DCT
1:24-cv-00131
Sonos Inc v. Linkplay Technology Inc
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Sonos, Inc. (Delaware)
- Defendant: Linkplay Technology Inc. (Delaware); Linkplay Technology, Inc., Nanjing (China); Origin Acoustics, LLC (Delaware)
- Plaintiff’s Counsel: Potter Anderson & Corroon LLP
- Case Identification: 1:24-cv-00131, D. Del., 12/19/2024
- Venue Allegations: Venue is asserted based on Defendants Linkplay Technology Inc. and Origin Acoustics, LLC being incorporated in Delaware, and on allegations that all Defendants purposefully direct infringing activities into the district, including sales and distribution through online storefronts accessible to Delaware residents.
- Core Dispute: Plaintiff alleges that Defendants’ WiiM and Muzo networked multi-room audio systems, and associated Linkplay modules, infringe six patents related to controlling, synchronizing, and setting up networked playback devices.
- Technical Context: The technology concerns decentralized, networked home audio systems that enable users to play digital music from local or internet sources across multiple speakers, either independently or in synchronized groups.
- Key Procedural History: The complaint alleges a significant history preceding the lawsuit, including: (1) Plaintiff’s prior successful litigation against D&M Holdings, where a jury found the ’014 Patent willfully infringed; (2) a successful ITC investigation by Plaintiff against Google involving related patents; (3) extensive pre-litigation communications between Plaintiff and Defendant Linkplay beginning in January 2023, which culminated in a formal notice letter identifying all patents-in-suit in December 2023; and (4) prior reexamination proceedings for the ’014 and ’357 Patents, which confirmed the validity of the patents.
Case Timeline
| Date | Event |
|---|---|
| 2003-07-28 | Earliest Patent Priority Date (’014, ’532, ’357, ’498, ’023 Patents) |
| 2004-06-05 | Earliest Patent Priority Date (’883 Patent) |
| 2005-01-01 | Sonos launches first commercial products |
| 2009-08-04 | U.S. Patent No. 7,571,014 Issues |
| 2013-01-01 | Sonos begins "FILL YOUR HOME WITH MUSIC" campaign |
| 2013-03-19 | U.S. Patent No. 7,571,014 Reexamination Certificate Issues |
| 2014-01-01 | Sonos features tagline in Super Bowl commercial |
| 2015-01-01 | Linkplay launches "Muzo" networked multi-room audio system |
| 2015-10-20 | U.S. Patent No. 9,164,532 Issues |
| 2015-12-15 | U.S. Patent No. 9,213,357 Issues |
| 2018-12-04 | U.S. Patent No. 10,146,498 Issues |
| 2019-01-01 | Linkplay's "Muzo" system is discontinued in the United States |
| 2019-10-04 | U.S. Patent No. 9,213,357 Reexamination Certificate Issues |
| 2020-01-21 | U.S. Patent No. 10,541,883 Issues |
| 2020-12-01 | U.S. Patent No. 10,853,023 Issues |
| 2021-01-01 | Linkplay launches "WiiM" networked multi-room audio system |
| 2023-01-06 | First pre-litigation meeting between Sonos and Linkplay |
| 2023-02-15 | Conference call between Sonos and Linkplay |
| 2023-09-25 | Meeting in San Francisco between Sonos and Linkplay |
| 2023-12-11 | Sonos sends formal notice letter to Linkplay identifying patents-in-suit |
| 2024-05-01 | Sonos serves third-party subpoena on Origin Acoustics |
| 2024-12-19 | Second Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,571,014 - "Method and Apparatus for Controller Multimedia Players in a Multi-Zone System"
The Invention Explained
- Problem Addressed: The patent’s background describes conventional multi-zone audio systems as being based on a "centralized" device, "hard-wired" to passive audio players with dedicated speaker wire, which made it "difficult for [a conventional] system to accommodate the requirement of dynamically managing the ad hoc creation and deletion of groups" ('014 Patent, col. 1:34-2:4; Compl. ¶83).
- The Patented Solution: The invention is a system architecture comprising a networked "controller" and multiple independent "players" ('014 Patent, Fig. 1). The controller provides a user interface to dynamically form a "zone group" of two or more players for synchronous playback and to adjust the volume of the players within that group "individually or together" from anywhere on the network ('014 Patent, col. 7:25-43; Compl. ¶86).
- Technical Importance: This technology moved system intelligence from a central, hard-wired hub to a decentralized network of smart players and controllers, enabling flexible, software-defined multi-room audio experiences (Compl. ¶¶ 75, 87).
Key Claims at a Glance
- The complaint asserts independent claim 25 (Compl. ¶167).
