# Patent

## Title
System and method for device playback calibration

## Abstract

Systems and methods are provided for device playback calibration. In one example, a calibration device with a microphone and signal processor may detect audio content rendered by a playback device. The calibration device may transmit the detected audio content to a processing unit configured to determine an equalization setting for optimal playback of the playback device based on the received detected audio content and a relative distance and direction between the playback device and the calibration device. The calibration device may further be configured to modulate the detected audio content before transmitting the detected audio content to the processing unit to accommodate for a limited frequency range of the processing unit. In this case, the processing unit may demodulate the received signal prior to determining the equalization setting. The processing unit may then transmit the determined equalization setting to the playback device according to a wireless communication protocol.

## Background
FIELD OF THE DISCLOSURE
The disclosure is related to consumer goods and, more particularly, to systems, products, features, services, and other items directed to media playback or some aspect thereof.
BACKGROUND
Technological advancements have increased the accessibility of music content, as well as other types of media, such as television content, movies, and interactive content. For example, a user can access audio, video, or both audio and video content over the internet through an online store, an internet radio station, a music service, a movie service, and so on, in addition to the more traditional avenues of accessing audio and video content. Beyond the increased accessibility of music content, demand for high quality rendering of music content for the user to enjoy anytime, everywhere has also increased.



BRIEF DESCRIPTION OF THE DRAWINGS
Features, aspects, and advantages of the presently disclosed technology are better understood with regard to the following description, appended claims, and accompanying drawings where:
FIG. 1A shows an illustration of an example system in which embodiments of the methods and apparatus disclosed herein can be implemented;
FIG. 1B shows an illustration of a second example system in which embodiments of the methods and apparatus disclosed herein can be implemented;
FIG. 2A shows an illustration of an example zone player having a built-in amplifier and speakers;
FIG. 2B shows an illustration of an example zone player having a built-in amplifier and connected to external speakers;
FIG. 2C shows an illustration of an example zone player connected to an A/V receiver and speakers;
FIG. 3 shows an illustration of an example controller;
FIG. 4 shows an internal functional block diagram of an example zone player;
FIG. 5 shows an internal functional block diagram of an example controller;
FIG. 6 shows an illustrative flow diagram of an example method for device playback calibration;
FIG. 7A shows an internal function block diagram of an example calibration microphone device;
FIG. 7B shows an illustrative flow diagram of an example method for device playback calibration by an example calibration microphone;
FIG. 8A shows an illustrative signal flow diagram of an example microphone device for playback calibration;
FIG. 8B shows a series of example audio content signals transmitted within the calibration microphone device; and
FIG. 8C shows a series of illustrative audio signals for device playback calibration in the time domain and the frequency domain.



