- Apple TV Gen 4
- MBP early 2013 with Sierra (10.12.6)
I'm unable to make the MBP switch from internal speakers to Great Room, the name of my Apple TV. I click Great Room, and after a moment of silence it switches back to internal speakers. Both the MBP and the Apple TV are connected via Ethernet to a Time Capsule. They are both on the same subnet.
I can use my more recent MBP to send its audio to Great Room (using WiFi). And while connected this way, I can return to the ethernet-connected MBP, try to switch to Great Room, which knocks my newer MBP off, but still, after a moment, the old MBP switches back to internal speakers. I conclude, then, that the Apple TV and my new MBP are configured properly but the old MBP is not.
It used to work fine until the other day when I rearranged and reconnected the router and the MBP, but as far as I can tell all other connectivity is intact.
There are several system interfaces that offer "Great Room" as an option. Right-clicking the audio volume menu icon; clicking the AirPlay menu icon; the Sound System Preference panel; the Display System Preference panel. I don't know if they all accomplish the same thing, or if one is necessary for the other, or just what.
UPDATE: I am able to send iTunes audio to the Apple TV. (iTunes has yet another interface for sound routing, in the iTunes toolbar). However, I'm still unable to use any of the other four interfaces to switch from internal speakers to AirPlay.