My Logik L22LID18 screen has no sound on HDMI ?

Hi my Logik Tv has had this problem as long as I can remember, when I'm playing my games consoles on this TV there is a problem I get where it doesn't pick up characters voices but plays the background music and noises, however whenever I turn my head away from a character there voice returns. In a shorter version when I look directly at NPc's there voice isn't picked up, any help is appreciated.

The screen also dims completely when I go on the pc output, I've tried adjusting the setting on both the TV and the computer but have had no luck, the sharpness, colour and tiny option are also locked.