I own 3 Apple TV's. The selection of Audio Output works on 2 of them ... but I can't even get it to show up on the 3rd. One of the ATV's actually asked me to select a audio output speaker (selected HomePod and worked just fine). The second one did not ask, but I was able to select it in the menu. The 3rd never asked and it doesn't even show up as an option. NOTE: All 3 ATV's and HomePods are setup in the "Home App" and each speaker is in the correct room. I did a complete factory re-set and made sure all hardware is on the latest ATV OS and firmware. I find it very strange that it works fine on 2 units ... but not on the 3rd (all the same versions of hardware). Hmmmm - What's going on? Tim