I was using a conventional PC 5.1 speakers that used three 3.5 mm jacks to get 5.1 audio from the PC. I have never had any problems although they were the super cheap Logitech Z506.
Now I switched to expensive sound bar with surround speakers and stuff and the problems began.
After hours and hours I managed to make it work in the following setup:
My PC is hooked via HDMI to the TV blasting video and audio there.
My TV is connected to the speakers VIA optical cable.