I love my Tab S but the volume level of the built-in movie player is a little low (probably due to elderly ears :-))
Is it possible that an add-on movie app (free or otherwise) might provide a little more noise?
PS: Dunno if it's relevant but the movie sound is coming to me via Harmon\Kardon bluetooth headphones.
However, on reflection, I don't think it's anything to do with bluetooth, because if I just listen to music or e-books through the cans, the volume is more than adequate.
So I think it must be the default movie player that's responsible for the reduced volume.