I don't know if by now you've figured it out, but I just purchased the Apple TV 4th generation recently. I already have a Bose Sound Bar connected to my cable box and TV. All I did was plugged my Apple TV4 HDMI cable into the Sound bar's "Aux" HDMI and it worked just fine. When I want to watch Apple TV, I just select the "Aux" button on my Sound Bar's remote and Apple TV comes up on my TV. I figured this out because looking at the back on by Sound Bar's receiver, I saw that everything I needed sound to be heard through the sound bar was connected into it. For example TV, Cable, DVD and now my Apple TV were all connected to my sound bar receiver. Hope that works for everyone who at least has a Bose Sound Bar or a sound system with a "Aux" HDMI connection open.