0063] In various examples, a zone may take on the name of one of the playback devices belonging to the zone. For example, Zone C may take on the name of the Living Room device 102m (as shown). In another example, Zone C may instead take on the name of the Bookcase device 102d. In a further example, Zone C may take on a name that is some combination of the Bookcase device 102d and Living Room device 102m. The name that is chosen may be selected by a user via inputs at a controller device 104. In some examples, a zone may be given a name that is different than the device(s) belonging to the zone. For example, Zone B in Figure 3 A is named “Stereo” but none of the devices in Zone B have this name. In one aspect, Zone B is a single UI entity representing a single device named “Stereo,” composed of constituent devices “Bed 1” and “Bed 2.” In one implementation, the Bed 1 device may be playback device 102f in the master bedroom lOlh (Figure 1 A) and the Bed 2 device may be the playback device 102g also in the master bedroom lOlh (Figure 1 A).

[0064] As noted above, playback devices that are bonded may have different playback responsibilities, such as playback responsibilities for certain audio channels. For example, asAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO shown in Figure 3B, the Bed 1 and Bed 2 devices 102f and 102g may be bonded so as to produce or enhance a stereo effect of audio content. In this example, the Bed 1 playback device 102f may be configured to play a left channel audio component, while the Bed 2 playback device 102g may be configured to play a right channel audio component. In some implementations, such stereo bonding may be referred to as '‘pairing.’’

[0065] Additionally, playback devices that are configured to be bonded may have additional and / or different respective speaker drivers. As shown in Figure 3C, the playback device 102b named “Front’’ may be bonded with the playback device 102k named “SUB.” The Front device 102b may render a range of mid to high frequencies, and the SUB device 102k may render low- frequencies as, for example, a subwoofer. When unbonded, the Front device 102b may be configured to render a full range of frequencies. As another example. Figure 3D shows the Front and SUB devices 102b and 102k further bonded with Right and Left playback devices 102a and 102j , respectively. In some implementations, the Right and Left devices 102a and 102j may form surround or “satellite” channels of a home theater system. The bonded playback devices 102a, 102b, 102j , and 102k may form a single Zone D (Figure 3A).

[0066] In some implementations, playback devices may also be “merged.” In contrast to certain bonded playback devices, playback devices that are merged may not have assigned playback responsibilities but may each render the full range of audio content that each respective playback device is capable of. Nevertheless, merged devices may be represented as a single UI entity (i.e., a zone, as discussed above). For instance, Figure 3E shows the playback devices 102d and 102m in the Living Room merged, which would result in these devices being represented by the single UI entity of Zone C. In one example, the playback devices 102d and 102m may playback audio in synchrony, during which each outputs the full range of audio content that each respective playback device 102d and 102m is capable of rendering.

[0067] In some examples, a stand-alone NMD may be in a zone by itself. For example, the NMD 103h from Figure 1A is named “Closet” and forms Zone I in Figure 3A. An NMD may also be bonded or merged with another device so as to form a zone. For example, the NMD device 103f named '‘Island” may be bonded with the playback device 102i Kitchen, which together form Zone F, which is also named “Kitchen.” Additional details regarding assigning NMDs and playback devices as designated or default devices may be found, for example, in previously referenced U.S. Patent Application No. 15 / 438,749. In some examples, a stand-alone NMD may not be assigned to a zone.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0068] Zones of individual, bonded, and / or merged devices may be arranged to form a set of playback devices that playback audio in synchrony. Such a set of playback devices may be referred to as a “group.” “zone group,” “synchrony group,” or “playback group.” In response to inputs provided via a controller device 104. playback devices may be dynamically grouped and ungrouped to form new or different groups that synchronously play back audio content. For example, referring to Figure 3A, Zone A may be grouped with Zone B to form a zone group that includes the playback devices of the two zones. As another example, Zone A may be grouped with one or more other Zones C-I. The Zones A-I may be grouped and ungrouped in numerous ways. For example, three, four, five, or more (e.g., all) of the Zones A-I may be grouped. When grouped, the zones of individual and / or bonded playback devices may play back audio in synchrony with one another, as described in previously referenced U.S. Patent No. 8,234,395. Grouped and bonded devices are example types of associations between portable and stationary playback devices that may be caused in response to a trigger event, as discussed above and described in greater detail below.

[0069] In various implementations, the zones in an environment may be assigned a particular name, which may be the default name of a zone within a zone group or a combination of the names of the zones within a zone group, such as “Dining Room + Kitchen,” as shown in Figure 3A. In some examples, a zone group may be given a unique name selected by a user, such as “Nick’s Room,” as also shown in Figure 3 A. The name “Nick’s Room” may be a name chosen by a user over a prior name for the zone group, such as the room name “Master Bedroom.”

[0070] Referring back to Figure 2A, certain data may be stored in the memory 213 as one or more state variables that are periodically updated and used to describe the state of a playback zone, the playback device(s), and / or a zone group associated therewith. The memory' 213 may also include the data associated with the state of the other devices of the media playback system 100, which may be 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.

[0071] In some examples, the memory 213 of the playback device 102 may store instances of various variable types associated with the states. Variables instances may be stored with identifiers (e.g., tags) corresponding to ty pe. For example, certain identifiers may be a first type “al” to identify playback device(s) of a zone, a second type “bl” to identify playback device(s) that may be bonded in the zone, and a third type “cl” to identify a zone group to which the zone may belong. As a related example, in Figure 1 A, identifiers associated with the Patio may indicate thatAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO the Patio is the only playback device of a particular zone and not in a zone group. Identifiers associated with the Living Room may indicate that the Living Room is not grouped with other zones but includes bonded playback devices 102a, 102b, 102j, and 102k. Identifiers associated with the Dining Room may indicate that the Dining Room is part of Dining Room + Kitchen group and that devices 103f and 102i are bonded. Identifiers associated with the Kitchen may indicate the same or similar information by virtue of the Kitchen being part of the Dining Room + Kitchen zone group. Other example zone variables and identifiers are described below'.

[0072] In yet another example, the MPS 100 may include variables or identifiers representing other associations of zones and zone groups, such as identifiers associated with Areas, as shown in Figure 3 A. An Area may involve a cluster of zone groups and / or zones not within a zone group. For instance, Figure 3A shows a first area named '‘First Area” and a second area named '‘Second Area.” The First Area includes zones and zone groups of the Patio, Den, Dining Room, Kitchen, and Bathroom. The Second Area includes zones and zone groups of the Bathroom, Nick's Room, Bedroom, and Living Room. In one aspect, an Area may be used to invoke a cluster of zone groups and / or zones that share one or more zones and / or zone groups of another cluster. In this respect, such an Area differs from a zone group, which does not share a zone with another zone group. Further examples of techniques for implementing Areas may be found, for example, in U.S. Application No. 15 / 682,506 filed August 21, 2017 and titled “Room Association Based on Name,” and U.S. Patent No. 8,483.853 filed September 11. 2007, and titled “Controlling and manipulating groupings in a multi-zone media system.” Each of these applications is incorporated herein by reference in its entirety7. In some examples, the MPS 100 may not implement Areas, in which case the system may not store variables associated with Areas.

[0073] The memory7213 may be further configured to store other data. Such data may pertain to audio sources accessible by the playback device 102 or a playback queue that the playback device (or some other playback device(s)) may be associated with. In examples described below, the memory 213 is configured to store a set of command data for selecting a particular VAS when processing voice inputs.

[0074] During operation, one or more playback zones in the environment of Figure 1 A may each be playing different audio content. For instance, the user may be grilling in the Patio zone and listening to hip hop music being played by the playback device 102c, while another user may be preparing food in the Kitchen zone and listening to classical music being played by the playback device 102i. In another example, a playback zone may play' the same audio content in synchronyAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO with another playback zone. For instance, the user may be in the Office zone where the playback device 102n is playing the same hip-hop music that is being playing by playback device 102c in the Patio zone. In such a case, playback devices 102c and 102n may be playing the hip-hop 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. Patent No. 8,234,395.

[0075] As suggested above, the zone configurations of the MPS 100 may be dynamically modified. As such, the MPS 100 may support numerous configurations. For example, if a user physically moves one or more playback devices to or from a zone, the MPS 100 may be reconfigured to accommodate the change(s). For instance, if the user physically moves the playback device 102c from the Patio zone to the Office zone, the Office zone may now include both the playback devices 102c and 102n. In some cases, the user may pair or group the moved playback device 102c with the Office zone and / or rename the players in the Office zone using, for example, one of the controller devices 104 and / or voice input. As another example, if one or more playback devices 102 are moved to a particular space in the home environment that is not already a playback zone, the moved playback device(s) may be renamed or associated with a playback zone for the particular space.

[0076] Further, different playback zones of the MPS 100 may be dynamically combined into zone groups or split up into individual playback zones. For example, the Dining Room zone and the Kitchen zone may be combined into a zone group for a dinner party such that playback devices 102i and 1021 may render audio content in synchrony. As another example, bonded playback devices in the Den zone may be split into (i) a television zone and (ii) a separate listening zone. The television zone may include the Front playback device 102b. The listening zone may include the Right, Left, and SUB playback devices 102a, 102j, and 102k, which may be grouped, paired, or merged, as described above. Splitting the Den zone in such a manner may allow one user to listen to music in the listening zone in one area of the living room space, and another user to watch the television in another area of the living room space. In a related example, a user may utilize either of the NMD 103a or 103b (Figure IB) to control the Den zone before it is separated into the television zone and the listening zone. Once separated, the listening zone may be controlled, for example, by a user in the vicinity of the NMD 103a, and the television zone may be controlled,Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO for example, by a user in the vicinity of the NMD 103b. As described above, however, any of the NMDs 103 may be configured to control the various playback and other devices of the MPS 100. c. Example Controller Devices

[0077] Figure 4A is a functional block diagram illustrating certain aspects of a selected one of the controller devices 104 of the MPS 100 of Figure 1 A. Such controller devices may also be referred to herein as a ‘‘control device” or “controller.” The controller device shown in Figure 4A may include components that are generally similar to certain components of the network devices described above, such as a processor 412, memory 413 storing program software 414, at least one network interface 424, and one or more microphones 422. In one example, a controller device may be a dedicated controller for the MPS 100. In another example, a controller device 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™).

[0078] The memory 413 of the controller device 104 may be configured to store controller application software and other data associated with the MPS 100 and / or a user of the system 100. The memory 413 may be loaded with instructions in software 414 that are executable by the processor 412 to achieve certain functions, such as facilitating user access, control, and / or configuration of the MPS 100. The controller device 104 is configured to communicate with other network devices via the network interface 424, which may take the form of a wireless interface, as described above.

[0079] In one example, system information (e.g., such as a state variable) may be communicated between the controller device 104 and other devices via the network interface 424. For instance, the controller device 104 may receive playback zone and zone group configurations in the MPS 100 from a playback device, an NMD, or another network device. Likewise, the controller device 104 may transmit such system information to a playback device or another network device via the network interface 424. In some cases, the other netw ork device may be another controller device.

[0080] The controller device 104 may also communicate playback device control commands, such as volume control and audio playback control, to a playback device via the netw ork interface 424. As suggested above, changes to configurations of the MPS 100 may also be performed by a user using the controller device 104. 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.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO forming a bonded or merged player, separating one or more playback devices from a bonded or merged player, among others.

[0081] As shown in Figure 4A, the controller device 104 also includes a user interface 440 that is generally configured to facilitate user access and control of the MPS 100. The user interface 440 may include a touch-screen display or other physical interface configured to provide various graphical controller interfaces, such as the controller interfaces 440a and 440b shown in Figures 4B and 4C. Referring to Figures 4B and 4C together, the controller interfaces 440a and 440b includes a playback control region 442, a playback zone region 443, a playback status region 444, a playback queue region 446, and a sources region 448. The user interface as shown is just one example of an interface that may be provided on a network device, such as the controller device shown in Figure 4A, and accessed by users to control a media playback system, such as the MPS 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.

[0082] The playback control region 442 (Figure 4B) may include selectable icons (e.g.. by way of touch or by using a cursor) that, when selected, 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, etc. The playback control region 442 may also include selectable icons that, when selected, modify equalization settings and / or playback volume, among other possibilities.

[0083] The playback zone region 443 (Figure 4C) may include representations of playback zones within the MPS 100. The playback zones regions 443 may also include a representation of zone groups, such as the Dining Room + Kitchen zone group, as shown. In some examples, the graphical representations of playback zones may be selectable to bring up additional selectable icons to manage or configure the playback zones in the MPS 100, such as a creation of bonded zones, creation of zone groups, separation of zone groups, and renaming of zone groups, among other possibilities.

[0084] 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 MPS 100 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 inAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO 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 are also possible. The representations of playback zones in the playback zone region 443 (Figure 4C) may be dynamically updated as playback zone or zone group configurations are modified.

[0085] The playback status region 444 (Figure 4B) 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 a controller interface, such as within the playback zone region 443 and / or the playback status region 444. The graphical representations may include track title, artist name, album name, album year, track length, and / or other relevant information that may be useful for the user to know when controlling the MPS 100 via a controller interface.

[0086] The playback queue region 446 may include graphical representations of audio content in a playback queue associated with the selected playback zone or zone group. In some examples, each playback zone or zone group may be associated with a playback queue comprising 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, which may then be played back by the playback device.