In addition, the drawings are for the purpose of illustrating example embodiments, but it is understood that the present disclosure is not limited to the arrangements and instrumentality shown in the drawings.
DETAILED DESCRIPTION
I. Overview
Listening to audio content (e.g., music, talk radio, books, the audio from television, etc.) out loud may be a social activity that involves family, friends, or both. For example, in a household, people may play music out loud at parties and other social gatherings. In such an environment, people may wish to play the music in multiple listening zones simultaneously, such that the music in each listening zone may be synchronized, without audible echoes or glitches. Such an experience may be further enriched when people may browse audio sources, add a music track to a playback queue, learn more about a music track (such as track title or track artists), or view what music track is next in the playback queue. Listening to audio content out loud may also be an individual experience. For example, an individual may play music out loud for themselves in the morning before work, in the evening during dinner, or at other times throughout the day at home, work, or on the road. For these individual experiences, the individual may choose to either use headphones, or limit the out loud playback of audio content to a single zone or area.
In the case the user is listening to audio content out loud, the performance of an audio system may noticeably depend on an acoustic behavior of a room or area. As such, within each listening zone, the listening experience of the user may be further enriched by adjusting playback volumes and equalizations such that the listening experience is optimized at certain locations within the listening zone. For instance, in a home theater listening zone, the audio playback may be optimized specifically for people sitting on couch in front of a television and enjoying a movie. In another instance, in a porch or backyard listening zone, the audio playback may be optimized such that everyone in the vicinity may enjoy a comparable listening experience.
In one case, such a system may include audio players, often referred to as zone players or players, and controllers, which may also be a player. The controllers may be used to control the system, and may include capabilities for browsing and selecting audio content for playback, viewing and editing audio content in one or more playback queues, or grouping and ungrouping zone players into one or more listening zones, etc. In a sense, the system may operate as a distributed system such that each controller has full control over the entire system, and each player has the ability to play audio content from the either a same audio source or a different audio source as another player. The controllers may further be configured to operate as a calibration device for the system.
In an example embodiment of the present application, a system is provided. The system includes at least one playback device rendering audio content, a microphone configured to detect the rendered audio content from a first location relative to the at least one playback device, a signal processor configured to modulate the detected audio content with a modulation signal having a modulation frequency, and a processing unit in communication with the at least one playback device and signal processor. The processing unit is configured to receive the modulated audio content, demodulate the modulated audio content, and determine an equalization setting for the at least one playback device to render audio content based on an analysis of the demodulated audio content.
In another example embodiment of the present application, a device for playback calibration of at least one playback device is provided. The device includes a microphone configured to detect audio content rendered by the at least one playback device, and a signal processor configured to modulate the detected audio content for transmission to a processing unit configured to determine an equalization setting for the at least one playback device.
In yet another example embodiment of the present application, a method is provided for determining a first distance and direction of a playback device, causing the playback device to render audio content, receiving a first modulated version of the rendered audio content, and determining an equalization setting of the playback device based on the first modulated version of the rendered audio content, and the first distance and direction of the playback device.
With device playback calibration implemented on the system, as described above, the system may provide optimized playback of audio content by playback devices, thereby enriching the listening experience of users.
II. An Example Operating Environment
Referring now to the drawings, in which like numerals can refer to like parts throughout the figures, FIG. 1A shows an example system environment 100 in which one or more embodiments disclosed herein can be practiced or implemented.
By way of illustration, system environment 100 represents a home presently configured with multiple zones, though the home could have been configured with only one zone. Each zone in the home, for example, may represent a different room or space, such as an office, bathroom, bedroom, kitchen, dining room, family room, home theater room, utility or laundry room, and patio. A single zone might also include multiple rooms if so configured. One or more of zone players 102-124 are shown in each respective zone of the home. A zone player 102-124, also referred to as a playback device, multimedia unit, speaker, player, and so on, provides audio, video, and/or audiovisual output. Controller 130 provides control to system environment 100. Controller 130 may be fixed to a zone, or alternatively, mobile such that it can be moved about the zones. System environment 100 may also include more than one controller 130. System environment 100 illustrates an example whole house audio system, though it is understood that the technology described herein is not limited to its particular place of application or to an expansive system like a whole house audio system environment 100 of FIG. 1A.
FIG. 1B shows an example home theater environment 150 including the zone players 116, 118, and 120 as shown in FIG. 1A. The example home theater environment 150 may further include zone players 152, 154, 156 and a couch 158. As shown, the home theater environment 150 may be configured as a 5.1 surround sound system around a user sitting on the couch 158, such that zone player 116 may be configured to be the front left speaker, zone player 120 may be configured to be the center speaker, zone player 118 may be configured to be the front right speaker, zone player 154 may be configured to be the left rear speaker, zone player 156 may be configured to be the right rear speaker, and zone player 152 may be configured to be the low-frequency subwoofer.
A. Example Zone Players
FIGS. 2A, 2B, and 2C show example types of zone players. Zone players 200, 202, and 204 of FIGS. 2A, 2B, and 2C, respectively, can correspond to any of the zone players 102-124, and 152-156 of FIGS. 1A and 1B, for example. In some embodiments, audio is reproduced using only a single zone player, such as by a full-range player. In some embodiments, audio is reproduced using two or more zone players, such as by using a combination of full-range players or a combination of full-range and specialized players. In some embodiments, zone players 200-204 may also be referred to as a “smart speaker,” because they contain processing capabilities beyond the reproduction of audio, more of which is described below.
FIG. 2A illustrates zone player 200 that includes sound producing equipment 208 capable of reproducing full-range sound. The sound may come from an audio signal that is received and processed by zone player 200 over a wired or wireless data network. Sound producing equipment 208 includes one or more built-in amplifiers and one or more speakers. A built-in amplifier is described more below with respect to FIG. 4. A speaker or acoustic transducer might include, for example, any of a tweeter, a mid-range driver, a low-range driver, and a subwoofer. In some embodiments, zone player 200 can be statically or dynamically configured to play stereophonic audio, monaural audio, or both. In some embodiments, zone player 200 is configured to reproduce a subset of full-range sound, such as when zone player 200 is grouped with other zone players to play stereophonic audio, monaural audio, and/or surround audio or when the audio content received by zone player 200 is less than full-range.
FIG. 2B illustrates zone player 202 that includes a built-in amplifier to power a set of detached speakers 210. A detached speaker can include, for example, any type of loudspeaker. Zone player 202 may be configured to power one, two, or more separate loudspeakers. Zone player 202 may be configured to communicate an audio signal (e.g., right and left channel audio or more channels depending on its configuration) to the detached speakers 210 via a wired path.
FIG. 2C illustrates zone player 204 that does not include a built-in amplifier, but is configured to communicate an audio signal, received over a data network, to an audio (or “audio/video”) receiver 214 with built-in amplification.
Referring back to FIGS. 1A and 1B, in some embodiments, one, some, or all of the zone players 102-124, and 152-156 can retrieve audio directly from a source. For example, a zone player may contain a playlist or queue of audio items to be played. Each item in the queue may comprise a uniform resource identifier (URI) or some other identifier. The URI or identifier can point the zone player to the audio source. The source might be found on the internet (e.g., the cloud), locally from another device over data network 128, the controller 130, stored on the zone player itself, or from an audio source communicating directly to the zone player. In some embodiments, the zone player can reproduce the audio itself, send it to another zone player for reproduction, or both where the audio is played by the zone player and one or more additional zone players in synchrony. In some embodiments, the zone player can play a first audio content (or not play at all), while sending a second, different audio content to another zone player(s) for reproduction.
By way of illustration, SONOS, Inc. of Santa Barbara, Calif. presently offers for sale zone players referred to as a “PLAY:5,” “PLAY:3,” “CONNECT:AMP,” “CONNECT,” and “SUB.” Any other past, present, and/or future zone players can additionally or alternatively be used to implement the zone players of example embodiments disclosed herein. Additionally, it is understood that a zone player is not limited to the particular examples illustrated in FIGS. 2A, 2B, and 2C or to the SONOS product offerings. For example, a zone player might consist of a wired or wireless headphone. In yet another example, a zone player might include a sound bar for television. In yet another example, a zone player can include or interact with a docking station for an Apple iPodTM or similar device.
B. Example Controllers
FIG. 3 illustrates an example wireless controller 300 in docking station 302. By way of illustration, controller 300 can correspond to controlling device 130 of FIG. 1A. Docking station 302, if provided, may be used to charge a battery of controller 300. In some embodiments, controller 300 is provided with a touch screen 304 that allows a user to interact through touch with the controller 300, for example, to retrieve and navigate a playlist of audio items, control operations of one or more zone players, and provide overall control of the system configuration 100. In certain embodiments, any number of controllers can be used to control the system configuration 100. In some embodiments, there can be a limit set on the number of controllers that can control the system configuration 100. The controllers might be wireless like wireless controller 300 or wired to data network 128.
