Watched entire season of HDM on FTV4K on HBO Max and did not have any of the poor sound quality issues you describe. I just ran S02E07 of HDM through HBO Max on FTV4K and HBO Max on TCL Roku TV and didn't notice poor sound quality. I am just sending DD+ to a simple Vizio 5.1.2 soundbar.What device are you watching the show on? Because on Fire Stick 4k and XSX the sound on HBO Max is very compressed sounding. His Dark Materials is an especially bad offender.