[0087] 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 streamed 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 example, 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.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0088] 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 may 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 may 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.

[0089] With reference still to Figures 4B and 4C, the graphical representations of audio content in the playback queue region 446 (Figure 4B) may include track titles, artist names, track lengths, and / or 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. Playback of such a playback queue may involve one or more playback devices playing back media items of the queue, perhaps in sequential or random order.

[0090] The sources region 448 may include graphical representations of selectable audio content sources and / or selectable voice assistants associated with a corresponding VAS. The VASes may be selectively assigned. In some examples, multiple VASes, such as AMAZON’S Alexa,Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WOMICROSOFT’S Cortana, etc., may be invokable by the same NMD. In some examples, a user may assign a VAS exclusively to one or more NMDs. For example, a user may assign a first VAS to one or both of the NMDs 102a and 102b in the Living Room shown in Figure 1 A, and a second VAS to the NMD 103f in the Kitchen. Other examples are possible. d. Example Audio Content Sources

[0091] The audio sources in the sources region 448 may be audio content sources from which audio content may be retrieved and played by the selected playback zone or zone group. 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., via 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. As described in greater detail below, in some examples, audio content may be provided by one or more media content services.

[0092] Example audio content sources may include a memory of one or more playback devices in a media playback system such as the MPS 100 of Figure 1, local music libraries on one or more network devices (e.g., a controller device, a network-enabled personal computer, or a networked- attached storage (“NAS”)), streaming audio services providing audio content via the Internet (e.g., cloud-based music services), or audio sources connected to the media playback system via a line- in input connection on a playback device or network device, among other possibilities.

[0093] In some examples, audio content sources may be added or removed from a media playback system such as the MPS 100 of Figure 1A. 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 / directories shared over a network accessible by playback devices in the media playback system and generating or updating an audio content database comprising 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.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO e. Example Network Microphone Devices

[0094] Figure 5 is a functional block diagram showing an NMD 503 configured in accordance with examples of the disclosure. The NMD 503 includes a voice activity detector 550, voice capture components (“VCC”, or collectively “voice processor 560”), a wake-word engine 570, and at least one voice extractor 572, each of which is operably coupled to the voice processor 560. The NMD 503 further includes the microphones 222 and the at least one network interface 224 described above and may also include other components, such as audio amplifiers, interface, etc., which are not show n in Figure 5 for purposes of clarity.

[0095] The microphones 222 of the NMD 503 are configured to provide detected sound, &>, from the environment of the NMD 503 to the voice activity' detector 550. The detected sound SD may take the form of one or more analog or digital signals. In example implementations, the detected sound SD may be composed of a plurality signals associated with respective channels 562 that are fed to the voice processor 560.

[0096] Each channel 562 may correspond to a particular microphone 222. For example, an NMD having six microphones may have six corresponding channels. Each channel of the detected sound SD may bear certain similarities to the other channels but may differ in certain regards, which may be due to the position of the given channeFs corresponding microphone relative to the microphones of other channels. For example, one or more of the channels of the detected sound SD may have a greater signal to noise ratio (“SNR”) of speech to background noise than other channels.

[0097] In operation, the voice activity detector 550 can process the detected sound SD to determine whether speech is present. If voice activity is detected, the detected sound SD can be passed to the VCC 560 for additional downstream processing. While in some examples the detected sound SD is passed to the VCC 560 without any processing via the voice activity detector 550, in various examples the voice activity detector 550 may perform certain processing functions such that the input to the voice activity detector 550 is not identical to the output SD provided to the VCC 560. For example, the voice activity detector 550 may buffer and / or time-delay the signal, may perform channel selection, or any other suitable pre-processing steps.

[0098] If, voice activity is not identified in the detected sound SD via the voice activity detector 550, then the further processing steps may be forgone. For example, the sound data may not be passed to the VCC 560 and downstream components. Additionally or alternatively, theAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO downstream components can be configured to forgo processing the incoming sound data &>, such as by the use of bypass tags or other techniques. In some examples, the downstream components (e.g., VCC 560, wake-word engine 570, voice extractor 572, network interface 224) can remain in a standby, disabled, or low-power state until voice activity is detected via the voice activity detector 550, at which point some or all of these downstream components can transition to a higher-power or fully operational state. When transitioning from the low-power, standby, or disabled stage to a fully operational stage, any number of components may be turned on, supplied power or additional power, taken out of standby or sleep stage, or otherwise activated in such a way that the enabled component(s) are allowed to draw more power than they could when disabled. With this arrangement, the NMD 503 can assume a relatively low-power stage while monitoring for speech activity7via the voice activity detector 550. Unless and until the voice activity detector 550 identifies voice activity, the NMD 503 may remain in the low-power stage. In some examples, after transitioning to the higher-power or fully operational stage, the NMD 503 may revert to the low-power or standby stage once voice input is no longer detected via the voice activity7detector 550, after a VAS interaction is determined to be concluded, and / or once a given period of time has elapsed.

[0099] In various examples, the voice activity' detector 550 can perform a first algorithm for identifying speech in the sound data SD detected via the microphone(s) 222. The algorithm can include any suitable algorithm for discriminating between speech and non-speech sound data. In some examples, the algorithm can include extracting certain acoustic features from the sound data, such as energy-based features (e.g., signal-to-noise ratio), periodicity' (e.g., speech signals tend to be more periodic than background noises), speech signal dynamics (e.g., analyzing the variance of power envelopes), or others. One or more such acoustic features can then be analyzed using statistical models or other discriminators to detect voice activity in the sound data. Example classifiers include Gaussian mixture models, Laplacian models, or other classifiers that discriminate between speech and non-speech sound data. Additional examples include using neural network-based approaches. As well as energy, other features including entropy, pitch, or zero-crossing rate can be used as input to the classifier. Many approaches can be implemented directly in the time-domain or alternatively in the frequency-domain by applying a filter bank to the microphone input signals. For example, a short-time Fourier transform (STFT) enables SD and the associated features to be efficiently split into multiple frequency bands each of which can be processed independently. In some examples, detecting speech in the sound data via the voice activity7detector 550 consumes less power and / or computational resources (e.g., as measured byAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO average CPU clock rate or millions of instructions per second (MIPS) values) than one or more of the downstream processes such as spatial processing, acoustic echo cancellation, wake-word detection, or any other dow nstream signal processing steps. For example, the amount of energy required to power a processing unit is directly related to the clock rate or MIPS, thus by reducing the average MIPS it is possible to also reduce average power consumption. In some examples, the VAD 550 process can run on a Digital Signal Processor (DSP) co-processing unit or Low Powder Island (LPI), enabling the main CPU to sleep or transition to a low-power state at times when voice activity’ is not detected.

[0100] As further shown in Figure 5. the voice processor 560 includes an AEC 564, a spatial processor 566. and one or more buffers 568. In operation, the AEC 564 receives the detected sound SD and filters or otherwise processes the sound to suppress echoes and / or to otherwise improve the quality of the detected sound SD. That processed sound may then be passed to the spatial processor 566.

[0101] The spatial processor 566 is typically configured to analyze the detected sound SD and identify certain characteristics, such as a sound’s amplitude (e.g., decibel level), frequencyspectrum, directionality, etc. In one respect, the spatial processor 566 may help filter or suppress ambient noise in the detected sound SD from potential user speech based on similarities and differences in the constituent channels 562 of the detected sound SD, as discussed above. As one possibility, the spatial processor 566 may monitor metrics that distinguish speech from other sounds. Such metrics can include, for example, energy within the speech band relative to background noise and entropy within the speech band - a measure of spectral structure - which is ty pically low er in speech than in most common background noise. In some implementations, the spatial processor 566 may be configured to determine a speech presence probability, examples of such functionality are disclosed in U.S. Patent Application No. 15 / 984,073, filed May 18. 2018, titled "‘Linear Filtering for Noise-Suppressed Speech Detection.” and U.S. Patent Application No. 16 / 147,710, filed September 29, 2018, and titled “Linear Filtering for Noise-Suppressed Speech Detection via Multiple Network Microphone Devices,” each of which is incorporated herein by reference in its entirety.

[0102] The wake-word engine 570 is configured to monitor and analyze received audio to determine if any wake words are present in the audio. The wake-word engine 570 may analyze the received audio using a wake word detection algorithm. If the wake-word engine 570 detects a wake word, a network microphone device may process voice input contained in the receivedAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO audio. Example wake-word detection algorithms accept audio as input and provide an indication of whether a wake word is present in the audio. Many first- and third-party wake word detection algorithms are known and commercially available. For instance, operators of a voice service may make their algorithm available for use in third-party’ devices. Alternatively, an algorithm may be trained to detect certain wake-words.

[0103] In some examples, the wake-word engine 570 runs multiple wake word detection algorithms on the received audio simultaneously (or substantially simultaneously). As noted above, different voice services (e.g. AMAZON'S Alexa®, APPLE'S Siri®, MICROSOFT'S Cortana®, GOOGLE'S Assistant, etc.) each use a different wake word for invoking their respective voice service. To support multiple services, the wake-word engine 570 may run the received audio through the wake word detection algorithm for each supported voice service in parallel. In such examples, the network microphone device 103 may include VAS selector components 574 configured to pass voice input to the appropriate voice assistant service. In other examples, the VAS selector components 574 may be omitted. In some examples, individual NMDs 103 of the MPS 100 may be configured to run different wake word detection algorithms associated with particular VASes. For example, the NMDs of playback devices 102a and 102b of the Living Room may be associated with AMAZON’S ALEXA®, and be configured to run a corresponding wake word detection algorithm (e.g.. configured to detect the wake word “Alexa"’ or other associated wake word), while the NMD of playback device 102f in the Kitchen may be associated with GOOGLE’s Assistant, and be configured to run a corresponding wake word detection algorithm (e.g., configured to detect the wake word “OK, Google” or other associated wake w ord).

[0104] In some examples, a network microphone device may include speech processing components configured to further facilitate voice processing, such as by performing voice recognition trained to recognize a particular user or a particular set of users associated with a household. Voice recognition software may implement voice-processing algorithms that are tuned to specific voice profile(s).

[0105] In operation, the one or more buffers 568 - one or more of which may be part of or separate from the memory’ 213 (Figure 2A) - capture data corresponding to the detected sound SD. MoreAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO specifically, the one or more buffers 568 capture detected-sound data that was processed by the upstream voice activity detector 550, AEC 564, and spatial processor 566.

[0106] In general, the detected-sound data form a digital representation (i.e., sound-data stream), SDS, of the sound detected by the microphones 222. In practice, the sound-data stream SDS may take a variety of forms. As one possibility, the sound-data stream SDS may be composed of frames, each of which may include one or more sound samples. The frames may be streamed (i.e.. read out) from the one or more buffers 568 for further processing by downstream components, such as the wake-word engine 570 and the voice extractor 572 of the NMD 503.

[0107] In some implementations, at least one buffer 568 captures detected-sound data utilizing a sliding window approach in which a given amount (i.e., a given window) of the most recently captured detected-sound data is retained in the at least one buffer 568 while older detected-sound data are overwritten when they fall outside of the window. For example, at least one buffer 568 may temporarily retain 20 frames of a sound specimen at given time, discard the oldest frame after an expiration time, and then capture a new7frame, which is added to the 19 prior frames of the sound specimen.

[0108] In practice, when the sound-data stream SDS is composed of frames, the frames may take a variety of forms having a variety of characteristics. As one possibility, the frames may take the form of audio frames that have a certain resolution (e.g., 16 bits of resolution), which may be based on a sampling rate (e.g., 44,100 Hz). Additionally, or alternatively, the frames may include information corresponding to a given sound specimen that the frames define, such as metadata that indicates frequency response, power input level, signal-to-noise ratio, microphone channel identification, and / or other information of the given sound specimen, among other examples. Thus, in some examples, a frame may include a portion of sound (e.g., one or more samples of a given sound specimen) and metadata regarding the portion of sound. In other examples, a frame may only include a portion of sound (e.g., one or more samples of a given sound specimen) or metadata regarding a portion of sound.

[0109] The voice processor 560 also includes at least one lookback buffer 569, which may be part of or separate from the memory 213 (Figure 2A). In operation, the lookback buffer 569 can store sound metadata that is processed based on the detected-sound data SD received from the microphones 222. As noted above, the microphones 222 can include a plurality of microphones arranged in an array. The sound metadata can include, for example: (1) frequency response data for individual microphones of the array, (2) an echo return loss enhancement measure (i.e., aAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO measure of the effectiveness of the acoustic echo canceller (AEC) for each microphone), (3) a voice direction measure; (4) arbitration statistics (e.g., signal and noise estimates for the spatial processing streams associated with different microphones); and / or (5) speech spectral data (i.e., frequency response evaluated on processed audio output after acoustic echo cancellation and spatial processing have been performed). Other sound metadata may also be used to identify and / or classify noise in the detected-sound data SD. In at least some examples, the sound metadata may be transmitted separately from the sound-data stream SDS, as reflected in the arrow extending from the lookback buffer 569 to the network interface 224. For example, the sound metadata may be transmitted from the lookback buffer 569 to one or more remote computing devices separate from the VAS which receives the sound-data stream SDS.