In some embodiments, if more than one controller is used in system environment 100, then each controller may be coordinated to display common content, and may all be dynamically updated to indicate changes made from a single controller. Coordination might happen, for instance, by a controller periodically requesting a state variable directly or indirectly from one or more zone players; the state variable may provide information about system 100, such as current zone group configuration, what is playing in one or more zones, volume levels, and other items of interest. The state variable may be passed around on data network 128 between zone players (and controllers, if so desired) as needed or as often as programmed.
In addition, an application running on any network-enabled portable device, such as an iPhoneTM, iPadTM, AndroidTM powered phone, or any other smart phone or network-enabled device can be used as controller 130. An application running on a laptop or desktop PC or Mac can also be used as controller 130. Such controllers may connect to system environment 100 through an interface with data network 128, a zone player, a wireless router, or using some other configured connection path. Example controllers offered by SONOS, Inc. of Santa Barbara, Calif. include a “Controller 200,” “Sonos CONTROL,” “Sonos® Controller for iPhone,” “Sonos® Controller for iPad,” “Sonos® Controller for Android, “Sonos® Controller for Mac or PC.”
C. Example Data Connection
Zone players 102-124, and 152-156 of FIGS. 1A and 1B are coupled directly or indirectly to a data network, such as data network 128. Controller 130 may also be coupled directly or indirectly to data network 128 or individual zone players. Data network 128 is represented by an octagon in the figure to stand out from other representative components. While data network 128 is shown in a single location, it is understood that such a network is distributed in and around system 100. Particularly, data network 128 can be a wired network, a wireless network, or a combination of both wired and wireless networks. In some embodiments, one or more of the zone players 102-124, and 152-156 are wirelessly coupled to data network 128 based on a proprietary mesh network. In some embodiments, one or more of the zone players 102-124, and 152-156 are wirelessly coupled to data network 128 using a non-mesh topology. In some embodiments, one or more of the zone players 102-124, and 152-156 are coupled via a wire to data network 128 using Ethernet or similar technology. In addition to the one or more zone players 102-124, and 152-156 connecting to data network 128, data network 128 can further allow access to a wide area network, such as the internet.
In some embodiments, connecting any of the zone players 102-124, and 152-156 or some other connecting device, to a broadband router, can create data network 128. Other zone players 102-124, and 152-156 can then be added wired or wirelessly to the data network 128. For example, a zone player (e.g., any of zone players 102-124, and 152-156) can be added to the system environment 100 or home theater environment 150 by simply pressing a button on the zone player itself (or perform some other action), which enables a connection to be made to data network 128. The broadband router can be connected to an Internet Service Provider (ISP), for example. The broadband router can be used to form another data network within the system configuration 100, which can be used in other applications (e.g., web surfing). Data network 128 can also be used in other applications, if so programmed. An example, second network may implement SonosNet protocol, developed by SONOS, Inc. of Santa Barbara. SonosNet represents a secure, AES-encrypted, peer-to-peer wireless mesh network. Alternatively, in certain embodiments, the data network 128 is the same network, such as a traditional wired or wireless network, used for other applications in the household.
D. Example Zone Configurations
A particular zone can contain one or more zone players. For example, the family room of FIG. 1A contains two zone players 106 and 108, while the kitchen is shown with one zone player 102. In another example, the home theater room contains additional zone players to play audio from a 5.1 channel or greater audio source (e.g., a movie encoded with 5.1 or greater audio channels). In some embodiments, one can position a zone player in a room or space and assign the zone player to a new or existing zone via controller 130. As such, zones may be created, combined with another zone, removed, and given a specific name (e.g., “Kitchen”), if so desired and programmed to do so with controller 130. Moreover, in some embodiments, zone configurations may be dynamically changed even after being configured using controller 130 or some other mechanism.
In some embodiments, if a zone contains two or more zone players, such as the two zone players 106 and 108 in the family room, then the two zone players 106 and 108 can be configured to play the same audio source in synchrony, or the two zone players 106 and 108 can be paired to play two separate sounds in left and right channels, for example. In other words, the stereo effects of a sound can be reproduced or enhanced through the two zone players 106 and 108, one for the left sound and the other for the right sound. In certain embodiments, paired zone players (also referred to as “bonded zone players”) can play audio in synchrony with other zone players in the same or different zones.
In some embodiments, two or more zone players can be sonically consolidated to form a single, consolidated zone player. A consolidated zone player (though made up of multiple, separate devices) can be configured to process and reproduce sound differently than an unconsolidated zone player or zone players that are paired, because a consolidated zone player will have additional speaker drivers from which sound can be passed. The consolidated zone player can further be paired with a single zone player or yet another consolidated zone player. Each playback device of a consolidated playback device is preferably set in a consolidated mode.
According to some embodiments, one can continue to do any of: group, consolidate, and pair zone players, for example, until a desired configuration is complete. The actions of grouping, consolidation, and pairing are preferably performed through a control interface, such as using controller 130, and not by physically connecting and re-connecting speaker wire, for example, to individual, discrete speakers to create different configurations. As such, certain embodiments described herein provide a more flexible and dynamic platform through which sound reproduction can be offered to the end-user.
E. Example Audio Sources
In some embodiments, each zone can play from the same audio source as another zone or each zone can play from a different audio source. For example, someone can be grilling on the patio and listening to jazz music via zone player 124, while someone is preparing food in the kitchen and listening to classical music via zone player 102. Further, someone can be in the office listening to the same jazz music via zone player 110 that is playing on the patio via zone player 124. In some embodiments, the jazz music played via zone players 110 and 124 is played in synchrony. Synchronizing playback amongst zones allows for someone to pass through zones while seamlessly (or substantially seamlessly) listening to the audio. Further, zones can be put into a “party mode” such that all associated zones will play audio in synchrony.
Sources of audio content to be played by zone players 102-124, and 152-156 are numerous. In some embodiments, music on a zone player itself may be accessed and a played. In some embodiments, music from a personal library stored on a computer or networked-attached storage (NAS) may be accessed via the data network 128 and played. In some embodiments, internet radio stations, shows, and podcasts can be accessed via the data network 128. Music or cloud services that let a user stream and/or download music and audio content can be accessed via the data network 128. Further, music can be obtained from traditional sources, such as a microphone, a turntable or CD player, via a line-in connection to a zone player, for example. Audio content can also be accessed using a different protocol, such as AirPlayTM, which is a wireless technology by Apple, Inc., for example. Audio content received from one or more sources can be shared amongst the zone players 102-124, and 152-156 via data network 128 and/or controller 130. The above-disclosed sources of audio content are referred to herein as network-based audio information sources. However, network-based audio information sources are not limited thereto.
In some embodiments, the example home theater zone players 116, 118, 120 are coupled to an audio information source such as a television 132. In some examples, the television 132 is used as a source of audio for the home theater zone players 116, 118, 120, while in other examples audio information from the television 132 can be shared with any of the zone players 102-124 in the audio system 100.
III. Zone Players
Referring now to FIG. 4, there is shown an example block diagram of a zone player 400 in accordance with an embodiment. Zone player 400 includes a network interface 402, a processor 408, a memory 410, an audio processing component 412, one or more modules 414, an audio amplifier 416, a microphone 422, and a speaker unit 418 coupled to the audio amplifier 416. FIG. 2A shows an example illustration of such a zone player. Other types of zone players may not include the speaker unit 418 (e.g., such as shown in FIG. 2B) or the audio amplifier 416 (e.g., such as shown in FIG. 2C). Further, it is contemplated that the zone player 400 can be integrated into another component. For example, the zone player 400 could be constructed as part of a television, lighting, or some other device for indoor or outdoor use.
In some embodiments, network interface 402 facilitates a data flow between zone player 400 and other devices on a data network 128. In some embodiments, in addition to getting audio from another zone player or device on data network 128, zone player 400 may access audio directly from the audio source, such as over a wide area network or on the local network. In some embodiments, the network interface 402 can further handle the address part of each packet so that it gets to the right destination or intercepts packets destined for the zone player 400. Accordingly, in certain embodiments, each of the packets includes an Internet Protocol (IP)-based source address as well as an IP-based destination address.
