1. A method for synchronizing audio playback of a plurality of separate audio playing devices with one another, the method comprising: receiving, by a playback device, an audio stream including a plurality of frames from a source device over a local network, wherein each frame of the plurality of frames is associated with audio information and a time indicating when to play the audio information of the respective frame, wherein the time is based on a clock of the source device, which is independent of a clock of the playback device; periodically receiving, by the playback device over the local network, a message transmitted from the source device, the message separate from the audio stream and including clock information of the source device; computing, by the playback device, a time differential between the clock of the source device and the clock of the playback device based on the message; converting, by the playback device and for each frame of the plurality of frames, a computed output time of the audio information for each respective frame based on both the time associated with each respective frame and the computed time differential.