Use HomePod with Apple TV 4K
If you have an Apple TV 4K and HomePod (2018), you can create an immersive experience with a single HomePod or a stereo pair. When you set up home theatre, you can enjoy Dolby Atmos, Dolby Digital 7.1 or Dolby Digital 5.1 surround sound. HomePod mini does not support home theatre surround sound, but you can stream audio from Apple TV to HomePod mini or a HomePod mini stereo pair using AirPlay.
Note: Home theatre requires Apple TV 4K with tvOS 14.2 or later. For more information about setting up Apple TV see the Apple TV User Guide.
To set up home theatre, you need an iPhone or iPod touch with iOS 14.2 or later, or an iPad with iPadOS 14.2 or later. Make sure that Apple TV is assigned to the same room as HomePod in the Home app.
Alternatively, you can set up the home theatre on your Apple TV 4K with tvOS 14.2 or later (for details see the Apple TV User Guide).
In the Home app on your iOS or iPadOS device touch and hold Apple TV.
Tap Default Audio Output, then tap the room with your HomePod or HomePod stereo pair.
Note: This setting routes all sound, including navigation clicks, from Apple TV to your HomePod.
For the best surround sound place HomePod within 25 centimetres of a wall and as close to the centre of your TV as possible. If you use a HomePod stereo pair place the speakers on either side of the TV. For optimal surround sound, the HomePod speakers should be about 1.2 metres apart from each other.