- Claim 25 recites an apparatus for controlling players, comprising a screen, processor, and memory, where the processor executes code to perform operations including:
- displaying on a screen a first list showing at least available players;
- displaying a zone group including players from the available players when at least two of the available players are selected to form the zone group, wherein any one of the players in the group serves as a zone group head;
- synchronizing all players in the zone group in accordance with the zone group head; and
- adjusting a volume meter represented by an averaged value of audio volumes of the players in the group, wherein said adjusting of the volume meter includes changing a volume of each of the group of players synchronously in accordance with an adjustment made by a user.
- The complaint reserves the right to assert additional claims (Compl. ¶167).
U.S. Patent No. 9,164,532 - "Method and Apparatus for Displaying Zones in a Multi-Zone System"
The Invention Explained
- Problem Addressed: In networked audio systems where playback devices have independent clocks, small differences in playback timing or clock rates can cause the audio to get out of synchronization, which listeners perceive as an "echo effect" ('532 Patent, col. 2:9-11; Compl. ¶99). This is exacerbated by variable delays in transferring audio information over the network ('532 Patent, col. 2:12-17).
- The Patented Solution: The invention describes forming a "synchrony group" where a controller configures a first "zone player" (master) to transmit "audio content, playback timing for the audio content, and device clock information" to a second "zone player" (slave) over a local network ('532 Patent, Claim 34). This allows the second player to play back the audio in synchrony with the first, even though both players "remain independently clocked" ('532 Patent, Claim 34; Compl. ¶¶ 102, 104).
- Technical Importance: This technology provided a method for achieving reliable, synchronized audio playback across multiple devices with independent clocks on a potentially unreliable data network (Compl. ¶101).
Key Claims at a Glance
- The complaint asserts independent claim 34 (Compl. ¶179).
- Claim 34 recites a controller device with a processor and memory executing instructions to perform a method comprising:
- receiving a command at the controller device to form a synchrony group comprising a first zone player and a second zone player;
- in response to receiving the command, configuring the synchrony group, wherein configuring comprises configuring, over a Local Area Network (LAN), the first zone player to (a) transmit audio content, playback timing for the audio content, and device clock information to the second zone player and (b) play back the audio content in synchrony with the second zone player...; and
- after the controller device has configured the synchrony group, the controller device receiving status information over the LAN from at least one of the first or second zone players indicating that the first and second zone players in the synchrony group are configured to playback audio in synchrony with each other.
- The complaint reserves the right to assert additional claims (Compl. ¶179).
U.S. Patent No. 9,213,357 - "Obtaining Content from Remote Source for Playback"
Technology Synopsis
The patent is directed to synchronizing playback devices when the audio source is outside the local network (LAN), such as an internet streaming service (Compl. ¶¶ 112, 116; ’357 Patent, Claim 9). A first playback device obtains the audio from the remote source and transmits the audio information, along with playback timing and device clock information, to a second playback device over the LAN for synchronous playback ('357 Patent, Claim 9).
Asserted Claims
The complaint provides a claim chart for independent claim 9 (Compl. ¶191).
Accused Features
The accused functionality is the ability of the WiiM and Muzo systems to group players to synchronously play audio streamed from an Internet-based music service, where one player acts as the "master" for the group (Compl. ¶191, p. 69).
U.S. Patent No. 10,541,883 - "Playback Device Connection"
Technology Synopsis
The patent addresses simplifying the process of connecting a new consumer electronic device to a secure wireless network, which traditionally required technical knowledge of networking and security settings ('883 Patent, col. 1:37-49; Compl. ¶¶ 123-124). The invention involves the new playback device entering a setup mode and establishing an "initial communication path" with a computing device (e.g., a phone) that does not traverse the secure network's access point; this direct path is used to receive the "network configuration parameters" needed to join the secure WLAN ('883 Patent, Claim 1; Compl. ¶130).
Asserted Claims
The complaint provides a claim chart for independent claim 1 (Compl. ¶202).
Accused Features
The accused feature is the setup process for WiiM players, where the WiiM Home app on a user's device detects the new player (e.g., via Bluetooth) and transfers Wi-Fi credentials over this direct, initial communication path (Compl. ¶202, pp. 76-77).
U.S. Patent No. 10,853,023 - "Networked Playback Device"
Technology Synopsis
The patent describes a technology for intelligent, automatic source-switching on a playback device, addressing the cumbersome user actions previously required to switch inputs ('023 Patent, col. 2:37-56; Compl. ¶138). The device can be "armed" so that detecting a signal on a line-in connector automatically "preempts" playback of a second media content (e.g., streaming music), and when the line-in signal ceases, the device can "rearm" itself to auto-play again upon subsequent signal detection ('023 Patent, Claim 1; Compl. ¶146).
Asserted Claims
The complaint provides a claim chart for independent claim 1 (Compl. ¶214).
Accused Features
The accused feature is the "auto-sensing" capability of WiiM players, which "automatically play[s] audio from the connected input as soon as a signal is detected, regardless of the device’s current state or standby mode" (Compl. ¶150, ¶214, p. 87).