[0110] In any case, components of the NMD 503 downstream of the voice processor 560 may process the sound-data stream SDS. For instance, the wake-word engine 570 can be configured to apply one or more identification algorithms to the sound-data stream SDS (e.g., streamed sound frames) to spot potential wake words in the detected-sound SD. When the wake-word engine 570 spots a potential wake word, the wake-word engine 570 can provide an indication of a “wakeword event” (also referred to as a “wake-word trigger”) to the voice extractor 572 in the form of signal Sw.[OHl] In response to the wake-word event (e.g., in response to a signal Sir from the wake-word engine 570 indicating the wake-word event), the voice extractor 572 is configured to receive and format (e.g., packetize) the sound-data stream SDS. For instance, the voice extractor 572 packetizes the frames of the sound-data stream SDS into messages. The voice extractor 572 transmits or streams these messages. Mr. that may contain voice input in real time or near real time to a remote VAS, such as the VAS 190 (Figure IB), via the network interface 224.

[0112] The VAS is configured to process the sound-data stream SDS contained in the messages Mv sent from the NMD 503. More specifically, the VAS is configured to identify voice input based on the sound-data stream SDS. Referring to Figure 6A, a voice input 680 may include a wake-word portion 680a and an utterance portion 680b. The w ake-word portion 680a corresponds to detected sound that caused the wake-word event. For instance, the w ake-w ord portion 680a corresponds to detected sound that caused the wake-word engine 570 to provide an indication of a w ake-word event to the voice extractor 572. The utterance portion 680b corresponds to detected sound that potentially comprises a user request following the w ake-word portion 680a.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0113] As an illustrative example, Figure 6B shows an example first sound specimen. In this example, the sound specimen corresponds to the sound-data stream SDS (e.g., one or more audio frames) associated with the spotted wake word 680a of Figure 6A. As illustrated, the example first sound specimen comprises sound detected in the playback device 102i’s environment (i) immediately before a wake word was spoken, which may be referred to as a pre-roll portion (between times to and ti), (ii) while the wake word was spoken, which may be referred to as a wake-meter portion (between times ti and t2), and / or (iii) after the wake word was spoken, which may be referred to as a post-roll portion (between times t2 and t.fi. Other sound specimens are also possible.

[0114] Typically, the VAS may first process the wake-word portion 680a within the sound-data stream &s to verily the presence of the wake word. In some instances, the VAS may determine that the wake-word portion 680a comprises a false wake word (e.g., the word "‘Election” when the word “Alexa” is the target wake word). In such an occurrence, the VAS may send a response to the NMD 503 (Figure 5) with an indication for the NMD 503 to cease extraction of sound data, which may cause the voice extractor 572 to cease further streaming of the detected-sound data to the VAS. The wake-word engine 570 may resume or continue monitoring sound specimens until another potential wake word, leading to another wake-word event. In some implementations, the VAS may not process or receive the wake-word portion 680a but instead processes only the utterance portion 680b.

[0115] In any case, the VAS processes the utterance portion 680b to identify the presence of any words in the detected-sound data and to determine an underlying intent from these words. The words may correspond to a certain command and certain keywords 684 (identified individually in Figure 6A as a first keyword 684a and a second keyword 684b). A keyword may be, for example, a word in the voice input 680 identifying a particular device or group in the MPS 100. For instance, in the illustrated example, the keywords 684 may be one or more words identifying one or more zones in which the music is to be played, such as the Living Room and the Dining Room (Figure 1A).

[0116] To determine the intent of the words, the VAS is typically in communication with one or more databases associated with the VAS (not shown) and / or one or more databases (not shown) of the MPS 100. Such databases may store various user data, analytics, catalogs, and other information for natural language processing and / or other processing. In some implementations, such databases may be updated for adaptive learning and feedback for a neural network based onAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO voice-input processing. In some cases, the utterance portion 680b may include additional information, such as detected pauses (e.g., periods of non-speech) between words spoken by a user, as shown in Figure 6A. The pauses may demarcate the locations of separate commands, keywords, or other information spoke by the user within the utterance portion 680b.

[0117] Based on certain command criteria, the VAS may take actions as a result of identifying one or more commands in the voice input, such as the command 682. Command criteria may be based on the inclusion of certain keywords within the voice input, among other possibilities. Additionally, or alternatively, command criteria for commands may involve identification of one or more control-state and / or zone-state variables in conjunction with identification of one or more particular commands. Control-state variables may include, for example, indicators identifying a level of volume, a queue associated with one or more devices, and playback state, such as whether devices are playing a queue, paused, etc. Zone-state variables may include, for example, indicators identifying which, if any, zone players are grouped.

[0118] After processing the voice input, the VAS may send a response to the MPS 100 with an instruction to perform one or more actions based on an intent it determined from the voice input. For example, based on the voice input, the VAS may direct the MPS 100 to initiate playback on one or more of the playback devices 102, control one or more of these devices (e.g., raise / lower volume, group / ungroup devices, etc.), turn on / off certain smart devices, among other actions. After receiving the response from the VAS, the wake-word engine 570 the NMD 503 may resume or continue to monitor the sound-data stream SDS until it spots another potential wake-word, as discussed above.

[0119] Referring back to Figure 5, in multi-VAS implementations, the NMD 503 may include a VAS selector 574 (shown in dashed lines) that is generally configured to direct the voice extractor’s extraction and transmission of the sound-data stream SDS to the appropriate VAS when a given wake-word is identified by a particular wake-word engine, such as the first wake-word engine 570a, the second wake-word engine 570b, or the additional wake-word engine 571. In such implementations, the NMD 503 may include multiple, different wake- word engines and / or voice extractors, each supported by a particular VAS. Similar to the discussion above, each wake-word engine may be configured to receive as input the sound-data stream SDS from the one or more buffers 568 and apply identification algorithms to cause a wake-word trigger for the appropriate VAS. Thus, as one example, the first wake-word engine 570a may be configured to identify the wake word “Alexa” and cause the NMD 503 to invoke the AMAZON VAS when “Alexa” isAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO spotted. As another example, the second wake-word engine 570b may be configured to identify the wake word “Ok, Google” and cause the NMD 503 to invoke the GOOGLE VAS when “Ok, Google” is spotted. In single-VAS implementations, the VAS selector 574 may be omitted.

[0120] In additional or alternative implementations, the NMD 503 may include other voice-input identification engines 571 (shown in dashed lines) that enable the NMD 503 to operate without the assistance of a remote VAS. As an example, such an engine may identify in detected sound certain commands (e.g., “play,” “pause,” “turn on,” etc.) and / or certain keywords or phrases, such as the unique name assigned to a given playback device (e.g., “Bookcase,” “Patio,” “Office,” etc.). In response to identifying one or more of these commands, keywords, and / or phrases, the NMD 503 may communicate a signal (not shown in Figure 5) that causes the audio processing components 216 (Figure 2A) to perform one or more actions. For instance, when a user says “Hey Sonos, stop the music in the office,” the NMD 503 may communicate a signal to the office playback device 102n, either directly, or indirectly via one or more other devices of the MPS 100, which causes the office device 102n to stop audio playback. Reducing or eliminating the need for assistance from a remote VAS may reduce latency that might otherwise occur when processing voice input remotely. In some cases, the identification algorithms employed may be configured to identify commands that are spoken without a preceding wake word. For instance, in the example above, the NMD 503 may employ an identification algorithm that triggers an event to stop the music in the office without the user first saying “Hey Sonos” or another wake word.III. Characterizing Acoustic Topology of Media Playback Systems

[0121] As noted previously, there are many instances in which identifying and maintaining information that characterizes the acoustic topology of a media playback system can provide distinct benefits. Several examples of estimating, determining, or otherwise characterizing the acoustic topology of media playback system components are described below. In various embodiments, the number, arrangement, and configuration of the various devices within the media playback system can vary. Additionally or alternatively, the measurement modalities employed by the various devices can vary. In at least some instances, the devices within the environment can be configured to utilize two or more measurement modalities (e.g., sound-based acoustic separation determination in conjunction with ultra-wideband localization).

[0122] As used herein, “acoustic topology” refers to a characterization of the acoustic relationships between multiple playback devices within an environment. The acoustic topology represents how sound propagates between devices, taking into account factors such as physicalAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO obstructions, room layouts, and acoustic properties of the environment. This characterization is based on measurements of acoustic separation parameters between pairs or larger groups of devices, which may include factors such as signal attenuation, time-of-flight, and frequency response characteristics. The acoustic topology’ may be represented as a graph or map where nodes correspond to playback devices and edges represent the acoustic relationships between them. As described in more detail elsewhere herein, this acoustic topology' information can be used to optimize audio playback, device grouping, and voice control functionalities in a media playback system by providing a more nuanced understanding of the acoustic landscape than physical distance alone. a. Example Architecture for Characterizing Acoustic Topology

[0123] Systems and methods described herein can be used to characterize the acoustic topology’ of devices in networked device systems. In various examples, the processes descnbed herein can be distributed across multiple devices (e.g., portable devices, stationary devices, remote devices, etc.). In some instances, an orchestrator device is designated to coordinate and schedule measurement sessions, and an acoustic relationship analyzer device is designated to collect and store signal information from the session participant devices. Orchestrator and acoustic relationship analyzer devices can be selected from the available devices of an MPS based on one or more of several factors, including (but not limited to) frequency of use or device specifications (e.g., number of processor cores, processor clock speed, processor cache size, non-volatile memory size, volatile memory size, etc.). For example, a particular playback device can be selected as an orchestrator or acoustic relationship analyzer device based on how long the processor has been idle, so as not to interfere with the operation of any’ other devices during playback (e.g., selecting a speaker sitting in a guest bedroom that is used infrequently). In certain embodiments, orchestrator and / or acoustic relationship analyzer devices can include a portable device that is being acoustically analyzed.

[0124] Figure 7 is a functional block diagram of components for characterizing the acoustic topology of a media playback system. As illustrated, the system includes an orchestrator device 750, an acoustic relationship analyzer device 760, and first and second session participant devices 770a and 770b (collectively “participant devices 770'’). Each of these devices can communicate with one another via one or more network(s) 107 (e.g., a LAN or WLAN). Each of these devices can be or include any one of the devices previously described herein (e.g.. a playback device, network microphone device, controller device) or any other suitable device. Together, theseAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO devices can be used to obtain information regarding the acoustic topology of the environment based at least in part on signals obtained via the participant devices 770. For instance, the devices can be used to construct a topological map, characterize the acoustic topology, estimate the acoustic topology, or otherwise obtain acoustic topology information that can be used to control or influence playback device operations.

[0125] The orchestrator 750 can include some or all of the features of the various devices described above (e.g., playback device 102, network microphone device 103 or 503, controller device 104, etc.). As illustrated, the orchestrator 750 can include orchestration components 708 in addition to one or more processor(s) 702, a network interface 704, and a memory 706. The orchestrator 750 can optionally include playback components 714 (e.g., audio transducer, amplifier, etc.) and / or acoustic measurement components 712. In operation, the orchestrator 750 may be responsible for coordinating and scheduling sessions in which the various participant devices 770 transmit and receive signals. This coordination can be effected via the orchestration components 708. The orchestrator 750 may maintain a list of network devices within the environment, optionally with state information for the various devices. The orchestrator may use this list to generate instructions for sessions, including scheduling particular sessions in a desired order. In some cases, the acoustic measurement sessions can be performed sequentially, while in other cases they can be performed at least partially in parallel, particularly if there are known discrete clusters of devices do not overlap (e.g.. upstairs and downstairs groups).

[0126] The acoustic relationship analyzer 760 can likewise include some or all of the features of the various devices described above (e.g., playback device 102, network microphone device 103 or 503, controller device 104, etc.). As shown in Figure 7, the acoustic relationship analyzer 760 can include topology7components 708 in addition to one or more processor(s) 702, a network interface 704, and a memory7706. The acoustic relationship analyzer 760 can optionally include playback components 714 (e.g., audio transducer, amplifier, etc.) and / or measurement components 712. In operation, the acoustic relationship analyzer 760 can receive measurement parameters from the participant devices 770 (e.g., relative or absolute measurements between various device pairs). Based on these measurement parameters, the acoustic relationship analyzer 760 can construct an acoustic topology using the topology components 709. The acoustic topologyinformation can be maintained and updated periodically according to a schedule or in response to various update events as instructed by the orchestrator 750. In some examples, the resulting acoustic topology7information can be transmitted to the other devices of the system such that eachAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO device maintains a local copy of the acoustic topology information that is updated when a new version is received from the acoustic relationship analyzer 760. In alternative configurations, the acoustic relationship analyzer 760 can maintain the acoustic topology information which is then used to change a state or otherwise modify’ operation of other devices within the environment.

[0127] Session participant devices 770 can also include some or all of the features of the various devices described above (e.g., playback device 102, network microphone device 103 or 503, controller device 104, etc ). As shown in Figure 7, the participant devices 770 can each include measurement components 712 in addition to one or more processor(s) 702, a network interface 704, and a memory 706. The participant devices 770 can optionally also include playback components 714 (e.g., audio transducer, amplifier, etc.).

