When I watch Netflix on my TV and try to have sound through my receiver I get background music etc fine but dialogue is quiet and sounds like it's coming through a harmonica microphone. Surround logo lights up on the amp and everything but just weirdness comes out. Because of the way my house is setup I can't connect the TV to the amp through anything other than HDMI so ARC is the only option if I want surround sound out of it.

Any tips or tricks to sort it out would be appreciated. Have messed around with settings in the receiver and TV with no luck. 

LG UH770T - Software Version 5.30.35

Netflix app - v1.4.58

Onkyo TX-RZ710 - Latest firmware

5.1 through Polk 265-RT FL/FR, 255c-RT centre, 90-RT RL/RR, and a PSW10 sub (not that the speakers matter at all)