I find that hard to believe, but I'm willing to be wrong. My Apple TV HD is in a cabinet with solid sides and doors (3/4" MDF). The television is wall mounted a

I find that hard to believe, but I'm willing to be wrong. My Apple TV HD is in a cabinet with solid sides and doors (3/4" MDF). The television is wall mounted above it, outside the cabinet, and maybe 12" behind the Apple TV. And yet the Siri Remote controls the volume on the TV. I'm pretty sure it's using IR from the remote to the television to control the television's volume. I guess there's some small chance the volume is being controlled with HDMI ARC, although I've never been able to get my iPhone to control the volume on the television. Unfortunately I can't find any definitive source on the internet to confirm exactly what's going on.