HDMI ARC and optical do NOT support Atmos, DTS-X or any other high res sound codecs. All you can get out of an HDMI ARC connection is regular old Dolby Digital and DTS. Plus streaming content is always compressed, which makes it even muddier. Sorry, that just a function of the current technology. This soundbar also suffers from having only two speakers in the soundbar, while many other soundbars in this price range have multiple speakers to provide fuller sound.