Thanks for the input. I really love this receiver but some of its oddities make me want to take it back. For example, showing on the front display both Dolby atmos/Dolby hd is one of them. I wonder if my 4K cable going from Sammy 4K player to receivercould be the culprit. Will try w a new 4K hdmi cable tomorrow. If you have a pioneer receiver listed on this thread, what does it display on the front when you play a Dolby atmos 4K bluray movie?? I know you have to toggle the info button on the avr remote to show what audio codec is passing as well as resolution of 4K bluray. Will Check Sammy audio settings too. Yes, I understand that Dolby atmos is subtle like rain, wind and ambience noise unlike full surround.I'm sure you'll get it to work. If the test tones have sound, then it's working. I have the Sony X800 HDR blu-ray player, and to get Atmos or bitstream, you have to go into to sound settings and set BD audio mix to off. Possibly your Samsung player has something similar.
Keep in mind, Atmos is good, but more subtle than when you first heard surround.
Thx for your time,