[0128] The measurement components 712 can take the form of hardware and software that enable transmission and / or reception of acoustic signals, as well as processing the detected signals to obtain acoustic measurement parameters. In some examples, the participant devices 770 can transmit “raw” or unprocessed acoustic data to the acoustic relationship analyzer 760 for processing and construction. In other cases, the participant devices 770 may perform some processing of the measurements to obtain, e.g.. inter-device acoustic attenuation or other information which is then transmitted to the acoustic relationship analyzer device 760. In various examples, the signals can take the form of sound signals (e.g., audible or ultrasonic sound signals) or any other suitable signals. The measurement components 712 can, in various examples, include transmitters (e.g., audio transducers) and / or receivers (e.g., microphones). In at least some instances, each participant device includes both transmitter and receiver components, such that each device may, in turn, operate as a session manager (e.g., transmitter) and a session managee (e.g., receiver).

[0129] In operation, for a particular measurement session, one participant device 770a can serve as a session manager and one or more other participant devices (e.g., participant device 770b) can serve as a session managee. The manager can initiate transmission of signals (e.g., in response to instructions from the orchestrator 750), and the managee can receive the signals (and optionally transmit responses, as in the case of two-way measurements). For example, the first participant device 770a can transmit a signal (e.g., a sound signal) and the second participant device 770b can detect the signal and obtain a measurement parameter. This measurement parameter can be a time- of-flight. an acoustic attenuation, an absolute acoustic amplitude (e.g.. SPL), a relative acoustic distance (e g., if there are two recipient devices, a relative determination can be made that oneAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO device is acoustically further than the other from the transmitting device), an angular orientation, or other such measurement parameter. In at least some embodiments, both devices may be capable of receiving and detecting signals.

[0130] Although two participant devices 770 are shown here for simplicity', in various examples there may be any number of participant devices within the environment. Additionally, the orchestrator 750 and / or acoustic relationship analyzer 760 may be the same device as any one of the participant devices 770. In some examples, a single device may serve as the orchestrator 750, acoustic relationship analyzer 760, and a session participant 770.

[0131] Depending on the number and type of devices within an environment, the topology7and configuration of the roles may vary. For example, as shown in Figure 8 A, an orchestrator 750 is in communication with a single session participant device 770a, which serves as a manager device for session(s) with second participant device 770b and third participant device 770c (each of which are managee devices). The three participant devices 770a-c and the orchestrator 750 are each in communication with the acoustic relationship analyzer 760. Figure 8B illustrates the same configuration as Figure 8A but with additional participant devices 770d, 770e, and 770f included. Again, the manager device 770d receives instructions from the orchestrator 750 and emits signals to be detected via the managee devices 770e and 770f, which are then communicated to the acoustic relationship analyzer device 760 for estimation of the acoustic topology.

[0132] Figure 9 illustrates another example configuration of devices within an environment. As shown, the orchestrator 750, acoustic relationship analyzer 760, and session participant 770a are all combined within a single device (e.g., a single playback device) and are in wireless communication with a second session participant 770b. In alternative arrangements, the orchestrator 750 may be combined with (e.g., disposed within a common housing with or otherwise integrated with) any other device within the environment or may be a standalone device that does not itself participate in sessions. Similarly, the acoustic relationship analyzer 760 may be combined with any other device within the environment, or may be a standalone device that does not itself participate in sessions. b. Example Processes for Characterizing the Acoustic Topology

[0133] The acoustic topology characterization process relies on a variety of signals and detection methods, each offering unique advantages in different environments. One example approach utilizes ultrasonic signals (e.g., in the range of about 18-22 kHz). These high-frequency tones canAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO be useful for characterizing acoustic separation as they are inaudible to most humans but can be easily generated and detected by conventional audio hardware. Ultrasonic signals can be emitted as short chirps or sweeps, allowing for precise timing measurements while minimizing disruption to the home environment.

[0134] Another example method employs audible test tones, which may be selected to be as unobtrusive as possible. These signals might take the form of brief, low-volume sine sweeps across a wide frequency range. Although these may be audible, when scheduled during off-hours so as to not disturb users, these tones can provide rich data about the acoustic properties of the space, including frequency -dependent attenuation and reverberation characteristics.

[0135] Additionally or alternatively, audio signals generated as part of media playback can be used to characterize the acoustic topology. Instead of relying solely on dedicated test tones, the system can leverage sounds that are already part of the user experience, such as earcons (audio icons), startup sounds, and even music playback. This method offers several advantages. First, it reduces the need for intrusive, separate sessions, as the system can continuously refine its understanding of the acoustic environment during normal operation. For instance, when a device plays its startup sound, other devices in the network can listen for this familiar audio signature and use it to update their relative position and acoustic relationship. Similarly, during music playback, the system can analyze how the audio propagates between devices, using characteristics of the music itself as impromptu signals. This approach is particularly beneficial in scenarios in which users frequently move portable speakers or in which the acoustic properties of the space change often (e.g., opening / closing doors or windows). By opportunistically using these existing sounds, the system can maintain a more current and accurate acoustic topology without increasing its audible footprint in the home, thereby enhancing its ability to adapt to dynamic environments while preserving a seamless user experience.

[0136] In some examples, a receiver device can include two microphones that are spatially separated within the device. By using two microphones and calculating a time-of-flight for each, both the distance and the angular orientation of the receiver device with respect to the transmitter device can be obtained. Provided that the distance between the two receiver microphones is less than or equal to one half wavelength / . of the audio signals transmitted from the transmitter device, the path difference between the two receiver microphones will be between -X / 2 and + / 2. By measuring the phase of arrival at each microphone, the phase difference going from -180 degrees to + 180 degrees can also give a path difference varying from -X / 2 and + X / 2. Accordingly, theAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO orientation determination can be based on the relative phases of the received signal, while the distance determination can be based on the time-of-flight between the transmitter device and the receiver microphone.

[0137] In some examples, these devices can scan periodically, allowing the devices to maintain a history of signals received from the other devices. Reference and / or portable devices in accordance with several embodiments can scan for know n devices and collect characteristics (e.g., detected sound levels corresponding to a test tone) in a buffer (e.g., a ring buffer) and calculate statistics (e.g., weighted averages, variances, etc.) based on a history of collected signal characteristics. In some embodiments, signal characteristics and / or calculated statistics can be identified by each of the devices, pre-processed, and transmitted to an acoustic relationship analyzer device. In many embodiments, identified signal characteristics and / or calculated statistics of the signals can be stored in a matrix, that stores values for a given characteristic (e.g., acoustic attenuation).

[0138] In some examples, sound signals can be used to physically localize devices within an environment, which can be related to but distinct from the acoustic separation between devices. For example, a first device can emit a signature sound signal that can be detected by a microphone of a second device. The sound signal can be audible or inaudible (e.g., ultrasonic). If the transmitter and receiver devices are synchronized, a time-of-flight can be calculated between the transmission and receipt of the sound signal. Based on an estimated speed of sound in the environment, a distance measurement can therefore be obtained. In various examples, some or all of the devices within the environment can be configured to both transmit and receive sound signals. Additionally or alternatively, other modalities for determining physical separation between devices, or otherwise physically mapping components of a media playback system, can be used instead of or in conjunction with the acoustic topology’ characterization techniques described herein. Additional details of such spatial mapping of playback components can be found in commonly owned International Patent Application No. PCT / US2020 / 077185, filed September 28, 2022, titled “Spatial Mapping of Media Playback System Components,” which is hereby incorporated by reference in its entirety for all purposes.

[0139] Attenuation measurements provide crucial data points for characterizing the acoustic topology of a media playback system. By comparing the amplitude of the emitted signal from one playback device to the amplitude of the received signal at another playback device, the system can quantify the degree of acoustic separation between these devices. This attenuation measurementAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO takes into account various factors that affect sound propagation, such as distance, obstacles, and the acoustic properties of the environment. These techniques can be particularly effective in detecting the presence of walls, doors, or other physical barriers between playback devices, as these obstacles typically result in significantly greater signal attenuation. For example, two devices in adjacent rooms separated by a wall will likely show higher attenuation than two devices with a direct line of sight in the same room, even if the physical distances are similar. Furthermore, attenuation measurements can provide insights into the materials and structures present in the environment. Different materials absorb and reflect sound waves differently, leading to varying degrees of attenuation. For instance, heavy curtains or sound-absorbing panels may cause more attenuation than bare w alls, while glass surfaces might cause less attenuation due to their reflective properties.

[0140] The exchange of sound signals can follow a structured protocol to ensure comprehensive coverage of the environment. An example sequence might involve each device in the system taking turns as the signal emitter, while all other devices listen and record the received signals. This round-robin approach ensures that the acoustic relationship between every pair of devices is measured from both directions, allowing for more robust and accurate mapping. Depending on the orientation of the devices and the physical configuration of audio transducers and microphones within the devices, the acoustic distance between the two may be different in different directions. In some implementations, acoustic separation measurements between pairs of devices can be averaged or otherwise combined to generate a comprehensive acoustic topology.

[0141] In some implementations, multiple devices can emit signals simultaneously, using different frequencies or coded signals to distinguish betw een sources. This parallel approach can significantly reduce the time required for a complete measurement session, at the cost of increased computational complexity in signal processing.

[0142] For devices with microphone arrays, beamforming techniques can be employed to estimate the direction of arrival of acoustic signals. As noted above, by comparing time-of-arrival at different microphones within the array, the direction of the acoustic signal can be determined. This additional spatial information can further enhance the accuracy of the acoustic topology, particularly in complex environments with multiple rooms and openings.

[0143] In some implementations, the media playback system can utilize machine learning algorithms to improve signal detection and interpretation over time. This approach enables the system to continuously refine its understanding of the acoustic environment and enhance theAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO accuracy of its acoustic topology characterization. By analyzing patterns in successful and unsuccessful measurement attempts, these systems can adapt to the specific acoustic features of each environment, leading to more robust and accurate acoustic topologies over time. The machine learning model can be initially trained on a diverse dataset of acoustic measurements from various environments, encompassing different room layouts, materials, and device configurations. This initial training provides the system with a foundational understanding of how acoustic signals propagate in different settings. As the system operates in a specific environment, it collects data from each measurement session, including both successful and unsuccessful attempts at characterizing the acoustic relationships between devices.

[0144] The learning process involves several key components that work together to improve the system's performance. First, the algorithm engages in pattern recognition, identifying specific signal characteristics that correlate with successful or unsuccessful topology estimations. This might include recognizing certain time-of-flight patterns that suggest particular room layouts or identifying signal attributes that indicate the presence of obstacles between devices.

[0145] In various examples, recognized patterns using machine learning can be used for noise adaptation. For instance, as the system learns to differentiate between relevant acoustic signals and background noise specific to each environment. Over time, it becomes adept at recognizing and filtering out consistent noise sources such as HVAC systems, traffic, or household appliances, leading to cleaner and more reliable measurements.

[0146] As the system gains experience with different types of spaces, it may also develop the ability to classify environments and apply specialized processing techniques for each. For instance, it might develop distinct approaches for analyzing open-plan living areas versus smaller, enclosed rooms. This environmental classification allows the system to quickly adapt its measurement strategies to suit the specific acoustic challenges of each space.

[0147] Based on its ongoing learning, the system can dynamically adjust its signal processing parameters to optimize for specific acoustic conditions. This adaptive signal processing might involve modifying the frequency range of test signals, adjusting signal strength, or altering the duration of measurement periods. By fine-tuning these parameters, the system can achieve more accurate and reliable measurements across a wide range of acoustic environments.

[0148] As the machine learning model accumulates knowledge about a specific environment, it can make increasingly sophisticated inferences about the acoustic topology. The system can alsoAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO learn to recognize and account for regular changes in the acoustic environment, such as doors being opened or closed, or windows being opened during certain times of day. In some implementations, the model may also identify features and materials present in the environment based on observed acoustic behavior. For example, it might identify areas with sound-absorbing furniture or reflective surfaces, further refining its understanding of the acoustic space. As the system gains experience with a particular environment, it can even begin to predict how changes in device placement or room configuration might affect the acoustic topology', allowing for more rapid adaptation to user modifications.

[0149] In various implementations, the acoustic topology information allows for classification of acoustic links between pairs of devices, for instance separating the links into strong links, weak links, and no links. Such a categorization allows the system to make more informed decisions about audio playback, voice control, and device grouping.

[0150] Strong links indicate that devices are in the same acoustic space, typically within the same room or in very' open adjacent areas. These links are characterized by high signal strength, where the received signal has minimal attenuation compared to the transmitted signal. This may indicate a clear direct path with little evidence of significant acoustic obstructions between devices. The time-of-flight can be short, consistent with direct line-of-sight propagation, and / or there may be minimal reverberation, indicating an unobstructed path. For example, two speakers in a living room might have a strong link if a test signal sent from one speaker is received by the other with high fidelity and minimal delay, suggesting they're in the same unobstructed acoustic space.

[0151] Weak links suggest that devices are mutually audible but in different acoustic spaces. These links are identified by moderate signal attenuation, where the received signal is detectably weaker than the transmitted signal. There's may be indication of acoustic obstruction, with signal characteristics suggesting it has passed through or around obstacles, such as increased reverberation (indicating reflection off walls or other surfaces), and / or the time-of-flight may be longer or more variable than would be expected based on the physical distance alone. An example of a weak link might be between a speaker in the kitchen and another in the adjacent dining room. The test signal would be detectable but noticeably attenuated and with increased reverberation, suggesting it has traveled through a doorw ay or around a partial wall.

