1. A method comprising: periodically receiving, by a playback device over a local network, a message transmitted from a source device, wherein the message comprises clock information of the source device; computing, by the playback device based on the message, a time differential between a clock of the playback device and a clock of the source device; receiving, by the playback device over a local network, a command to cease playback of a first song received from the source device and played by the playback device, wherein the command to cease playback includes a time indicating when to cease playback of the first song, and wherein the time indicating when to cease playback of the first song is based on the clock of the source device; computing, by the playback device, a specified time to cease playback of the first song, wherein the specified time is based on the time differential and the time indicating when to cease playback of the audio information; and ceasing, by the playback device, playback of the first song at the specified time.