My tv is a Samsung smart TV model no. UE48JU6400 , and I have only just started using the smart hub.
When I want to watch a program, say on BBC iPlayer, or any other app, the sound from the TV channel which is currently on, still plays with the sound from the app, BBC iPlayer or anything else.
I phoned samsung support, and after resetting the TV, there was no change, except the NOW tv app would not run, saying NOW tv is currently unavailable. I was given a numbere for a service centre nearby, but thought I'd try here first.