[0152] No links indicate that devices are effectively acoustically isolated from each other. These are characterized by extremely low or no detectable signal, where the test signal is either not detected at all or is below a predefined threshold of reliability’. If any signal is detected, it's oftenAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO sporadic and doesn't provide consistent measurements. A speaker in the basement and another on the second floor might have no link, as the test signal from one is not reliably detectable by the other, indicating strong acoustic isolation between these spaces.

[0153] To make these distinctions, the system can employ various methods. Signal strength analysis compares the amplitude of the received signal to the transmitted signal. For instance, acoustic attenuation thresholds can be used to distinguish strong, weak, and no link conditions. Acoustic attenuation thresholds, measured in decibels (dB), can be used to categorize the links between devices. For example, the system might define strong links as those with attenuation less than 20 dB, weak links as those with attenuation between 20 dB and 40 dB, and no link for attenuation greater than 40 dB. These thresholds can be adjusted based on the specific characteristics of the environment and the desired granularity of the acoustic map.

[0154] Another measurement modality that can be used to charactenze the acoustic separation between devices frequency response analysis, which examines how different frequencies in the test signal are attenuated. Another option is impulse response estimation and analysis, which analyzes the acoustic path between devices, revealing details about the nature of the link. The properties of the impulse response (e.g., the onset) can be used to estimate the time-of-flight (in the case of synchronized systems) or time-difference-of-arrival between two microphones (in the case of unsynchronized systems). Time-of-flight calculations measure the signal travel time between devices, comparing it with the expected time based on known physical distances. The system can also perform consistency checks, repeating measurements multiple times to ensure reliability', and bidirectional verification, comparing measurements in both directions between a pair of devices.

[0155] In some implementations, the acoustic topology' characterization process can include estimating up to three parameters between devices: the angle of arrival, the physical distance, and the acoustic separation. This multi-faceted approach allows for an understanding of how devices are positioned and how sound propagates between them. The process begins with the transmission of an over-the-air sweep signal from one device to another. This sweep is then recorded and analyzed using a combination of digital signal processing (DSP) techniques and machine learning (ML) algorithms to infer the three properties noted above. The angle of arrival (which may be determined with a precision of ±5°) can be calculated using time difference of arrival techniques. This method relies on the slight variations in arrival time of the signal at different microphones on the receiving device. The physical distance (which may measured to within ±30 cm) can beAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO determined using time-of-flight calculations, measuring how long it takes for the signal to travel from the transmitting device to the receiving device. The third parameter, the acoustic distance, can take into account signal attenuation and / or optionally a variety of other metrics, such as the direct-to-reverberant ratio. This measure can provide a coarse but valuable insight into the acoustic relationship between devices, even when they're not in direct line-of-sight.

[0156] In some instances, it may not be possible to reliably calculate all parameters in all situations. The angle of arrival and exact range measurements are most accurate in line-of-sight scenarios. To account for this, the system can include a confidence estimate for each measurement. In situations where line-of-sight is not available or the confidence is low, these metrics may not be included in the final acoustic topology’. Optionally, the system can be configured to always provide the approximate acoustic distance as long as the devices are mutually audible, ensuring that some level of acoustic relationship information is available even in challenging environments.

[0157] The result of this process is a rich, multi-layered topology of the household's acoustic landscape. Links between devices in this topology’ can carry’ different types of information - direction, range, and coarse acoustic distance - depending on what could be reliably measured. In cases where no metrics can be estimated at all. the system assumes that the devices are not mutually audible, and no link is created between them in the acoustic map. This approach allows the system to create a detailed and accurate representation of the acoustic relationships between devices, accounting for the complexities and variations in real-world environments. c. Example Acoustic Topologies

[0158] Figure 10 illustrates a visual representation of an estimated acoustic topology’ 1000 of a media playback system. The map comprises multiple clusters 1002a-1002d, each containing several nodes 770 (individually labeled as nodes 770a-770t) that represent individual components of the media playback system, such as playback devices or other suitable components. These nodes 770 are interconnected by links 1004 (individually labeled as links 1004a-1004r), which visually represent the acoustic connectivity’ (or alternatively, acoustic separation) between pairs of components. The links 1004 are determined based on calculated acoustic attenuation between each pair of connected components 770. The thickness of each link 1004 provides a visual indication of the acoustic proximity between the connected components - thicker lines suggest components that are acoustically closer, while thinner lines indicate greater acoustic separation.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0159] The acoustic topology 1000 distinguishes between different types of acoustic relationships through the visual representation of the links. Strong links, shown as the thickest lines, indicate devices that are in the same acoustic space, such as within the same room. Weak links, depicted by thinner lines, suggest components that are mutually audible but likely in different acoustic spaces, such as adjacent rooms in a home. When there is no link between nodes, it indicates that those components are mutually inaudible to each other.

[0160] To construct this acoustic topology7, the system can perform a series of acoustic measurements between each pair of components. As described elsewhere herein, this could involve each device in turn emitting a test signal, while all other devices listen and measure the received signal strength. The attenuation between devices can then be calculated by comparing the known transmitted signal strength to the received signal strength.

[0161] As noted above, acoustic attenuation thresholds, measured in decibels (dB). can be used to categorize the links between devices. For example, the system might define strong links as those with attenuation less than 20 dB, weak links as those with attenuation between 20 dB and 40 dB, and no link for attenuation greater than 40 dB. These thresholds can be adjusted based on the specific characteristics of the environment and the desired granularity7of the acoustic map.

[0162] The clustering of nodes 770 into groups 1002a-1002d suggests collections of devices that are in closer acoustic proximity to each other, potentially representing different rooms or areas within the overall environment. This acoustic topology 1000 provides a visual tool for understanding the spatial and acoustic relationships between components in the media playback system, allowing for optimized audio configurations and intelligent system behaviors based on the acoustic layout of the environment.

[0163] Figure 11 illustrates another example of a topographical acoustic topology 1100 for a media playback system within a home environment. This acoustic topology provides a visual representation of the acoustic relationships between various playback devices located in different rooms or areas of the house. The acoustic topology71100 includes several nodes 770, each representing a playback device or other component of the media playback system. These nodes are labeled with the room or area names where the devices are located, such as "Bedroom Roam,” “Kitchen,” “Living Room (LR),” “Living Room (RR),” “Living Room,” “Bathroom,” “Office,” and others. The positioning of these nodes on the map does not necessarily reflect their physical locations within the house, but rather their acoustic relationships to one another.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0164] Connecting these nodes are links 1004, which represent the acoustic separation between pairs of devices. The thickness and color intensity of these links indicate the degree of acoustic separation or connection between the devices. Thicker, darker lines suggest a stronger acoustic connection (less separation), while thinner, lighter lines indicate weaker acoustic connections (more separation).

[0165] For instance, the link 1004a between “Bedroom Roam” and “Orange Roam” is thick and dark, suggesting these devices are in close acoustic proximity, possibly in adjacent rooms or even within the same open space. Similarly, there are strong connections between “Living Room (RR),” “Bathroom,” and “Living Room (LR),” indicating these areas likely have open pathways for sound to travel between them. In contrast, the link between “Office” and “Orange Roam” is thinner and lighter, suggesting these areas are more acoustically separated, perhaps by walls or distance within the home. The “Kitchen” node shows vary ing degrees of connection to other areas, with stronger links to some living room devices and weaker links to others. Some nodes, like “Living Room” and “Living Room (LR).” have multiple strong connections, indicating they may be central points in an open-plan living area. The “Bathroom” node's relatively strong connections (links 100-4i, 1004k, and 10041) suggest it might be centrally located or have less sound insulation from surrounding areas.

[0166] This acoustic topology71100 provides valuable information for optimizing the media playback system's performance. It can be used to inform decisions about device grouping, volume balancing, and even voice control disambiguation in multi-room setups. For example, when receiving a voice command, the system could use this map to determine which device should respond based on acoustic proximity rather than just physical distance. The acoustic topology 1100 can also offers insights into the home's layout and acoustic properties, which could be useful for tailoring sound experiences, managing audio overflow between rooms, and creating more immersive multi-room audio setups. c. Spatial Mapping and Acoustic Topology

[0167] The distinction between acoustic separation and spatial separation can be useful in understanding the behavior of sound within complex environments. While spatial separation refers to the physical distance between playback devices, acoustic separation takes into account how sound actually propagates and is perceived within a space. This difference can be substantial, particularly in modem homes with open floor plans, varying architectural features, and diverse furnishings.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0168] Acoustic separation is influenced by a multitude of factors that go beyond mere physical distance. The presence of walls, doors, and other physical barriers plays a significant role, as these can dramatically attenuate sound even when devices are relatively close spatially. The materials used in construction and furnishing also have a major impact; for instance, hard surfaces like glass and concrete tend to reflect sound, potentially reducing acoustic separation, while soft furnishings and carpets absorb sound, potentially increasing it. Ceiling height, room shape, and the presence of openings like doorways or archways all contribute to the complex acoustic landscape of a home.

[0169] The practical outcomes of considering acoustic rather than spatial separation can be profound. Two speakers that are physically close but separated by a wall may have high acoustic separation, while two speakers that are farther apart but in the same open space may have low acoustic separation. This distinction is critical for features like voice control disambiguation. When a user issues a voice command, the system should respond based on acoustic proximity rather than physical distance, ensuring that the most audibly present device responds, not necessarily the physically closest one.

[0170] The media playback system's treatment of devices can vary- significantly based on acoustic topology. In terms of audio playback, devices with low acoustic separation might be automatically grouped for synchronous playback to create a more immersive experience. Conversely, devices with high acoustic separation might be kept separate to avoid unwanted audio bleed between rooms. The system could also adjust equalization settings dynamically; for instance, if two acoustically close speakers are playing the same content, their frequency responses might be adjusted to complement each other and avoid resonances.

[0171] For voice control functionality, the acoustic topology allows for more intelligent handling of multi-room scenarios. If a user moves from one room to another during a conversation with a voice assistant, the system can seamlessly transition the interaction to the most appropriate device based on acoustic proximity, maintaining continuity even as the user moves through acoustically distinct spaces.

[0172] The acoustic topology also enables more sophisticated volume management across a home. In scenarios where music is playing throughout multiple rooms, the system can intelligently adjust volumes based on acoustic relationships. For example, it might lower the volume in acoustically adjacent rooms to prevent sound clash, while maintaining higher volumes in more acoustically isolated areas.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0173] Furthermore, the acoustic topology can inform more advanced audio processing techniques. In home theater setups, for instance, the system could adjust delay times and levels for surround speakers based on their acoustic separation from the main speakers, rather than relying solely on physical distance. This could result in a more accurately timed and balanced surround sound experience, adapting to the unique acoustic properties of each room.

[0174] Ultimately, by basing its operations on acoustic rather than spatial separation, a media playback system can provide a more contextually aware, adaptive, and natural listening experience. It can make more intelligent decisions about audio routing, device grouping, voice control, and sound processing, all tailored to the actual acoustic realities of the user's environment rather than simplified spatial approximations.

[0175] In some implementations, spatial mapping information can be included or combined with the acoustic separation information used to estimate the acoustic topology of the environment. The integration of acoustic and spatial maps offers a powerful approach to creating a more comprehensive understanding of the audio environment. By combining these two distinct yet complementary perspectives, a media playback system can achieve a level of contextual awareness that surpasses what either map could provide independently.

[0176] One method of integration involves layering the acoustic separation data over a traditional spatial map. This approach creates a multi-dimensional representation of the environment where physical distances are augmented with acoustic relationship information. For instance, the system might start with a floorplan-like spatial map showing the physical layout of rooms and device locations. Overlaid on this could be a network of connections between devices, with the strength or color of these connections representing the degree of acoustic separation. This visual representation allows for quick identification of acoustic anomalies - areas where the acoustic behavior doesn't match what might be expected from the spatial layout alone.

[0177] Another integration technique involves creating a hybrid score or metric for each pair of devices that combines both spatial and acoustic information. This score could weight the acoustic separation more heavily in scenarios where audio quality and voice control are paramount, while giving more weight to spatial separation for features related to device grouping or user location tracking. By using this hybrid score, the system can make informed decisions that take into account both the physical and acoustic realities of the environment.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0178] The system could also employ a dynamic integration approach, where the relative importance of acoustic versus spatial information shifts based on the current context or user activity. For example, during audio playback, the acoustic topology might take precedence to optimize sound quality and synchronization. However, when a user is physically interacting with devices - such as moving a portable speaker - the spatial map might become more relevant for tracking these changes and updating the system's understanding of the environment.

[0179] The integration of acoustic and spatial data also opens up possibilities for more sophisticated room correction and audio processing techniques. By understanding both the physical dimensions of a room and its acoustic characteristics, the system could apply highly tailored equalization and sound field corrections. This could extend beyond simple distance-based adjustments to account for complex acoustic phenomena like standing waves, reflections, and frequency -dependent absorption that are unique to each space.

[0180] Furthermore, this integrated approach could enhance the system's ability to adapt to changes in the environment. For example, if a door is opened or closed between rooms, the acoustic map might register a change in separation between certain devices. By cross-referencing this with the spatial map, the system could infer the likely cause of this change and adjust its behavior accordingly, perhaps by re-routing audio or updating voice control zones.

