I don't know if this will be much help but I imagine you need to go into the vierra settings under sound or external settings. I have not tried myself but a TV as sophisticated as this vierra I would be surprised for there not to be a way.
By Faisal Alfaqih on April 17, 2016
VideoSecu Tilt TV Wall Mount Bracket for Most 23"- 65" LCD LED Plasma TV Flat Panel Screen with VESA 200x100 to 600x400mm, Free HDMI Cable and Magnetic Bubble Level BBM by VideoSecu
By J.F on December 26, 2012