In some embodiments, network interface 402 can include one or both of a wireless interface 404 and a wired interface 406. The wireless interface 404, also referred to as an RF interface, provides network interface functions for the zone player 400 to wirelessly communicate with other devices (e.g., other zone player(s), speaker(s), receiver(s), component(s) associated with the data network 128, and so on) in accordance with a communication protocol (e.g., any of the wireless standards IEEE 802.11a, 802.11b, 802.11g, 802.11n, or 802.15). Wireless interface 404 may include one or more radios. To receive wireless signals and to provide the wireless signals to the wireless interface 404 and to transmit wireless signals, the zone player 400 includes one or more antennas 420. The wired interface 406 provides network interface functions for the zone player 400 to communicate over a wire with other devices in accordance with a communication protocol (e.g., IEEE 802.3). In some embodiments, a zone player includes both of the interfaces 404 and 406. In some embodiments, a zone player 400 includes only the wireless interface 404 or the wired interface 406.
In some embodiments, the processor 408 is a clock-driven electronic device that is configured to process input data according to instructions stored in memory 410. The memory 410 is data storage that can be loaded with one or more software module(s) 414, which can be executed by the processor 408 to achieve certain tasks. In the illustrated embodiment, the memory 410 is a tangible machine-readable medium storing instructions that can be executed by the processor 408. In some embodiments, a task might be for the zone player 400 to retrieve audio data from another zone player or a device on a network (e.g., using a URL or some other identifier). In some embodiments, a task might be for the zone player 400 to send audio data to another zone player or device on a network. In some embodiments, a task might be for the zone player 400 to synchronize playback of audio with one or more additional zone players. In some embodiments, a task might be to pair the zone player 400 with one or more zone players to create a multi-channel audio environment. Additional or alternative tasks can be achieved via the one or more software module(s) 414 and the processor 408.
The audio processing component 412 can include one or more digital-to-analog converters (DAC), an audio preprocessing component, an audio enhancement component or a digital signal processor, and so on. In some embodiments, the audio processing component 412 may be part of processor 408. In some embodiments, the audio that is retrieved via the network interface 402 or the microphone 422 is processed and/or intentionally altered by the audio processing component 412. Further, the audio processing component 412 can produce analog audio signals. The processed analog audio signals are then provided to the audio amplifier 416 for play back through speakers 418. In addition, the audio processing component 412 can include necessary circuitry to process analog or digital signals as inputs to play from zone player 400, send to another zone player on a network, or both play and send to another zone player on the network. An example input includes a line-in connection (e.g., an auto-detecting 3.5 mm audio line-in connection).
The audio amplifier 416 is a device(s) that amplifies audio signals to a level for driving one or more speakers 418. The one or more speakers 418 can include an individual transducer (e.g., a “driver”) or a complete speaker system that includes an enclosure including one or more drivers. A particular driver can be a subwoofer (for low frequencies), a mid-range driver (middle frequencies), and a tweeter (high frequencies), for example. An enclosure can be sealed or ported, for example. Each transducer may be driven by its own individual amplifier.
A commercial example, presently known as the PLAY:5, is a zone player with a built-in amplifier and speakers that is capable of retrieving audio directly from the source, such as on the internet or on the local network, for example. In particular, the PLAY:5 is a five-amp, five-driver speaker system that includes two tweeters, two mid-range drivers, and one woofer. When playing audio content via the PLAY:5, the left audio data of a track is sent out of the left tweeter and left mid-range driver, the right audio data of a track is sent out of the right tweeter and the right mid-range driver, and mono bass is sent out of the subwoofer. Further, both mid-range drivers and both tweeters have the same equalization (or substantially the same equalization). That is, they are both sent the same frequencies, just from different channels of audio. Audio from internet radio stations, online music and video services, downloaded music, analog audio inputs, television, DVD, and so on, can be played from the PLAY:5.
IV. Controller
Referring now to FIG. 5, there is shown an example block diagram for controller 500, which can correspond to the controlling device 130 in FIG. 1A. Controller 500 can be used to facilitate the control of multi-media applications, automation and others in a system. In particular, the controller 500 may be configured to facilitate a selection of a plurality of audio sources available on the network and enable control of one or more zone players (e.g., the zone players 102-124 in FIG. 1) through a wireless or wired network interface 508. According to one embodiment, the wireless communications is based on an industry standard (e.g., infrared, radio, wireless standards IEEE 802.11a, 802.11b 802.11g, 802.11n, or 802.15). Further, when a particular audio is being accessed via the controller 500 or being played via a zone player, a picture (e.g., album art) or any other data, associated with the audio and/or audio source can be transmitted from a zone player or other electronic device to controller 500 for display.
Controller 500 is provided with a screen 502 and an input interface 514 that allows a user to interact with the controller 500, for example, to navigate a playlist of many multimedia items and to control operations of one or more zone players. The input interface 514 may be coupled to a microphone 516 for capturing audio signals, such as audio content or voice commands as control inputs. The screen 502 on the controller 500 can be an LCD screen, for example. The screen 500 communicates with and is commanded by a screen driver 504 that is controlled by a microcontroller (e.g., a processor) 506. The memory 510 can be loaded with one or more application modules 512 that can be executed by the microcontroller 506 with or without a user input via the user interface 514 to achieve certain tasks. In some embodiments, an application module 512 is configured to facilitate grouping a number of selected zone players into a zone group and synchronizing the zone players for audio play back. In some embodiments, an application module 512 is configured to control the audio sounds (e.g., volume) of the zone players in a zone group. In operation, when the microcontroller 506 executes one or more of the application modules 512, the screen driver 504 generates control signals to drive the screen 502 to display an application specific user interface accordingly.
The controller 500 includes a network interface 508 that facilitates wired or wireless communication with a zone player. In some embodiments, the commands such as volume control and audio playback synchronization are sent via the network interface 508. In some embodiments, a saved zone group configuration is transmitted between a zone player and a controller via the network interface 508. The controller 500 can control one or more zone players, such as 102-124 of FIG. 1. There can be more than one controller for a particular system and each controller may share common information with another controller, or retrieve the common information from a zone player, if such a zone player stores configuration data (e.g., such as a state variable). Further, a controller can be integrated into a zone player.
It should be noted that other network-enabled devices such as an iPhone®, iPad® or any other smart phone or network-enabled device (e.g., a networked computer such as a PC or Mac®) can also be used as a controller to interact or control zone players in a particular environment. In some embodiments, a software application or upgrade can be downloaded onto a network-enabled device to perform the functions described herein.
In certain embodiments, a user can create a zone group (also referred to as a bonded zone) including at least two zone players from the controller 500. The zone players in the zone group can play audio in a synchronized fashion, such that all of the zone players in the zone group play back an identical audio source or a list of identical audio sources in a synchronized manner such that no (or substantially no) audible delays or hiccups could be heard. Similarly, in some embodiments, when a user increases the audio volume of the group from the controller 500, the signals or data of increasing the audio volume for the group are sent to one of the zone players and causes other zone players in the group to be increased together in volume.
A user via the controller 500 can group zone players into a zone group by activating a “Link Zones” or “Add Zone” soft button, or de-grouping a zone group by activating an “Unlink Zones” or “Drop Zone” button. For example, one mechanism for ‘joining’ zone players together for audio play back is to link a number of zone players together to form a group. To link a number of zone players together, a user can manually link each zone player or room one after the other. For example, assume that there is a multi-zone system that includes the following zones: Bathroom, Bedroom, Den, Dining Room, Family Room, and Foyer.
In certain embodiments, a user can link any number of the six zone players, for example, by starting with a single zone and then manually linking each zone to that zone.
In certain embodiments, a set of zones can be dynamically linked together using a command to create a zone scene or theme (subsequent to first creating the zone scene). For instance, a “Morning” zone scene command can link the Bedroom, Office, and Kitchen zones together in one action. Without this single command, the user would need to manually and individually link each zone. The single command might include a mouse click, a double mouse click, a button press, a gesture, or some other programmed action. Other kinds of zone scenes can be programmed.
In certain embodiments, a zone scene can be triggered based on time (e.g., an alarm clock function). For instance, a zone scene can be set to apply at 8:00 am. The system can link appropriate zones automatically, set specific music to play, and then stop the music after a defined duration. Although any particular zone can be triggered to an “On” or “Off” state based on time, for example, a zone scene enables any zone(s) linked to the scene to play a predefined audio (e.g., a favorable song, a predefined playlist) at a specific time and/or for a specific duration. If, for any reason, the scheduled music failed to be played (e.g., an empty playlist, no connection to a share, failed Universal Plug and Play (UPnP), no internet connection for an internet Radio station, and so on), a backup buzzer can be programmed to sound. The buzzer can include a sound file that is stored in a zone player, for example.
V. Playback Device Calibration
As mentioned above, the performance of an audio system may depend on the acoustic behaviors of a room or area in which the audio system is operating, and accordingly, the listening experience of a user may be further enriched by adjusting playback volumes and equalizations such that the listening experience is optimized at certain locations within the listening environment. In some audio systems, the user may be provided with varying degrees of control over the equalization (such as bass, treble, mid controls or subwoofer sub level controls) to achieve a desired equalization of the audio playback in the particular listening environment. As audio systems become more complex with more specialized speakers, the user may benefit from automatic or guided calibrations, after which the user may further adjust the settings to individual taste.
