Unable to control the volume of HomePod with my Apple TV remote

When the Apple TV box is playing audio through the HomePod speakers, then it would receive volume adjustment commands from the Apple TV box, thus controlled through the Apple TV Remote (Siri Remote), using the Volume Up (+) and Volume Down (−) buttons. Same as any AirPlay speaker.

If the HomePod speakers are playing anything else as initiated on other devices than the Apple TV box, then volume control cannot be done through the Apple TV remote.

HomePod user guide - Apple Support

↳ Control audio with Siri on HomePod - Apple Support

↳ Use HomePod touch controls - Apple Support

Use HomePod with Apple TV 4K - HomePod user guide - Apple Support

Use HomePod for stereo and home theater sound on Apple TV - Apple Support

Set up home theater audio with HomePod or HomePod mini and Apple TV 4K - Apple Support

If the HomePod speakers are the default/primary audio output, then these speakers should be configured for the same HomeKit room name.

What is your model HomePod speakers? Identify your HomePod model - Apple Support

What is its software version?

What is your model Apple TV box? Identify your Apple TV model - Apple Support

What is its software version?

What is your model Apple TV remote? Identify your Apple TV remote - Apple Support

If you have verified to have set it up correctly and it still doesn’t work as it is supposed to, then please consider contacting the Apple Support staff for assistance. Contact Apple for support and service (phone numbers) or start your support request online (chat/​email/​callback).

That particular HomePod needs to be set as the default audio on the Apple TV 4K you’ve paired the Siri Remote to. Then any other HomePods (as well) that are playing in a group at the same time with this Homrpod can be controlled with that Siri Remote

You need:

• Apple TV 4K running the latest software.
• One HomePod or HomePod mini running the latest software.

Set Up:

With Apple TV: From the Home Screen on Apple TV, select Settings > Video and Audio > Audio Output. Select the HomePod or stereo pair that you want to use for home theater audio.

Set up home theater audio with HomePod or HomePod mini and Apple TV 4K - Apple Support