U.S. Patent No. 10,146,498 - "Disengaging and Engaging Zone Players"
Technology Synopsis
This patent addresses the dynamic reallocation of a zone player from one synchrony group to another ('498 Patent, Abstract; Compl. ¶153). A first zone player in a first synchrony group receives control information directing it to disengage from its current group and join a second synchrony group with a third player; it then receives audio information from that third player for synchronous playback ('498 Patent, Claim 1; Compl. ¶159).
Asserted Claims
The complaint provides a claim chart for independent claim 8, a system claim (Compl. ¶226).
Accused Features
The accused feature is the ability of the Linkplay system, via the WiiM or Muzo controller app, to receive user commands to move a player from one group to another, causing it to disengage from the first group and synchronize its playback with the new group (Compl. ¶226, p. 96).
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are the "WiiM System," the "Muzo System," and "Linkplay modules" (Compl. ¶¶ 11, 12, 31). The WiiM System includes a line of networked multi-room audio players (WiiM Amp, WiiM Pro, WiiM Mini, etc.) and the WiiM Home app for control (Compl. ¶12). The Muzo System included the "Cobblestone" player and the Muzo app (Compl. ¶11).
Functionality and Market Context
The accused products are networked audio devices that stream music and allow users to form groups of devices for synchronized, multi-room playback (Compl. ¶¶ 12, 95). The complaint alleges that these systems compete directly with Plaintiff’s products, often at a "significantly lower price," and that they were designed to "shamelessly copy" Plaintiff's technology, functionality, and design (Compl. ¶¶ 13, 23, 26). The complaint includes a visual comparison showing the physical similarity between the WiiM Pro and the Sonos Port, which an article described as "practically a carbon copy" (Compl. ¶23, p. 8). Another visual provides a side-by-side comparison of the WiiM Home app and the Sonos app, illustrating similarities in the user interface for browsing music services and managing devices (Compl. ¶28, p. 11).
IV. Analysis of Infringement Allegations
’014 Patent Infringement Allegations
| Claim Element (from Independent Claim 25) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An apparatus for controlling a plurality of players, the apparatus comprising: [a screen, a screen driver, an input interface, a network interface, a memory, and a processor] | The accused "Linkplay controller" (e.g., a smartphone running the WiiM Home app) comprises these standard hardware components. | ¶167, pp. 50 | col. 7:4-18 |
| [the processor executing the code...] displaying on a screen a first list showing at least available players; | The WiiM Home app displays a list of available Linkplay players on a "Devices page." The complaint provides a screenshot showing this list of devices. (Compl. ¶167, p. 51). | ¶167, p. 51 | col. 7:34-37 |
| displaying a zone group including players from the available players when at least two of the available players are selected to form the zone group, wherein any one of the players in the group serves as a zone group head; | The controller app allows a user to select two or more Linkplay players to form a "group" for synchronous playback, where one player is designated as the "master" of the group. | ¶167, p. 52 | col. 7:38-43 |
| synchronizing all players in the zone group in accordance with the zone group head; and | The controller app causes the players in the group to engage in synchronous playback in accordance with the "master" player. | ¶167, p. 53 | col. 5:24-38 |
| adjusting a volume meter represented by an averaged value of audio volumes of the players in the group...changing a volume of each of the group of players synchronously... | The controller app displays a "group volume" meter that, when adjusted by a user, changes the volume of each player in the group synchronously. Screenshots are provided to illustrate this feature. (Compl. ¶167, p. 54). | ¶167, pp. 53-54 | col. 8:1-12 |
- Identified Points of Contention:
- Scope Questions: Does Defendants' "master/slave" architecture, where one player controls others, meet the definition of a "zone group head" as recited in the claim? The claim language "serves as a zone group head" may be subject to interpretation regarding the specific functions required.
- Technical Questions: What is the technical basis for the allegation that the accused "group volume" is "represented by an averaged value" of the individual player volumes? Infringement of this element may depend on evidence showing a specific mathematical averaging function, rather than a simple relative offset control.