In one example, a calibration device with a microphone may be utilized for the automatic or guided calibrations of the audio system. In this case, the user may position the calibration device at different locations within a playback environment. At each of the positions, the audio system may render audio content for detection by the calibration device microphone at the location, and a computing device may be configured to then process the detected audio content and generate an optimized equalization setting for audio playback by the audio system playback in the playback environment. The calibration process using the calibration device with the microphone is discussed in further detail below in connection to FIG. 6.
FIG. 6 shows an illustrative block diagram of an example method 600 for device playback calibration using a calibration device, in accordance with at least some embodiments described herein. Method 600 shown in FIG. 6 presents an embodiment of a method that could be used in the environments 100 and 150 with the systems 200, 202, 204, 300, 400, and 500 for example, in communication with a device, such as devices illustrated in FIGS. 2-5, components of the devices, or a calibration device described in a following section. Method 600 may include one or more operations, functions, or actions as illustrated by one or more of blocks 602-616. As shown, blocks 602-608, 612, and 616 may involve actions, and blocks 610, and 614 may involve decisions. Although the blocks are illustrated in a sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation.
In addition, for the method 600 and other processes and methods disclosed herein, the flowchart shows functionality and operation of one possible implementation of present embodiments. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by a processor for implementing specific logical functions or steps in the process. The program code may be stored on any type of computer readable medium, for example, such as a storage device including a disk or hard drive. The computer readable medium may include non-transitory computer readable medium, for example, such as computer-readable media that stores data for short periods of time like register memory, processor cache and Random Access Memory (RAM). The computer readable medium may also include non-transitory media, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, for example, or a tangible storage device. In addition, for the method 600 and other processes and methods disclosed herein, each block in FIG. 6 may represent circuitry that is wired to perform the specific logical functions in the process.
At action block 602, the method 600 involves initiating calibration for a playback device or playback system. For purposes of illustration, a scenario may involve a user calibrating the audio system in the playback environment 150 shown in FIG. 1B. As shown, the audio system may include the left front channel speaker 116, the center channel speaker 120, the right front channel speaker 118, the rear left channel speaker 154, the rear right channel speaker 156, and the subwoofer 152. The playback environment as shown in FIG. 1B may also include the couch 158 where users may sit to enjoy a movie, and locations A, B, and C within the playback environment 150. In one example, calibration may be initiated for the entire audio system, a subgroup of playback devices in the system, such as front speakers 116, 118, and 120, or individual playback devices such as the subwoofer 152.
In one example, the user may initiate playback calibration via a controller, such as the controllers 130, 300, or 500 previously discussed. As mentioned above, the controller may be a smart phone, such as an iPhoneTM or AndroidTM powered phone, or any other or network-enabled device, such as an iPadTM. In another example, the controller may also be the calibration device with microphone discussed above. Further, due to a readily available user interface and processing capabilities, the smart phone or network-enabled device may also be configured to guide the user through the calibration process. For instance, a software application operating on a smart phone may provide a comprehensive calibration process, including prompting the user for necessary actions on the part of the user and providing audio content as test signals for detection. The smart phone may further be configured to perform the data processing and/or signal analysis on the detected audio content for playback calibration.
In one example, the device may prompt the user to initiate device calibration after each time the device or system has been disconnected, which may indicate that the device or system has relocated. In yet another example, the device may prompt the user to initiate device calibration after the user requests a change in preset equalization. For instance, the user may have previously selected a preset equalization for “Classical Music,” and has selected to change the preset equalization to “Jazz.” In this case, the user may be offered a choice between creating a new calibration setting for “Jazz” in the playback environment or having the system automatically adjust the equalization for “Jazz,” based on a previous calibration performed for “Classical Music.”
At action block 604, the method 600 involves locating or relocating the calibration device in the playback environment. In one example, the device calibration may be a guided process such that the user may be prompted to move the calibration device to a specific location within the playback environment. For example, referring to FIG. 1B, the calibration process may have been initiated to optimize the movie audio experience of viewers seated on the couch 158. In this example, the guided process may prompt the user to first locate the calibration device at location A, on the left end of the couch 158. In one case, various calibration processing steps may be performed while the calibration device is at location A, after which the user may be prompted to relocate the calibration device to location B, on the right end of the couch 158.
In another example, the user may be seated on the couch 158 at location C when initiating the calibration process. In one instance, the user may wish to calibrate the system to optimize the audio experience for someone sitting exactly where he/she is. In this instance, the calibration device may be configured to store the location of location C in the playback environment before proceeding with the playback calibration of the playback device or system.
At action block 606, the method 600 involves detecting audio content rendered by the playback device or system. In one example, the audio content rendered for playback calibration may be a favorite track selected by the user. In another example, the audio content may be a series of incremental frequencies spanning the audible frequency range. In one case, the audio content may be provided to the playback device by the calibration device.
In one case in which calibration was initiated for the entire audio system or a subgroup of playback devices in the system, each of the playback devices being calibrated may render audio content all at the same time for the calibration device microphone to detect from a predetermined location. In one example, calibration for a subgroup of playback devices 116, 120, and 118 may involve each playback device rendering audio content at the same time. In another case in which calibration was initiated for the entire audio system or a subgroup of playback devices in the system, audio content may be rendered sequentially by each playback device being calibrated, such that the calibration microphone may detect individually audio content rendered by each individual playback device from the predetermined location. In one example, calibration for the subgroup of playback device 116, 120, and 118 may involve playback device 116 rendering audio content first, followed by playback device 120 rendering audio content upon completion of the rendering of audio content by playback device 116, and further followed by playback device 118 rendering audio content upon completion of the rendering of audio content by playback device 120. In one instance, each of the playback devices 116, 120, and 118 may render the same audio content to provide a consistent frequency response spectrum for analysis.
At action block 608, the method 600 involves determining equalization adjustments based on an analysis of the detected audio content. In one example, the analysis of the detected audio content may involve evaluating the frequency response spectrum of the detected audio content. The evaluation of the frequency response spectrum of the detected audio content may include consideration for the capabilities and specializations of the playback device rendering the detected audio content. For example, the frequency response spectrum of detected audio content rendered by the subwoofer 152 may include stronger low-frequency responses and weaker high-frequency responses.
In addition to the capabilities and specializations of the playback device rendering the detected audio content, the evaluation of the frequency response spectrum of the detected audio content may also include considerations for a distance and direction of the playback device from the calibration device. For example, if the calibration device is located at location A, the calibration may anticipate stronger signal strength represented in the frequency response spectrum of detected audio content rendered by playback device 116 than that of the frequency spectrum of detected audio content rendered by playback device 118 by virtue of playback device 116 being closer to the calibration device at location A than playback device 118.
Based on the analyses of the frequency responses of the detected audio content, corresponding equalization adjustments for each playback device being calibrated may be determined. The equalization adjustments may indicate specific frequencies that are to be amplified or attenuated when being rendered by the corresponding playback device, such that the audio content rendered by the corresponding playback device after the adjustments will have a frequency response spectrum substantially matching a desired frequency response spectrum. In one case, the desired frequency response spectrum may be representative of a preset equalization setting, such as “Jazz” or “Classical Music,” as previously mentioned.
At decision block 610, the method 600 involves determining whether equalization adjustments should be made. As discussed above, the equalization adjustments may indicate frequency amplifications or attenuations by a corresponding playback device such that the frequency response spectrum of audio content rendered by the corresponding playback device will substantially match that of the desired frequency response spectrum. In one example, the determined equalization adjustments may indicate a number of frequencies or frequency ranges that are to be amplified, and another number of frequencies or frequency ranges that are to be attenuated. In this case, the method 600 may determine at decision block 610 that equalization adjustments are to be made, and may proceed to action block 612.
At action block 612, the method 600 involves adjusting the equalization settings of the one or more playback devices being calibrated. As previously discussed, a system or subgroup of playback device may be calibrated as a whole, or as individual playback devices. Accordingly, the adjustment of the equalization settings may be performed every time a playback device has rendered audio content for detection and analysis by the calibration device, or only after each playback device in the system or subgroup being calibrated has rendered audio content for detection and analysis.