[0181] In scenarios involving multi-room or whole-home audio, the combined acoustic and spatial awareness allows for creating virtual sound zones that align with both the physical layout and the acoustic realities of the space. This could enable more natural and intuitive audio experiences as users move through the home, with sound following them in a way that feels organic and responsive to the environment. d. Initialization. Updating, and Scheduling

[0182] The maintenance of an accurate and up-to-date acoustic topology can be beneficial for continued performance in multi-room audio systems, particularly as device locations or other features of the environment (e.g., furniture positioning) can change. Various scheduling approaches can be employed, each offering unique benefits to accommodate different user needs and environmental conditions.

[0183] In one example, periodic scheduled updates can be used, such as performing acoustic measurements at regular intervals, typically during quiet hours like early morning. This method provides consistent updates but may not always capture sudden changes in the environment. ToAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO address this limitation, event-triggered updates can be implemented, initiating acoustic measurement processes in response to specific occurrences that may affect the acoustic environment, such as the addition or removal of devices, device movement (e.g., detected by accelerometers), or power cycles that might indicate device relocation. Additionally or alternatively, automatic scheduling on a per-household basis can be determined by analyzing each household’s routines to select an appropriate moment in which the media playback system is generally dormant.

[0184] For users who prefer more control, manual updates allow initiation of acoustic measurement sessions at will through a control device, a voice command, or otherwise. This may be particularly useful after intentional changes to the home layout or audio setup. An adaptive scheduling system offers a more intelligent solution by learning from usage patterns and environmental factors to determine optimal times for acoustic measurement updates. This might involve identifying consistently quiet periods or prioritizing updates for the most active areas based on recent usage.

[0185] Instead of full system-wide mapping sessions, an incremental update approach can be employed, updating subsets of devices or specific areas of the home in a rolling fashion. This can help distribute the processing load and minimize disruption while maintaining an up-to-date overall map. A background continuous acoustic measurement approach offers yet another alternative, performing low -intensity acoustic measurements during normal operation to gradually refine the understanding of acoustic relationships between devices.

[0186] In some implementations, a hybrid approach is used. For instance, a base schedule of weekly updates could be supplemented by event-triggered updates and continuous background refinement. In environments where acoustic properties change seasonally, such as homes where windows are often open in summer or heavily decorated during holidays, the system can be programmed for more frequent updates during transitional periods.

[0187] Before initiating a measurement session, the system can perform checks to ensure all devices are idle, and optionally conducts a microphone check to confirm low background noise levels. It can adapt the volume of acoustic signals based on ambient noise conditions, particularly in the near-ultrasonic range. Advanced implementations may incorporate machine learning to analyze historical data and predict optimal acoustic measurement times based on household habits. The system may also include event-based triggers to initiate updates when device movement is suspected, such as after power cycles or when accelerometer events are detected.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0188] By offering this variety of scheduling options and implementation techniques, the system can adapt to diverse user preferences and environmental conditions. This flexibility ensures that the acoustic topology remains an accurate and valuable tool for enhancing the multi-room audio experience, accounting for various changes in the household acoustic landscape over time. The result is a dynamic, responsive system that maintains high-quality performance in audio playback, voice control, and other features that rely on accurate spatial and acoustic information.

[0189] Among examples, the acoustic topology7information generated or obtained at one device can be replicated and / or maintained across other devices within the media playback system or at remote locations. Once the initial acoustic measurement process is complete, the system aggregates the individual measurements or 'legs” between devices into a comprehensive acoustic topology. This acoustic topology may not necessarily be a single, fully connected graph, but rather could consist of disjoint subgraphs representing locally connected areas within the environment. For instance, there might be distinct clusters for upstairs and downstairs areas, or for different wings of a large house. Once constructed, this acoustic measurement can then be replicated across the network, ensuring that all devices have access to the most up-to-date information about the acoustic topology of the environment.

[0190] The system can apply an intelligent approach to partial re-measuring, caching, and cache invalidation to maintain the accuracy of the acoustic topology while minimizing unnecessary7processing and network traffic. When a change is detected in the netw ork, such as a device being moved (e.g., as detected by an accelerometer) or a device being powered off and on again, the system may not immediately remap the entire environment. Instead, the system identifies the relevant parts of the network that are likely to be affected by the change and automatically remeasures just those sections. This targeted approach allows for quick updates to the topology7without the need for a full, time-consuming re-measurement process.

[0191] To further optimize the system's performance, the acoustic topology can be cached on each device. This caching mechanism can be designed with the understanding that acoustic relationships can change over time due to various factors such as furniture rearrangement, seasonal changes (e.g., open windows in summer), or even the presence of people in the room. To account for this, each link in the map can be associated w ith an expiry time. This expiry time reflects how7quickly the system believes each parameter of the link may become stale or unreliable. When a link's expiry time is reached, it triggers a re-measurement of that specific connection, ensuring that the acoustic topology remains accurate without requiring constant, system-wide updates.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0192] The system may take an adaptive approach to managing these expiry times. Over time, it adjusts the timeouts intelligently based on the consistency of previously experienced measurements. For example, if a particular link between two devices shows high consistency in its measurements over multiple acoustic measurement sessions, the system might extend the expiry time for that link, reducing the frequency of unnecessary re-measurements. Conversely, if a link shows high variability in its measurements, the system might shorten its expiry' time to ensure more frequent updates and maintain accuracy. e. Example User Experiences Based on Acoustic Topology'

[0193] The acoustic topology7enables a variety of enhanced functionalities and use cases in a multi-room audio system, significantly improving user experiences and system performance. These applications leverage the understanding of acoustic relationships between devices to provide more intuitive, context-aware, and acoustically optimized interactions.

[0194] Among examples, voice commands can be disambiguated by relying on acoustic topology information. For instance, in scenarios where multiple playback devices are active in different rooms, the system can more accurately determine which device should respond to voice commands. For example, if a user in the living room says “Stop the music” while music is playing in both the living room and a nearby bedroom, the system can use the acoustic topology to identify that the living room device is acoustically closer to the user. This allows the system to stop the music only in the living room, leaving the bedroom audio unaffected. The system can even handle more complex scenarios, such as when a user is standing in a doorway between two rooms, by analyzing the acoustic properties of the voice command itself to determine the most appropriate device to respond.

[0195] In some implementations, acoustic topology information can allow for intelligent grouping and routing of audio playback, for instance enabling an intelligent “play near me” functionality. When a user issues a “play” command, instead of simply activating the physically nearest device, the system identifies which devices are in the same acoustic space as the user. In an open-plan kitchen / dining area, for instance, a request for music playback could automatically group and activate all devices within that acoustically connected space. This creates a more immersive and cohesive listening experience, as the system understands the acoustic layout of the area rather than relying solely on physical device locations. The system can even adjust the balance and volume of each device based on their acoustic relationships to optimize the sound field for the user's position.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0196] Dynamic home theater configuration is another area in which acoustic topology proves useful. When a user introduces a portable speaker into a room with existing home theater components, the system detects the acoustic proximity of the new device and can automatically incorporate it into the setup. For example, it might recognize that the portable speaker is positioned behind the listening area and automatically configure it as a rear surround channel. This enhances the overall audio experience without requiring manual configuration. The system can continually monitor the acoustic relationships between devices, allowing it to adapt in real-time to changes in speaker positions or room layout, ensuring optimal home theater performance at all times.

[0197] Adaptive EQ and audio rendering can become more sophisticated with the benefit of acoustic topology information. The system can dynamically adjust equalization and audio rendering based on the acoustic relationships between devices. For closely positioned speakers, it might adjust their frequency responses to prevent unwanted resonances or phase cancellations. In larger spaces where devices are acoustically separated but part of the same playback group, the system could emphasize different frequency ranges for each device to create a more balanced overall sound. This adaptive approach could even account for room acoustics, adjusting the audio output to compensate for reflective surfaces or absorptive materials in the environment.

[0198] Efficient multi-room playback can also be optimized using the acoustic topology. As users move through different areas of a house where music is playing, the system can smoothly transition audio between acoustically connected spaces. For instance, as a user moves from the living room to the kitchen, the system might gradually lower the volume in the living room while raising it in the kitchen, creating a seamless listening experience. This transition can be further refined based on the user's movement speed and direction, anticipating their destination and preparing the audio environment accordingly.

[0199] Voice assistant interactions may likewise benefit from an understanding of the acoustic topology of an environment. During multi-tum conversations with a voice assistant, if a user moves from one room to another acoustically connected space, the system can seamlessly transition the interaction to the most appropriate device in the new location. This creates the illusion of the voice assistant “following” the user through the house, maintaining context and continuity in the conversation. The system can even handle scenarios where multiple users are interacting with voice assistants in different parts of the house, managing these conversations separately based on their acoustic locations. Additional details regarding such persistent interactions with a voice assistant service can be found in commonly owned U.S. Patent No.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO11,120,794, issued September 14, 2021, titled “Voice Assistance Persistence Across Multiple Network Microphone Devices,” which is hereby incorporated by reference in its entirety for all purposes.

[0200] As another example, an optimized “Party7Mode” may leverage acoustic topology7for intelligent audio management during large gatherings. When “party mode” playback is initiated (i.e., playing back audio content synchronously across all available playback devices within an environment), the system can identify acoustically isolated zones, such as upstairs bedrooms, where lower volumes might be more appropriate, while maximizing synchronization and volume levels in open, acoustically connected areas where most guests are likely to congregate. This optimization can dynamically7adjust throughout the event, responding to changes in guest locations and noise levels to maintain the ideal audio environment. The system might even incorporate adaptive noise cancellation in certain areas to improve conversation clarify while maintaining background music levels.

[0201] These use cases demonstrate how the acoustic topology can significantly enhance the functionality and user experience of a multi-room audio system, providing more intuitive, context- aware, and acoustically optimized interactions. f. Example Methods for Characterizing Acoustic Topology

[0202] Figures 12-15 illustrate flow diagrams of example processes for characterizing the acoustic topology of component devices of a media playback system. These processes can be implemented by any of the playback devices, NMDs, or controller devices disclosed and / or described herein, or any other device now known or later developed. Various examples of the processes described herein include one or more operations, functions, and actions. Although blocks are illustrated in sequential order, these blocks may also be performed in parallel, and / or in a different order than the order disclosed and described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed based upon a desired implementation.

[0203] Figure 12 illustrates a flowchart 1200 depicting a process for estimating the acoustic topology of a media playback system. This process involves multiple playback devices and is designed to characterize the acoustic relationships between these devices within an environment. The process begins at block 1202, where a first playback device transmits an acoustic signal. This signal may' take various forms, such as an audible test tone, an ultrasonic chirp, or a swept sineAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO wave, which may be designed to provide acoustic information while minimizing disruption to the user experience.

[0204] In block 1204, a second playback device receives the acoustic signal transmitted by the first device. This reception can be accomplished using one or more microphones integrated into the second playback device. In block 1206, an acoustic separation measurement parameter is obtained based on the received acoustic signal. This parameter quantifies the acoustic relationship between the transmitting and receiving devices. It may include or be based on metrics such as signal attenuation, time-of-flight, or frequency response characteristics as described above.

[0205] Finally, block 1208 represents the characterization of the acoustic topology based on the acoustic separation measurement parameter(s). This step can involve aggregating data from multiple device pairs and applying algorithms to construct a comprehensive model of the acoustic relationships within the playback system. The resulting topology provides a beneficial understanding of how sound propagates between devices in the environment, which can be used to optimize various aspects of the system's performance.

[0206] This process 1200 may be repeated with different device pairs taking turns as transmitter and receiver to build a complete picture of the acoustic environment. As such, this flowchart represents a building block of the overall acoustic topology characterization methods described throughout.

[0207] Figure 13 illustrates a flowchart 1300 depicting a process for utilizing acoustic topology information to enhance voice control functionality' in a media playback system. This process demonstrates how the system leverages its understanding of the acoustic environment to provide more intuitive and context-aware responses to voice commands.

[0208] The process begins at block 1302 with obtaining acoustic topology information. This information, derived through the methods described earlier in the application, provides a comprehensive map of the acoustic relationships between playback devices in the environment. In block 1304, a first playback device detects a voice input comprising a playback command. This detection typically involves the use of one or more microphones integrated into the playback device and may include wake word detection and voice recognition processes.

[0209] Block 1306 shows the system's response to the detected voice input. Based on the acoustic topology information, the playback command is applied to other playback devices within the same acoustic space as the first playback device. This intelligent application of the commandAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO demonstrates the system's ability to understand which devices are acoustically relevant to the user's current location, even if they may not be the physically closest devices.

[0210] Figure 14 presents a flowchart 1400 illustrating another process that utilizes acoustic topology information, this time to enable intelligent grouping and synchronous playback of media content. The process begins at block 1402 with obtaining acoustic topology information, similar to the previous figure.

[0211] In block 1404, a first playback device receives a command to initiate media playback. This command could come from various sources, such as a mobile app, a voice input, or a physical button press on the device. Block 1406 demonstrates how the system uses the acoustic topology information to automatically group the first playback device with other playback device(s) within the same acoustic space. This grouping is based on the acoustic relationships between devices rather than their physical proximity, ensuring a more contextually appropriate audio experience. Finally, block 1408 shows the result of this intelligent grouping: the system synchronously plays back media content via the grouped playback devices. This synchronous playback ensures a cohesive and immersive listening experience across the acoustically related devices.

