When Sonos is working through SonosNet, the data flow works as follows:
Router -> BRIDGE )) Group Coordinator )) Rest of Group
The Group Coordinator is the room that you group all the other rooms to. This player acts as the chief player that will sync the data and then send it to every speaker in the group. In most cases, you want the Group Coordinator to be wired. This reduces the amount of interference that Sonos will have to combat before getting the data to the rest of the Sonos group.
I wasn't able to find much on this Group Coordinator topic searching support but it raises an interesting questions for my setup.
Since I have a Boost and several Plays (of various types) and two Zone Players all wired with the remaining units wireless would it make sense for me to select a wired component at the first member of any grouping I do to cut back on the wireless data transfer requirements?
If I have wireless and wired components in a group and drop the initial (Group Coordinator) from the group does Sonos select the second system I added to the group or a wired member of the group as the new Group Coordinator?
Did I miss any documentation on how this all works?
Best answer by Keith N
A handy way to determine what is the Group Coordinator is to look in the Rooms Tab and see what room is listed at the top of the group. If the Group Coordinator is removed from the group, Sonos will automatically handoff to another player in the group. The way it selects this player has changed a bit in the past (alphabetical by MAC address) and will likely continue to change as we make improvements to the software.
Let us know if you'd like us to build an FAQ or write up an in-depth post about the finer details of Group Coordinator. I'd be happy to get that ball rolling.