In a further case, the equalization settings may be adjusted first individually, and then as a complete system or subgroup of playback devices. In other words, each playback device may first be calibrated independently, before fine-tuning of equalization settings for the playback devices in the system or subgroup as a whole, to account for potential acoustic interferences between the different playback devices in the system or subgroup.
Once the determined equalization adjustments have been made at the corresponding playback devices, the playback devices may render audio content for further detection and analysis as described before in reference to blocks 606, 608, and 610. The loop of blocks 606, 608, 610, and 612 may be continued until, at decision block 610, the method 600 determines that the frequency response spectrum of audio content rendered by the corresponding playback device substantially matches that of the desired frequency response, and accordingly that no further equalization adjustments are necessary. In this case, the method 600 may proceed to decision block 614.
At decision block 614, the method 600 involves determining whether the calibration device should be relocated to another location for further calibration. As discussed above, the calibration process may have been initiated to optimize the movie audio experience of viewers seated on the couch 158 of FIG. 1B. In this case, the calibration process may be performed at both location A, on the left side of the couch 158, and location B, on the right side of the couch 158. As such, upon completion of equalization adjustments of playback devices with the calibration device at location A, the method 600 may determine that audio content detection, frequency response spectrum analysis, and equalization adjustments still need to be performed with the calibration device at location B. In this case, the user may be prompted to relocate the calibration device to location B. In the case a smart phone is used as the calibration device, the user may be prompted via a user interface of the smart phone to relocate the calibration device. In another case, if only one calibration location is necessary, or once calibration steps have been performed at each of the calibration locations in the listening environment, then the calibration device does not need to be further relocated for calibration purposes. In this case, the method 600 may proceed to action block 616, where calibration is completed.
At action block 616, the method 600 involves completing the calibration process for the system, subgroup of playback devices, or individual playback device. In one case, the determined calibration settings for each calibrated playback device may be stored on the calibration device. In another case, the determined calibration settings for each calibrated playback device may be transmitted to each corresponding playback device for local storage. In one instance, the determined calibration settings may be transmitted to the playback device or system wirelessly according to a wireless communication protocol previously discussed.
In a real world application, the calibration process may take no longer than a few minutes and would not need to be repeated unless significant changes are made to the room arrangement. Further, as discussed previously, the calibration process is intended to provide the user with a good system equalization starting point, from which the user can make further manual adjustment according to personal preferences.
VI. Microphone Device for Playback Device Calibration
As discussed previously, a smart phone, such as an iPhoneTM or AndroidTM powered phone, or any other or network-enabled device, such as an iPadTM may be utilized as a calibration device due to the available user interface and data processing capabilities. In many cases, the smart phone or network-enabled device may also include a built-in microphone which may be configured to detect audio content rendered for the purpose of playback calibrations. Further, as applied towards a SONOS system as previously discussed, smart phones may already be utilized as controllers, and as such may further be configured to be used as a calibration device with minimal hassle or inconvenience to a user. In the following discussion, the term “smart phone” will be used to represent any network-enabled device capable of being utilized as a controller for an audio system.
In one case, the performance of the playback calibration method discussed above may depend on the consistency of a frequency responses and frequency sensitivities of a microphone used to detect audio content for calibration purposes. In one case, consistency of frequency responses and sensitivities may allow the playback calibration process to accommodate for particular audio content detection characteristics of the microphone. For instance, for optimal playback calibration of low-mid frequency audio rendering by a playback device, consistent frequency responses within the range of around 30 Hz to 1 kHz may be beneficial. In another instance, a consistent frequency response within the range of around 30 Hz to beyond 10 kHz may benefit playback calibration of the full audible frequency range rendering by a playback device. In some cases, however, built-in microphones on smart phones do not have consistent frequency responses and sensitivities for optimal playback calibration.
In one example, a calibration microphone having consistent frequency response and sensitivities within the desires frequency range may be provided for playback calibration. In one example, the calibration microphone may be coupled to the smart phone via the audio input jack of the smart phone. Smart phones, however, may be generally optimized for speech, and may accordingly be configured to filter out frequencies below 200 Hz, thereby filtering out a portion of the low-frequency audio content which may constitute an important component of popular music, and for which playback calibration may be applicable. On the other hand, the frequency response range of the smart phone audio input jack may extend up to around 10 kHz. In the application of low-mid audio frequency calibration, this leaves the frequency range of around 1 kHz to around 10 kHz unused and available. In one case, one or more frequencies within this available range may be suitably utilized, as will be discussed below.
FIG. 7A shows an illustrative block diagram of an example microphone device 700 which may be utilized as a calibration microphone when connected to a smart phone or controller as discussed above. As shown, the microphone device 700 includes a microphone 702, a signal processor 704, and a modulator 710.
In one example, the microphone 702 may be required to have a certain degree of frequency response and sensitivity consistency. In one case, as discussed above, the microphone 702 may be required to have a consistent frequency response within a range of 30 Hz to 1 kHz, such that audio content within the range of frequencies may be detected consistently.
FIG. 7B shows an illustrative flow diagram of an example method 750 for device playback calibration by an example calibration microphone device such as the microphone device 700 of FIG. 7A, in accordance with at least some embodiments described herein. As shown, method 750 presents an embodiment of a method that could be used in the environments 100 and 150 with the systems 200, 202, 204, 300, 400, and 500 for example, and performed by a device, such as the calibration device 700 shown in FIG. 7A. Method 750 may include one or more operations, functions, or actions as illustrated by one or more of blocks 752-758. Although the blocks are illustrated in a sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation.
At block 752, the method 750 involves detecting audio content rendered by the playback device being calibrated. Continuing with the example above relating to calibration of low-mid frequency range playback, the microphone 702 of the microphone device 700 may have a consistent, or at least predictable, frequency response within the frequency range of 30 Hz to 1 kHz. As such, the frequency components of the rendered audio content within the low-mid frequency range may be sufficiently detected by the microphone 702.
At block 754, the method 750 involves processing the detected audio content. Referring back to FIG. 7A, the signal processor 704 may be configured to receive the audio content detected by the microphone 702 and perform a degree of signal processing. In one case, the signal processor 704 may be configured to improve the signal-to-noise ratio of the detected audio content.
Also shown in FIG. 7A, the signal processor 704 may include a preamplifier 706 for amplifying the detected audio content and a low-pass filter 708 for removing high frequency noise components of the detected audio content, thereby improving the signal-to-noise ratio of the detected audio content. In one case, the detected audio content may include frequency components outside of the low-mid frequency range of 30 Hz to 1 kHz. In this case, the signal processor 704 may further be configured to filter out frequency components outside of the low-mid frequency range, as these frequency components may not be relevant for low-mid frequency playback calibration. Along similar lines, the low-pass filtering may also ensure that the frequency range between 1 kHz and 10 kHz remains unused, and available, as discussed above.
After the audio content has been detected by the microphone 702 and processed by the signal processor 704, the modulator 710 may be configured to modulate the audio content for output. As discussed previously, frequency response ranges for the audio input jacks of smart phones may be in the 200 Hz to 10 kHz range. Continuing with the low-mid frequency playback calibration example, the available frequency range of the audio input jack may be in the range of around 1 kHz to around 10 kHz. In this case, the detected and preprocessed mid-low audio frequency may then be modulated up into a frequency range within the available 1 kHz to 10 kHz range for transmission to the smart phone via the audio input jack. For instance, the 30 Hz to 1 kHz audio content may be modulated up into the 3 kHz to 5 kHz range, and provided to the smart phone via the audio input jack.
In one instance, the modulation may be performed by multiplying the preprocessed audio content by a modulation signal in the time-domain. In one case, the modulation frequency of the modulation signal may be 4 kHz, such that content in the pre-modulated 30 Hz to 1 kHz frequency spectrum may now exist within a pair of sidebands centered on 4 kHz. In other words, the audio content may now exist between 4 kHz and 5 kHz, as well as between 4 kHz and 3 kHz. The presence of both sidebands may be beneficial by way of providing signal duplicity, such that frequency response variation may be adequately corrected if necessary.
In one example, the modulation signal used for time-domain multiplication may be provided by a circuit of analog switches and operational amplifiers included on the microphone device 700. In another example, the modulation signal may be provided by the smart phone. As discussed above, the microphone device may be connected to the smart phone via the audio input jack on the smart phone. In many smart phones, the audio input jack may also be configured to be an audio output jack of the smart phone. As such, the smart phone may be configured to provide the modulation signal to the calibration microphone device via the same audio input/output jack.