[0212] Figure 15 illustrates a flowchart 1500 depicting a process for dynamically integrating a portable playback device into a home theatre system based on acoustic topology information. This process demonstrates the system's ability to adapt to changes in device placement and optimize the audio experience in real-time.

[0213] The process begins at block 1502, where the system determines that a portable playback device is within a predetermined acoustic separation distance of a home theatre zone. This determination can be made using the acoustic topology' information obtained through the methods described earlier in the application. The “acoustic separation distance” refers to the degree of acoustic connectivity between devices, rather than physical distance, allowing for more contextually appropriate device integration.

[0214] In block 1504, upon determining that the portable device is acoustically proximate to the home theatre zone, the system automatically adds the portable playback device to the home theatre zone. This automatic integration eliminates the need for manual reconfiguration by the user, enhancing the system's ease of use and adaptability. Finally, block 1506 shows the result of this dynamic integration: the system synchronously plays back home theatre audio content via the expanded home theatre zone, which now includes the newly added portable device.Attomey Docket No 24-0201-PCT Fortem Reference No. SNS.152WO

[0215] This process illustrates a practical application of the acoustic topology characterization technology7, demonstrating how it enables the media playback system to be more responsive to changes in the acoustic environment. By utilizing acoustic topology information, the media playback system can seamlessly7incorporate portable devices into existing audio setups, potentially expanding the home theatre experience beyond traditional fixed speaker arrangements.IV. Conclusion

[0216] 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.

[0217] 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 ty pically used by those skilled in the art to most effectively conveys 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 examples 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 examples. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the forgoing description of examples.

[0218] 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.V. ExamplesAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0219] The present technology' is illustrated, for example, according to various aspects described below. Various examples of aspects of the present technology' are described as numbered examples for convenience. These are provided as examples and do not limit the present technology. It is noted that any of the dependent examples may be combined in any combination, and placed into a respective independent example. The other examples can be presented in a similar manner.

[0220] Example 1. A media playback system comprising a plurality of playback devices, the system configured to: (a) play back, via an audio transducer of a first playback device, an acoustic signal; (b) for each of the other playback devices: detect, via one or more microphones of the other playback device, sound data while the first playback device plays back the acoustic signal; based at least in part on the detected sound data, obtain an acoustic separation parameter that indicates an acoustic separation between the first playback device and the other playback device; (c) repeat steps (a) and (b) for each of the other playback devices, such that each of the other playback devices plays back an acoustic signal in turn while each of the remaining playback devices detects sound data; based on the obtained acoustic separation parameters, characterize an acoustic topology of the plurality of playback devices; and based on the acoustic topology characterization, change a state of at least one of the playback devices.

[0221] Example 2. The media playback system of any preceding Example, wherein characterizing the acoustic topology' comprises, for each pair of playback devices, combining the two obtained acoustic separation parameters that characterize the acoustic separation between the pair of playback devices.

[0222] Example 3. The media playback system of any preceding Example, wherein the system is further configured to, prior to playing back the acoustic signal, perform a microphone check to confirm background noise level is below a predetermined threshold.

[0223] Example 4. The media playback system of any preceding Example, wherein each playback device is configured to store a local copy of the acoustic topology' characterization.

[0224] Example 5. The media playback system of any preceding Example, wherein the system is further configured to, for each of the other playback devices, and based at least in part on the detected sound data, obtain a physical distance parameter.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0225] Example 6. The media playback system of any preceding Example, wherein the system is further configured to, for each of the other playback devices, and based at least in part on the detected sound data, obtain an angle-of-arrival parameter.

[0226] Example 7. The media playback system of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0227] Example 8. The media playback system of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.

[0228] Example 9. The media playback system of any preceding Example, wherein characterizing the acoustic topology comprises delineating acoustic separation between pairs of playback devices, including strong links, weak links, and no link.

[0229] Example 10. The media playback system of any preceding Example, wherein the system is further configured to update the acoustic topology characterization based on a detected change in the media playback system.

[0230] Example 11. The media playback system of any preceding Example, wherein the system is further configured to transmit the acoustic topology characterization to at least one of the other playback devices.

[0231] Example 12. The media playback system of any preceding Example, wherein the system is further configured to: detect, via one or more microphones of the first playback device, a voice input comprising a playback command; and cause the playback command to be applied to other playback devices within the same acoustic space as the first playback device.

[0232] Example 13. The media playback system of any preceding Example, wherein the system is further configured to: detect, via one or more microphones of the first playback device, a voice input; and provide feedback indicating detection of voice input via both the first playback device and other playback devices within the same acoustic space.

[0233] Example 14. The media playback system of any preceding Example, wherein the system is further configured to: receive a command to initiate playback at the first playback device; automatically group the first playback device with other playback devices within the same acoustic space; and synchronously play back audio via the grouped playback devices.

[0234] Example 15. The media playback system of any preceding Example, wherein the system is further configured to: determine that a portable playback device is within a predeterminedAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO acoustic separation distance of a home theatre bonded zone; automatically add the portable playback device into the home theatre bonded zone; and synchronously play back home theatre audio content via the home theatre bonded zone.

[0235] Example 16. A method performed by a media playback system comprising a plurality of playback devices, the method comprising: (a) playing back, via an audio transducer of a first playback device, an acoustic signal; (b) for each of the other playback devices: detecting, via one or more microphones of the other playback device, sound data while the first playback device plays back the acoustic signal; based at least in part on the detected sound data, obtaining an acoustic separation parameter that indicates an acoustic separation between the first playback device and the other playback device; (c) repeating steps (a) and (b) for each of the other playback devices, such that each of the other playback devices plays back an acoustic signal in turn while each of the remaining playback devices detects sound data; based on the obtained acoustic separation parameters, characterizing an acoustic topology of the plurality of playback devices; and based on the acoustic topology characterization, changing a state of at least one of the playback devices.

[0236] Example 17. The method of any preceding Example, wherein characterizing the acoustic topology comprises, for each pair of playback devices, combining the two obtained acoustic separation parameters that indicate the acoustic separation between the pair of playback devices.

[0237] Example 18. The method of any preceding Example, further comprising, prior to playing back the acoustic signal, performing a microphone check to confirm background noise level is below a predetermined threshold.

[0238] Example 19. The method of any preceding Example, wherein each playback device stores a local copy of the acoustic topology characterization.

[0239] Example 20. The method of any preceding Example, further comprising, for each of the other playback devices, and based at least in part on the detected sound data, obtaining a physical distance parameter.

[0240] Example 21. The method of any preceding Example, further comprising, for each of the other playback devices, and based at least in part on the detected sound data, obtaining an angle- of-arrival parameter.

[0241] Example 22. The method of any preceding Example, wherein the acoustic signal comprises an inaudible signal.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0242] Example 23. The method of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.

[0243] Example 24. The method of any preceding Example, wherein characterizing the acoustic topology comprises delineating acoustic separation between pairs of playback devices, including strong links, weak links, and no link.

[0244] Example 25. The method of any preceding Example, further comprising updating the acoustic topology characterization based on a detected change in the media playback system.

[0245] Example 26. The method of any preceding Example, further comprising transmitting the acoustic topology characterization to at least one of the other playback devices.

[0246] Example 27. The method of any preceding Example, further comprising: detecting, via one or more microphones of the first playback device, a voice input comprising a playback command; and causing the playback command to be applied to other playback devices within the same acoustic space as the first playback device.

[0247] Example 28. The method of any preceding Example, further comprising: detecting, via one or more microphones of the first playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and other playback devices within the same acoustic space.

[0248] Example 29. The method of any preceding Example, further comprising: receiving a command to initiate playback at the first playback device; and automatically grouping the first playback device with other playback devices within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

[0249] Example 30. The method of any preceding Example, further comprising: determining that a portable playback device is within a predetermined acoustic separation distance of a home theatre bonded zone; automatically adding the portable playback device into the home theatre bonded zone; and synchronously playing back home theatre audio content via the home theatre bonded zone.

[0250] Example 31. One or more computer-readable media storing instructions that, when executed by one or more processors of a media playback system, cause the media playback system to perform operations comprising: (a) playing back, via an audio transducer of a first playback device, an acoustic signal; (b) for each of the other playback devices: detecting, via one or more microphones of the other playback device, sound data while the first playback device plays backAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO the acoustic signal; based at least in part on the detected sound data, obtaining an acoustic separation parameter that indicates an acoustic separation between the first playback device and the other playback device; (c) repeating steps (a) and (b) for each of the other playback devices, such that each of the other playback devices plays back an acoustic signal in turn while each of the remaining playback devices detects sound data; based on the obtained acoustic separation parameters, characterizing an acoustic topology of the plurality of playback devices; and based on the acoustic topology' characterization, changing a state of at least one of the playback devices.

[0251] Example 32. The one or more computer-readable media of any preceding Example, wherein characterizing the acoustic topology comprises, for each pair of playback devices, combining the two obtained acoustic separation parameters that indicate the acoustic separation between the pair of playback devices.

[0252] Example 33. The one or more computer-readable media of any preceding Example, wherein the operations further comprise, prior to playing back the acoustic signal, performing a microphone check to confirm background noise level is below a predetermined threshold.

[0253] Example 34. The one or more computer-readable media of any preceding Example, wherein the operations further comprise storing a local copy of the acoustic topology' characterization on each playback device.

[0254] Example 35. The one or more computer-readable media of any preceding Example, wherein the operations further comprise, for each of the other playback devices, and based at least in part on the detected sound data, obtaining a physical distance parameter.

[0255] Example 36. The one or more computer-readable media of any preceding Example, wherein the operations further comprise, for each of the other playback devices, and based at least in part on the detected sound data, obtaining an angle-of-arrival parameter.

[0256] Example 37. The one or more computer-readable media of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0257] Example 38. The one or more computer-readable media of any preceding Example, wherein the acoustic signal comprises a plurality' of sine sweeps.

[0258] Example 39. The one or more computer-readable media of any preceding Example, wherein characterizing the acoustic topology comprises delineating acoustic separation between pairs of playback devices, including strong links, weak links, and no link.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0259] Example 40. The one or more computer-readable media of any preceding Example, wherein the operations further comprise updating the acoustic topology' characterization based on a detected change in the media playback system.

[0260] Example 4E The one or more computer-readable media of any preceding Example, wherein the operations further comprise transmitting the acoustic topology characterization to at least one of the other playback devices.

[0261] Example 42. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: detecting, via one or more microphones of the first playback device, a voice input comprising a playback command; and causing the playback command to be applied to other playback devices within the same acoustic space as the first playback device.

[0262] Example 43. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: detecting, via one or more microphones of the first playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and other playback devices within the same acoustic space.

[0263] Example 44. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: receiving a command to initiate playback at the first playback device; automatically grouping the first playback device with other playback devices within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

[0264] Example 45. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: determining that a portable playback device is within a predetermined acoustic separation distance of a home theatre bonded zone; automatically adding the portable playback device into the home theatre bonded zone; and synchronously playing back home theatre audio content via the home theatre bonded zone.

[0265] Example 46. A first playback device comprising: one or more processors; an audio transducer; and memory storing instructions that, when executed by the one or more processors, cause the first playback device to: transmit, via the audio transducer, an acoustic signal; receive, from a second playback device, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; and based on theAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO acoustic separation parameter, cause a change a state of the first playback device or the second playback device.

[0266] Example 47. The first playback device of any preceding Example, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

[0267] Example 48. The first playback device of any preceding Example, wherein, prior to the first playback device transmitting the acoustic signal, the second playback device performs a microphone check to confirm background noise level is below a predetermined threshold.

[0268] Example 49. The first playback device of any preceding Example, wherein the first playback device or the second playback device is configured to, based at least in part on the detected acoustic signal, obtain a physical distance parameter.

[0269] Example 50. The first playback device of any preceding Example, wherein the second playback device is configured to, based at least in part on the detected acoustic signal, obtain an angle-of-arrival parameter.

[0270] Example 51. The first playback device of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0271] Example 52. The first playback device of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.

[0272] Example 53. The first playback device of any preceding Example, wherein the first playback device is further configured to: detect, via one or more microphones of the first playback device, a voice input comprising a playback command; and cause the playback command to be applied to the second playback device, wherein the second playback device is in the same acoustic space as the first playback device.

[0273] Example 54. The first playback device of any preceding Example, wherein the first playback device is further configured to: detect, via one or more microphones of the first playback device, a voice input; and provide feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.

[0274] Example 55. The first playback device of any preceding Example, wherein the first playback device is further configured to: receive a command to initiate playback at the firstAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO playback device; automatically group the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously play back audio via the grouped playback devices.

[0275] Example 56. A second playback device comprising: one or more processors; one or more microphones; and memory storing instructions that, when executed by the one or more processors, cause the second playback device to: detect, via the one or more microphones, an acoustic signal transmitted by a first playback device; determine, based on the detected sound signal, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; based on the acoustic separation parameter, cause a change a state of the first playback device or the second playback device.

[0276] Example 57. The second playback device of any preceding Example, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

[0277] Example 58. The second playback device of any preceding Example, wherein, prior to the first playback device transmitting the acoustic signal, the second playback device performs a microphone check to confirm background noise level is below a predetermined threshold.

[0278] Example 59. The second playback device of any preceding Example, wherein the second playback device or the second playback device is configured to, based at least in part on the detected acoustic signal, obtain a physical distance parameter.

