A:AnswerI called BestBuy support regarding this and was informed that this model (hw-q90ZA) is made solely by Samsung while the HW-Q90R/ZA has been "tuned" by Harman Kardon and has some "slightly different [read: upgraded] components".
A:AnswerStuart, I had the same issue with the Q-90. With the rear speaker volume set at +6 (Max) very little sound even when watching Dolby Atmos source. Also soundbar right up-firing speaker became distorted. Returned soundbar to BestBuy
A:AnswerYes it will work. This is the same setup I use with my UHD player so that better sound can be played even if the TV might not output Dolby Atmos.
A:AnswerHad a similar issue as well so what u need to do is update the firmware on the soundbar and update the firmware on the rear speakers/sub and the issue is solved and the new updates gives u eArc as well and it’s displayed on the soundbar too. Visit the Samsung site to learn how to do it if u don’t. I simply downloaded SmartThings app on my iPhone and updated the soundbar without any issues and after the update I pressed/held the down button on the circle on the remote for like 5 seconds and u can see the update happening for the rear/sub speakers on the soundbar it will say update and start counting then it will power off and restart and you are good to go! I hope this helps you!