I have just purchased a new Apple TV 4k with a Sonos Arc and LG 65cx TV. All connected with very good HDMI cables. I get no sound when trying to watch shows encoded in Dolby Atmos. I do get sound using my Roku Ultra and the internal Smart apps on the LG. Did all the usual cable, input swaps etc etc. Called Apple who blamed the app makers. How can that be right? They work perfectly on everything other than the Apple TV. There are scores of posts on the internet about this issue. The only fix suggested is to change settings from Dolby Atmos to regular 5.1 surround. But thats not a fix. Its a workaround and a very annoying one considering the investment I've made. Meanwhile I tried to bring this up on the Apple Community Forum but Safari will not allow me to add my comments or start a new thread!!!! Really loving the picture quality form the ATV (hate the remote) but this is so damn annoying.