Techniques for Off-Net Synchrony Group Formation

A method comprising:

• receiving, from an external device, an audio stream at a first playback device via a first wireless network;
• playing back an audio output via an audio output interface at the first playback device, the audio output based on the audio stream;
• transmitting, by the first playback device, an indication of availability of the audio stream;
• detecting, by the first playback device, a request from a second playback device to play back the audio stream;
• establishing, by the first playback device, a second wireless network;
• detecting, by the first playback device, that the second playback device has joined the second wireless network;
• and
• transmitting, by the first playback device, the audio stream to the second playback device via the second wireless network.

A media playback system comprising:

• a first playback device comprising:
• one or more first processors;
• a first audio output interface operably connected to the one or more first processors and configured to output first audio;
• one or more first communication interfaces operably connected to the one or more first processors and configured to facilitate communication over at least one network;
• a first tangible, non-transitory computer-readable memory operably connected to the one or more first processors;
• and
• first program instructions stored on the first tangible, non-transitory computer-readable memory, wherein the first program instructions are executable by the one or more first processors such that the first playback device is configured to:
• receive an audio stream from an external device via a first wireless network;
• play back, via the first audio output interface, audio content based on the audio stream;
• while receiving the audio stream via the first wireless network, transmit an indication of availability of the audio stream;
• detect a request, from a second playback device, to play back the audio stream;
• establish a second wireless network;
• detect that the second playback device has joined the second wireless network;
• and
• transmit the audio stream to the second playback device via the second wireless network;
• and
• the second playback device comprising:
• one or more second processors;
• a second audio output interface operably connected to the one or more second processors and configured to output second audio;
• one or more second communication interfaces operably connected to the one or more second processors and configured to facilitate communication;
• a second tangible, non-transitory computer-readable memory operably connected to the one or more second processors;
• and
• second program instructions stored on the second tangible, non-transitory computer-readable memory, wherein the second program instructions are executable by the one or more second processors such that the second playback device is configured to:
• detect the indication of availability of the audio stream from the first playback device,
• transmit a response to the indication of availability of the audio stream to the first playback device,
• join the second wireless network, and
• receive the audio stream from the first playback device via the second wireless network.