Playing multiple AirPlay speakers from Apple TV

When Apple announced that AirPlay 2 will support multiple speakers, they did say the speakers will require a firmware update. I don’t remember if they said older ATVs will support it, or just the 4K model. Check with the maker of your speakers if the update is already available.

As you say, it's possible from iTunes on the Mac, but not from the Apple TV, no.

The iTunes video doesn't recognize the AirPlay speakers at all. It's either send audio and video to Apple TV or keep it on the computer. Primitive, maybe, but sort of understandable.

Not sure whether you have enough Apple TV's to realise, but whilst yes it will only send video and audio it to AirPlay speakers that can handle both, it will only do so to one speaker at a time.

Apple TV, by contrast, recognizes all the speakers but allows me to connect to only one at a time. Clicking on a new one, deselects the old one. But why? It doesn't really make sense.

In terms of audio only, I was always amazed at how well iTunes on my computer played to multiple speakers, on occasions we've had 7 or 8 airplay speakers on the go in what is quite a large house and they have always been perfectly in sync. Whilst I have no proof, I have always wondered if something more than simply sending out multiple streams was going on, such as some kind of sampling to determine the distance from the source to ensure perfect syncing. If so, it may well be that the Apple TV simply didn't have the power to do this.

Regardless of your sarcasm, you have never listened to "sound from a video or tv show throughout the house". The quoted text being your words from the question I was replying to.

As for AirPlay 2, I understand it only works with speakers that can connect via the home app and whilst I'm not certain, I have my doubts it will work with audio from a video.

Sorry just to correct that, it's not possible on the Mac either.