’532 Patent Infringement Allegations
| Claim Element (from Independent Claim 34) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A controller device comprising: [processors and memory]...cause the controller device to perform a method comprising: | The accused Linkplay controller (e.g., a smartphone with the WiiM app) contains the recited hardware and software to perform the claimed method steps. | ¶179, pp. 59-60 | col. 5:15-18 |
| receiving a command at the controller device to form a synchrony group comprising a first zone player and a second zone player; | The WiiM Home app is programmed to receive user input to form a "group" of two or more players. A series of screenshots in the complaint illustrates a user selecting an additional player to form a group. (Compl. ¶179, p. 60). | ¶179, p. 60 | col. 5:4-10 |
| in response...configuring the synchrony group...the first zone player to (a) transmit audio content, playback timing for the audio content, and device clock information to the second zone player and (b) play back the audio content in synchrony... | In response to the user command, the controller communicates with the players over Wi-Fi (a LAN) to configure the group, designating one as a "master" to transmit audio, timing, and clock information to the "slave" players for synchronous playback. | ¶179, pp. 61-62 | col. 31:21-35 |
| wherein the first and second zone players remain independently clocked while playing the audio content in synchrony... | The complaint alleges that each Linkplay player continues to operate with its own clock, citing forum posts from a WiiM employee discussing compensation for "clock discrepancy" and "managing clock skew." | ¶179, p. 62 | col. 31:21-28 |
| after the controller device has configured the synchrony group, the controller device receiving status information over the LAN...indicating that the first and second zone players...are configured to playback audio in synchrony... | The controller app is alleged to receive status messages over the LAN indicating that the players have been successfully configured into a synchrony group. A screenshot of the app's device list shows the grouped players. (Compl. ¶179, p. 63). | ¶179, pp. 62-63 | col. 6:27-31 |
- Identified Points of Contention:
- Technical Questions: What specific "device clock information" is transmitted between accused players? The infringement theory relies in part on statements by a "WiiM employee" in a public forum, the technical accuracy and completeness of which may be a point of dispute (Compl. ¶179, p. 62).
- Scope Questions: Does the accused controller app perform the step of "configuring the synchrony group," or does it merely send an instruction to the players, which then configure themselves? The claim requires the controller to perform the configuring step, creating a potential dispute over where the claimed function is performed.
V. Key Claim Terms for Construction
The Term: "zone group head" ('014 Patent, Claim 25)
- Context and Importance: This term is foundational to the patent's model of group control and synchronization. The infringement analysis may turn on whether the functions of the Defendants' designated "master" player in a group are coextensive with the functions of the claimed "zone group head."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim itself provides a broad functional definition: "wherein any one of the players in the group serves as a zone group head" ('014 Patent, col. 7:40-41), which suggests any player designated to lead the group could meet the definition.
- Evidence for a Narrower Interpretation: The specification describes a zone group head as potentially being the source of the audio for the group ('014 Patent, col. 5:24-28: "the zone player 11(n) will transmit the audio information...to the selected zone players"). A defendant may argue this implies a specific network topology or function that its "master" player does not perform.
The Term: "configuring the synchrony group" ('532 Patent, Claim 34)
- Context and Importance: This term defines an action performed by the claimed "controller device." The central question is whether the accused controller application performs this action itself, or if it merely instructs the playback devices to perform the configuration.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states that a user, via the user interface module, can "enable a zone player...to join a synchrony group" ('532 Patent, col. 6:26-29). This suggests the controller's role is to facilitate or enable the configuration, which could be interpreted broadly to include sending the necessary commands for the players to act.
- Evidence for a Narrower Interpretation: The claim language recites "the controller device...configuring the synchrony group, wherein configuring...comprises configuring...the first zone player to (a) transmit..." ('532 Patent, Claim 34). This language could be read to require the controller to directly perform the configuration of the first zone player, rather than merely ordering the player to configure itself.
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement by Defendants promoting and instructing users on how to use the accused features, such as grouping players for multi-room audio and using the app for control (Compl. ¶¶ 168, 180). It also alleges contributory infringement by providing the WiiM and Muzo apps, which it characterizes as material components with no substantial non-infringing use that are especially adapted for use in an infringing manner (Compl. ¶¶ 169, 181).
- Willful Infringement: The complaint alleges willfulness based on both pre- and post-suit knowledge. Pre-suit knowledge is alleged based on Defendants' alleged copying of Sonos products, awareness of Sonos's market position and patent portfolio, media coverage of prior Sonos litigation involving the '014 Patent, and direct pre-litigation communications and a formal notice letter that identified all patents-in-suit (Compl. ¶¶ 32-51, 170).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of claim construction: can the terms "zone group head" and "configuring the synchrony group," which are rooted in the patents' specific architecture, be construed to cover the functions of the "master" player and the controller application in the Defendants' accused master/slave system? The outcome may depend on whether these terms are interpreted functionally or as requiring a more specific technical implementation.
- A key evidentiary question will be one of technical operation: what evidence will demonstrate that the accused systems perform the specific technical steps of the claims, such as adjusting group volume based on an "averaged value" and transmitting "device clock information" between players to manage synchronization? The analysis will likely focus on the precise software and network protocol implementation of the accused features.
- Given the detailed allegations of pre-suit meetings, a formal notice letter, and prior litigation involving the '014 patent, a central question for trial will be willfulness. Should infringement be found, the extensive factual predicate laid out in the complaint raises a significant question of whether Defendants' conduct was egregious enough to warrant enhanced damages.