Thanks for everyone who suggested this work around to use two cables (one for video, one for sound) but i've noticed a difference in sound quality and volume between ARC to AVR and direct to AVR.
ARC sounds a bit better and louder compared to the second screen which goes direct to the AVR.
Volumes and settings seem to be the same so i'm a bit confused, both audio drivers (Nvidia) are in stereo and are set to DVD quality at 100% volume.
The settings seem to be the same for each input on the AVR too plus i've tried two different DP-HDMI cables
My set up that gives back glorious surround sound
:
VIDEO: Graphics card - HDMI-HDMI - LGCX TV
AUDIO: Graphics card - active DP-HDMI - AVR-X2300W
One other thing that i've noticed is that when i make a custom resolution in the Nvidia control panel (to get 30fps instead of 60) i get no sound at all, i'm not sure why this is happening.
For audio i have my second screen set to 480p 60Hz (720x480), is it possible to go lower than this?
Thanks for any help.