In addition, depending on the playback frequency range being calibrated, different modulation frequencies may be appropriate. In such a case, the smart phone being utilized as the calibration device may further be configured to determine the proper modulation frequency for playback calibration for a certain frequency range, and accordingly provide the modulation signal having the determined modulation frequency for multiplying the audio content by. Along similar lines, different smart phones may have different input frequency response ranges. As such, the modulation frequency may further be determined based on the input frequency range of the smart phone. After the preprocessed audio content has been modulated, the modulated audio content may then be provided to the smart phone
At block 758, the method 700 may involve providing the modulated audio content for calibration. As indicated above, the modulated audio content may be provided to the smart phone via the audio input jack of the smart phone. The smart phone may be configured to, upon receiving the modulated audio content, further modulate the audio content to effectively de-modulate the audio content, thereby effectively generating the originally detected audio content. In the mid-low audio frequency example above, the smart phone may be configured to receive the detected audio content, which has been modulated up to the 3 kHz to 5 kHz range from the 30 Hz to 1 kHz range, and further modulate the received audio content back down to the 30 Hz to 1 kHz range. In one case, modulating the received audio content back down to the 30 Hz to 1 kHz range may be performed by multiplying the received audio content by the same 4 kHz modulation signal used to modulate the audio content previously. The smart phone may then proceed to execute the relevant playback calibration algorithms and processes discussed in the previous section.
VII. Example Signal Processing for Bass Playback Calibration
To further illustrate the application of a calibration microphone device such as the microphone device 700 of FIG. 7A, the following discussions in connection to FIGS. 8A to 8C provide an example of the signal processing by the calibration microphone for the calibration of low frequency “bass” audio content playback.
FIG. 8A shows an illustrative signal flow diagram of an example microphone device 800 for playback calibration. As shown, the calibration microphone device 800 includes a microphone 802, a signal processor 806, a modulator 808, an audio plug 810, and a power supply 812. In one example, the microphone 802, the signal processor 806, and the modulator 808 may be similar in structure and/or function to the microphone 702, the signal processor 704, and the modulator 710, respectively, of FIG. 7A. In one case, the audio plug 810 may be an audio plug capable of sending and receiving stereo audio signals.
In a further example, the power supply 812 may be configured to power the signal processor 806 and modulator 808. In one case, the calibration microphone device 800 may be powered by the smart phone via the audio plug 810. In this case, if the modulation signal is provided by the smart phone, as previously discussed, the power signal may be a rectified version of the modulation signal, and the power supply 812 may not be necessary.
Also shown in FIG. 8A are signal paths 803, 807, 809, and 811. Signal path 803 represents the transmission of the detected audio content from the microphone 802 to the signal processor 806. Signal path 807 represents the transmission of the preprocessed audio content from the signal processor 806 to the modulator 808. Signal path 809 represents the transmission of the modulated audio content from the modulator 808 to the audio plug 810.
Signal path 811 represents the transmission of the various signals from the smart phone to the calibration microphone device 800 via the audio plug 810. In one example, if the modulation signal is provided by the smart phone, signal path 811 may provide the transmission of the modulation signal to the modulator 808. In another example, as discussed above, the modulation signal from the smart phone may be rectified and used to power components. Further, signal path 811 may provide the transmission of any control inputs from the smart phone to control the calibration microphone device.
FIG. 8B shows a series of example audio content signals 830 illustrating the signals transmitted at each of the signal paths 803, 807, 809, and 811. The first in the series of example audio content signals 830 is an illustrative audio signal 837 detected by the microphone 802. As shown, the audio signal 837 may be in the form of a basic sine wave. The audio signal 837 may be transmitted from the microphone 802 to the signal processor 806 via signal path 803. For illustration purposes, the audio signal 837 in this example may be substantially the same after signal processing by signal processor 806 for an improved signal-to-noise ratio. As such, an audio signal similar to the audio signal 837 may then be transmitted to the modulator 808 via signal path 807.
The second in the series of example audio content signals 830 is an illustrative modulation signal 831 received from the smart phone via signal path 811. As shown, the modulation signal 831 may be in the form of square waves having a higher frequency than the audio signal 837. The third in the series of example audio content signals 830 is an illustrated modulated audio signal 839 produced by the multiplication of the audio signal 837 by the modulation signal 831. The modulation audio signal 839 may then be provided by the modulator 808 to the audio plug 810 via the signal path 809. As shown, the modulated audio signal 839 may be in the form of a square wave enveloped within a bipolar sine wave. A zoomed-in view 832 of the modulated audio signal 839 provides an illustration of the enveloped square wave.
As previously discussed, the modulated audio signal 839 may be the audio signal received by the smart phone via the input jack of the smart phone, and may further be demodulated and processed for playback calibration of the device rendering the audio signal 837 detected by the microphone 802.
FIG. 8C shows a series of illustrative audio signals for device playback calibration in the time domain and the frequency domain. The series of example audio content signals 830 shown and discussed above in connection to FIG. 8B provides an illustration of audio signals in the time domain. A different series of example audio content signals 860 is further provided as an illustration of the audio signals in the frequency domain.
As shown, the audio signal 837 may have a wavelength of 25 milliseconds, and therefore has a frequency of 40 Hz. The audio signal 837 may then be represented in the frequency domain as audio signal 867. Similarly, the modulation signal 831 may have a wavelength of 0.25 milliseconds, and therefore has a frequency of 4 kHz. The modulation signal 831 may then be represented in the frequency domain as modulation signal 861.
Further, the modulated audio signal 839 may be represented in the frequency domain as modulated audio signal 869. As shown, the, the resulting frequency domain modulated audio signal by convolving the audio signal 867 and modulation signal 861 results in the two side bands of 4.96 kHz and 4.04 kHz, centered on the modulation signal frequency of 4 kHz as previously discussed.
VIII. Conclusion
As discussed above, systems and methods are provided for device playback calibration such that the system may provide optimized playback of audio content by playback devices, thereby enriching the listening experience of users.
In an example embodiment of the present application, a system is provided. The system includes at least one playback device rendering audio content, a microphone configured to detect the rendered audio content from a first location relative to the at least one playback device, a signal processor configured to modulate the detected audio content with a modulation signal having a modulation frequency, and a processing unit in communication with the at least one playback device and signal processor. The processing unit is configured to receive the modulated audio content, demodulate the modulated audio content, and determine an equalization setting for the at least one playback device to render audio content based on an analysis of the demodulated audio content.
In another example embodiment of the present application, a device for playback calibration of at least one playback device is provided. The device includes a microphone configured to detect audio content rendered by the at least one playback device, and a signal processor configured to modulate the detected audio content for transmission to a processing unit configured to determine an equalization setting for the at least one playback device.
In yet another example embodiment of the present application, a method is provided for determining a first distance and direction of a playback device, causing the playback device to render audio content, receiving a first modulated version of the rendered audio content, and determining an equalization setting of the playback device based on the first modulated version of the rendered audio content, and the first distance and direction of the playback device.
The description discloses various example systems, methods, apparatus, and articles of manufacture including, among other components, firmware and/or software executed on hardware. However, such examples are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of these firmware, hardware, and/or software components could be embodied exclusively in hardware, exclusively in software, exclusively in firmware, or in any combination of hardware, software, and/or firmware. Accordingly, while the following describes example systems, methods, apparatus, and/or articles of manufacture, the examples provided are not the only way(s) to implement such systems, methods, apparatus, and/or articles of manufacture.
Additionally, reference herein to “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one example embodiment of the invention. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As such, the embodiments described herein, explicitly and implicitly understood by one skilled in the art, can be combined with other embodiments.
The specification is presented largely in terms of illustrative environments, systems, procedures, steps, logic blocks, processing, and other symbolic representations that directly or indirectly resemble the operations of data processing devices coupled to networks. These process descriptions and representations are typically used by those skilled in the art to most effectively convey the substance of their work to others skilled in the art. Numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, it is understood to those skilled in the art that certain embodiments of the present disclosure can be practiced without certain, specific details. In other instances, well known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the embodiments. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the forgoing description of embodiments.
When any of the appended claims are read to cover a purely software and/or firmware implementation, at least one of the elements in at least one example is hereby expressly defined to include a tangible medium such as a memory, DVD, CD, Blu-ray, and so on, storing the software and/or firmware.

