1. A first playback device comprising: one or more processors; a network interface; and tangible, non-transitory computer-readable memory comprising program instructions that, when executed by the one or more processors, cause the first playback device to: receive, via the network interface from a network device configured to control the first playback device and communicatively coupled to the first playback device over a local area network (LAN), (a) first control information identifying a first audio information source, wherein the first audio information source is accessible by the network device outside of the LAN; and (b) second control information identifying a second audio information source, wherein the second audio information source is accessible by the network device within the LAN; after receiving the first control information, (i) obtain, via the network interface from the first audio information source, first audio information; (ii) transmit, via the network interface of the first playback device to a second playback device, the first audio information, playback timing information associated with the first audio information, and device clock information of the first playback device; and (iii) play back the first audio information in synchrony with the second playback device by using the playback timing information associated with the first audio information and the device clock information of the first playback device to play back the first audio information, wherein the first and second playback devices remain independently clocked during synchronous playback of the first audio information; and after receiving the second control information, obtain, via the network interface from the second audio information source, second audio information.