Connecting a HomePod to your Apple TV is very easy, but it's not a great solution for home theater audio.
www.lifewire.com
It can be done, but keep in mind that the HomePod is going to provide 2 channel sound only. That's similar to lower priced sound bars, but not $400-$500 sound bars that typically provide 5.1 channels.
OK. That article is ignorant garbage. (Sorry, but it's true!)
Here's what you need to do:
https://support.apple.com/en-us/HT210526
Note the steps.
First calibrate your HomePod with your aTV and TV (using your iPhone). The iPhone needs to be VERY close to the TV (like less than a foot away).
NEXT (and this the part they don't really tell you, just a sneaky little last line in the article) do you have Content Matching on?
Learn how to turn on frame rate and dynamic range matching.
support.apple.com
This means: when you play a movie does the TV screen switch to 24Hz? If so, then you need to force your aTV "preferred frame rate" to 24 Hz. Go to Settings>Displays and Audio and select the Display Resolution there is a 'more options' option on the menu: click that and one of the options is 1080p 24Hz.
Now repeat calibration all over again at 24Hz!
If you use other modes (maybe HDR? maybe 50Hz?) you have to repeat calibration for every mode!!! Ridiculous, I know...
(Remember, after all this is done, to set Settings>Displays and Audio > Display Resolution back to 1080p@60Hz or whatever you were using.)
OK, so now you have calibrated your HomePod at every content mode.
NOW bring up aTV Control Center (long press on the aTV remote Home button). Go down to the AirPlay logo at the bottom of the screen and click it. You should get a list of all the audio devices you could be sending audio to. What you want is to to choose your HomePod (s) as being ticked while the TV audio is also still ticked, so that audio is being sent to multiple devices.
Look at this image (Control Center doesn't look exactly like this, but close enough)
Two points
- the circle next to a speaker name means the speaker can be chosen SIMULTANEOUSLY with another speaker.
- so you want to have both Apple TV, the top one called Living Room (the HDMI TV sound) and the HomePod, ie the bottom one, both selected with a tick next to both of them.
Now you should get audio that is in sync, but coming out of both your TV in front of you and the HomePod. IMHO it works better with the HomePod(s) behind you -- that way the whole room is filled with even sound volume, and the effects sounds, which is what HomePod really brings out, are mostly low frequency so not placed anywhere in space.
If you did not calibrate then the TV audio will be out of sync with the HomePod audio --very irritating.
If you only calibrated for, say, 60Hz, then it will appear to work with some content, like TV content, but be out of syc for other content like movies. Even worse because it seems to randomly work or not work...