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 theater, you can enjoy Dolby Atmos, Dolby Digital 7.1, or Dolby Digital 5.1 surround sound. HomePod mini does not support home theater surround sound, but you can stream audio from Apple TV to HomePod mini or a HomePod mini stereo pair using AirPlay.
Note: Home theater 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 theater, 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 theater 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 10 inches (25 centimeters) of a wall and as close to the center 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 4 feet (1.2 meters) apart from each other.