[0279] Example 60. The second playback device of any preceding Example, wherein the second playback device is configured to, based at least in part on the detected acoustic signal, obtain an angle-of-arrival parameter.

[0280] Example 61. The second playback device of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0281] Example 62. The second playback device of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.

[0282] Example 63. The second playback device of any preceding Example, wherein the second playback device is further configured to: detect, via one or more microphones of the second playback device, a voice input comprising a playback command; and cause the playback command to be applied to the first playback device, wherein the first playback device is in the same acoustic space as the second playback device.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0283] Example 64. The second playback device of any preceding Example, wherein the second playback device is further configured to: detect, via one or more microphones of the first playback device, a voice input; and provide feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.

[0284] Example 65. The second playback device of any preceding Example, wherein the second playback device is further configured to: receive a command to initiate playback at the second playback device; automatically group the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously play back audio via the grouped playback devices.

[0285] Example 66. A method performed by a first playback device, the method comprising: transmitting, via an audio transducer of the first playback device, an acoustic signal; receiving, from a second playback device, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; and based on the acoustic separation parameter, causing a change in state of the first playback device or the second playback device.

[0286] Example 67. The method of any preceding Example, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

[0287] Example 68. The method of any preceding Example, further comprising, prior to transmitting the acoustic signal, receiving confirmation from the second playback device that a background noise level is below a predetermined threshold.

[0288] Example 69. The method of any preceding Example, further comprising obtaining a physical distance parameter based at least in part on the acoustic signal.

[0289] Example 70. The method of any preceding Example, wherein the acoustic separation parameter includes an angle-of-arrival parameter obtained by the second playback device.

[0290] Example 71. The method of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0291] Example 72. The method of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0292] Example 73. The method of any preceding Example, further comprising: detecting, via one or more microphones of the first playback device, a voice input comprising a playback command; and causing the playback command to be applied to the second playback device, wherein the second playback device is in the same acoustic space as the first playback device.

[0293] Example 74. The method of any preceding Example, further comprising: detecting, via one or more microphones of the first playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.

[0294] Example 75. The method of any preceding Example, further comprising: receiving a command to initiate playback at the first playback device; automatically grouping the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

[0295] Example 76. A method performed by a second playback device, the method comprising: detecting, via one or more microphones of the second playback device, an acoustic signal transmitted by a first playback device; determining, based on the detected acoustic signal, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; based on the acoustic separation parameter, causing a change in state of the first playback device or the second playback device.

[0296] Example 77. The method of any preceding Example, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

[0297] Example 78. The method of any preceding Example, further comprising, prior to detecting the acoustic signal, performing a microphone check to confirm background noise level is below a predetermined threshold.

[0298] Example 79. The method of any preceding Example, further comprising obtaining a physical distance parameter based at least in part on the detected acoustic signal.

[0299] Example 80. The method of any preceding Example, further comprising obtaining an angle-of-arrival parameter based at least in part on the detected acoustic signal.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO

[0300] Example 81. The method of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0301] Example 82. The method of any preceding Example, wherein the acoustic signal comprises a plurality' of sine sweeps.

[0302] Example 83. The method of any preceding Example, further comprising: detecting, via the one or more microphones of the second playback device, a voice input comprising a playback command; and causing the playback command to be applied to the first playback device, wherein the first playback device is in the same acoustic space as the second playback device.

[0303] Example 84. The method of any preceding Example, further comprising: detecting, via the one or more microphones of the second playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.

[0304] Example 85. The method of any preceding Example, further comprising: receiving a command to initiate playback at the second playback device; automatically grouping the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

[0305] Example 86. One or more computer-readable media storing instructions that, when executed by one or more processors of a first playback device, cause the first playback device to perform operations comprising: transmitting, via an audio transducer of the first playback device, an acoustic signal; receiving, from a second playback device, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; and based on the acoustic separation parameter, causing a change in state of the first playback device or the second playback device.

[0306] Example 87. The one or more computer-readable media of any preceding Example, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

[0307] Example 88. The one or more computer-readable media of any preceding Example, wherein the operations further comprise, prior to transmitting the acoustic signal, receivingAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO confirmation from the second playback device that a background noise level is below a predetermined threshold.

[0308] Example 89. The one or more computer-readable media of any preceding Example, wherein the operations further comprise obtaining a physical distance parameter based at least in part on the acoustic signal.

[0309] Example 90. The one or more computer-readable media of any preceding Example, wherein the acoustic separation parameter includes an angle-of-arrival parameter obtained by the second playback device.

[0310] Example 91. The one or more computer-readable media of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0311] Example 92. The one or more computer-readable media of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.

[0312] Example 93. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: detecting, via one or more microphones of the first playback device, a voice input comprising a playback command; and causing the playback command to be applied to the second playback device, wherein the second playback device is in the same acoustic space as the first playback device.

[0313] Example 94. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: detecting, via one or more microphones of the first playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.

[0314] Example 95. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: receiving a command to initiate playback at the first playback device; automatically grouping the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

[0315] Example 96. One or more computer-readable media storing instructions that, when executed by one or more processors of a second playback device, cause the second playback device to perform operations comprising: detecting, via one or more microphones of the second playback device, an acoustic signal transmitted by a first playback device; determining, based onAttomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO the detected acoustic signal, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; based on the acoustic separation parameter, causing a change in state of the first playback device or the second playback device.

[0316] Example 97. The one or more computer-readable media of any preceding Example, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

[0317] Example 98. The one or more computer-readable media of any preceding Example, wherein the operations further comprise, prior to detecting the acoustic signal, performing a microphone check to confirm background noise level is below a predetermined threshold.

[0318] Example 99. The one or more computer-readable media of any preceding Example, wherein the operations further comprise obtaining a physical distance parameter based at least in part on the detected acoustic signal.

[0319] Example 100. The one or more computer-readable media of any preceding Example, wherein the operations further comprise obtaining an angle-of-arrival parameter based at least in part on the detected acoustic signal.

[0320] Example 101. The one or more computer-readable media of any preceding Example, wherein the acoustic signal comprises an inaudible signal.

[0321] Example 102. The one or more computer-readable media of any preceding Example, wherein the acoustic signal comprises a plurality of sine sweeps.

[0322] Example 103. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: detecting, via the one or more microphones of the second playback device, a voice input comprising a playback command; and causing the playback command to be applied to the first playback device, wherein the first playback device is in the same acoustic space as the second playback device.

[0323] Example 104. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: detecting, via the one or more microphones of the second playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.Attomey Docket No 24-0201-PCT Fortem Reference No. SNS.152WO

[0324] Example 105. The one or more computer-readable media of any preceding Example, wherein the operations further comprise: receiving a command to initiate playback at the second playback device; automatically grouping the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

Claims

Attorney Docket No 24-0201-PCTFortem Reference No. SNS.152WOCLAIMS1. A method performed by a media playback system comprising a plurality of playback devices, the method comprising:(a) playing back, via an audio transducer of a first playback device, an acoustic signal;(b) for each of the other playback devices: detecting, via one or more microphones of the other playback device, sound data while the first playback device plays back the acoustic signal; based at least in part on the detected sound data, obtaining an acoustic separation parameter that indicates an acoustic separation between the first playback device and the other playback device;(c) repeating steps (a) and (b) for each of the other playback devices, such that each of the other playback devices plays back an acoustic signal in turn while each of the remaining playback devices detects sound data; based on the obtained acoustic separation parameters, characterizing an acoustic topology of the plurality of playback devices; and based on the acoustic topology characterization, changing a state of at least one of the playback devices.

2. The method of claim 1, wherein characterizing the acoustic topology comprises, for each pair of playback devices, combining the two obtained acoustic separation parameters that indicate the acoustic separation between the pair of playback devices.

3. The method of any preceding claim, further comprising, prior to playing back the acoustic signal, performing a microphone check to confirm background noise level is below a predetermined threshold.

4. The method of any preceding claim, wherein each playback device stores a local copy of the acoustic topology characterization.

5. The method of any preceding claim, further comprising, for each of the other playback devices, and based at least in part on the detected sound data, obtaining a physical distance parameter.Attomey Docket No 24-0201-PCT Fortem Reference No. SNS.152WO6. The method of any preceding claim, further comprising, for each of the other playback devices, and based at least in part on the detected sound data, obtaining an angle-of- arrival parameter.

7. The method of any preceding claim wherein the acoustic signal comprises an inaudible signal.

8. The method of any preceding claim, wherein the acoustic signal comprises a plurality of sine sweeps.

9. The method of any preceding claim, wherein characterizing the acoustic topolog}’ comprises delineating acoustic separation between pairs of playback devices, including strong links (same acoustic pace), weak links (players are mutually audible, but in different acoustic space), and no link (players are mutually inaudible).

10. The method of any preceding claim, further comprising updating the acoustic topology characterization based on a detected change in the media playback system.

11. The method of any preceding claim, further comprising transmitting the acoustic topology characterization to at least one of the other playback devices.

12. The method of any preceding claim, further comprising: detecting, via one or more microphones of the first playback device, a voice input comprising a playback command; and causing the playback command to be applied to other playback devices within the same acoustic space as the first playback device.

13. The method of any preceding claim, further comprising: detecting, via one or more microphones of the first playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and other playback devices within the same acoustic space.

14. The method of any preceding claim, further comprising:Attorney Docket No 24-0201-PCTFortem Reference No. SNS.152WO receiving a command to initiate playback at the first playback device; and automatically grouping the first playback device with other playback devices within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

15. The method of any preceding claim, further comprising: determining that a portable playback device is within a predetermined acoustic separation distance of a home theatre bonded zone; automatically adding the portable playback device into the home theatre bonded zone; and synchronously playing back home theatre audio content via the home theatre bonded zone.

16. A method performed by a first playback device, the method comprising: transmitting, via an audio transducer of the first playback device, an acoustic signal; receiving, from a second playback device, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; and based on the acoustic separation parameter, causing a change in state of the first playback device or the second playback device.

17. The method of claim 16, wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

18. The method of any one of claims 16-17, further comprising, prior to transmitting the acoustic signal, receiving confirmation from the second playback device that a background noise level is below a predetermined threshold.

19. The method of any one of claims 16-18, further comprising obtaining a physical distance parameter based at least in part on the acoustic signal.

20. The method of any one of claims 16-19, wherein the acoustic separation parameter includes an angle-of-arrival parameter obtained by the second playback device.Attorney Docket No 24-0201-PCTFortem Reference No. SNS.152WO21. The method of any one of claims 16-20, wherein the acoustic signal comprises an inaudible signal.

22. The method of any one of claims 16-21, wherein the acoustic signal comprises a plurality of sine sweeps.

23. The method of any one of claims 16-22, further comprising: detecting, via one or more microphones of the first playback device, a voice input comprising a playback command; and causing the playback command to be applied to the second playback device, wherein the second playback device is in the same acoustic space as the first playback device.

24. The method of any one of claims 16-23, further comprising: detecting, via one or more microphones of the first playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.

25. The method of any one of claims 16-24, further comprising: receiving a command to initiate playback at the first playback device; automatically grouping the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

26. A method performed by a second playback device, the method comprising: detecting, via one or more microphones of the second playback device, an acoustic signal transmitted by a first playback device; determining, based on the detected acoustic signal, an acoustic separation parameter that characterizes an acoustic separation between the first playback device and the second playback device; based on the acoustic separation parameter, causing a change in stale of the first playback device or the second playback device.Attomey Docket No 24-0201-PCTFortem Reference No. SNS.152WO27. The method of claim 26. wherein the acoustic separation parameter indicates an acoustic attenuation of the acoustic signal from the first playback device to the second playback device.

28. The method of any one of claims 26-27, further comprising, prior to detecting the acoustic signal, performing a microphone check to confirm background noise level is below a predetermined threshold.

29. The method of any one of claims 26-28, further comprising obtaining a physical distance parameter based at least in part on the detected acoustic signal.

30. The method of any one of claims 26-29, further comprising obtaining an angle-of- arrival parameter based at least in part on the detected acoustic signal.

31. The method of any one of claims 26-30, wherein the acoustic signal comprises an inaudible signal.

32. The method of any one of claims 26-31 wherein the acoustic signal comprises a plurality of sine sweeps.

33. The method of any one of claims 26-32, further comprising: detecting, via the one or more microphones of the second playback device, a voice input comprising a playback command; and causing the playback command to be applied to the first playback device, wherein the first playback device is in the same acoustic space as the second playback device.

34. The method of any one of claims 26-33, further comprising: detecting, via the one or more microphones of the second playback device, a voice input; and providing feedback indicating detection of voice input via both the first playback device and the second playback device, wherein the first playback device and the second playback device are within the same acoustic space.Attorney Docket No 24-0201-PCTFortem Reference No. SNS.152WO35. The method of any one of claims 26-34, further comprising: receiving a command to initiate playback at the second playback device; automatically grouping the first playback device with the second playback device, wherein the first playback device and the second playback device are within the same acoustic space; and synchronously playing back audio via the grouped playback devices.

36. One or more tangible, non-transitory computer-readable media storing instructions that, when executed by one or more processors, cause one or more devices to perform operations comprising the method of any one of the preceding claims.

37. A playback device comprising: one or more microphones; one or more processors; and the one or more computer-readable media of claim 36.

38. A media playback system comprising: one or more playback devices having one or more microphones; one or more processors; and the one or more computer-readable media of claim 36.

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