## Claims

1. A system comprising:
a microphone configured to detect, from a first location relative to at least one playback device, audio content rendered by the at least one playback device;
a modulator configured to modulate the detected audio content with a modulation signal having a modulation frequency, wherein the modulation frequency is determined based on an input frequency range of a processing unit; and
the processing unit configured to:
receive the modulated audio content;
demodulate the modulated audio content; and
determine an equalization setting for the at least one playback device to render audio content based on an analysis of the demodulated audio content.

2. The system of claim 1, wherein the processing unit is configured to determine an equalization setting for the at least one playback device based on a frequency spectrum of the demodulated audio content.

3. The system of claim 1, wherein the modulation frequency is 4 kilohertz.

4. The system of claim 1, further comprising a signal processor configured to low-pass filter the detected audio content.

5. The system of claim 4, wherein the low-pass filtering of the detected audio content removes frequency components of the detected audio content above 1 kilohertz.

6. The system of claim 1, further comprising a portable calibration device comprising the microphone and the signal processor, wherein the calibration device is coupled to the processing unit via an audio input interface of the processing unit.

7. The system of claim 6, wherein the calibration device is powered by the processing unit via the audio input interface of the processing unit.

8. The system of claim 6, wherein the processing unit is configured to determine an equalization setting for the at least one playback device based on a distance and direction between the calibration device and the at least one playback device.

9. The system of claim 1, wherein the processing unit is further configured to transmit the determined equalization setting to the at least one playback device using a wireless communication protocol.

10. A device for playback calibration of at least one playback device comprising:
a microphone configured to detect audio content rendered by the at least one playback device; and
a modulator configured to modulate the detected audio content for transmission to a processing unit configured to determine an equalization setting for the at least one playback device, wherein the modulator is configured to modulate the detected audio content by multiplying the detected audio content with a modulation signal comprising a modulation frequency that is determined based on an input frequency range of the processing unit.

11. The device of claim 10, further comprising a signal processor configured to provide the modulation signal.

12. The device of claim 10, further comprising an audio interface configured to electrically couple the device to the processing unit and configured to receive the modulation signal.

13. The device of claim 10, further comprising a signal processor configured to amplify and low-pass filter the detected audio content.

14. A method performed by a computing device, the method comprising:
determining a first distance and direction of a playback device;
causing the playback device to render audio content;
transmitting a modulation signal comprising a modulation frequency, wherein the modulation frequency is determined based on an input frequency range of the computing device;
receiving a first modulated version of the rendered audio content; and
determining an equalization setting of the playback device based on the first modulated version of the rendered audio content, and the first distance and direction of the playback device.

15. The method of claim 14, further comprising:
causing a microphone device to detect the rendered audio content; and
causing the microphone device to modulate the detected audio content by multiplying the detected audio content with the modulation signal having the modulation frequency.

16. The method of claim 14, further comprising demodulating the first modulated version of the rendered audio content.

17. The method of claim 14, further comprising transmitting the determined equalization setting to the first playback device wirelessly.

18. The method of claim 14, further comprising:
determining a second distance and direction of the playback device;
causing the playback device to render the audio content;
receiving a second modulated version of the rendered audio content; and
determining an updated equalization setting of the playback device based on the determined equalization setting, the second modulated version of the rendered audio content, and the second distance and direction of the playback device.