7.1 audio receiver

[Enderman]

Hey guys I just had a question about the audio I am currently using.

I have a 5.1 HT Receiver for my 14.2 surround speaker setup, but I only have stereo input ( L and R ).

The 7.1 audio from my PC is not being used  because my receiver only has left and right inputs.

I did a bit or research and found a few uber high end Onkyo receivers that have full 7.2 audio inputs.

 

If I wanted to get 7.1 adio connection from my PC to my receiver would I need to use SPDIF optical?

Also, will this deliver better positional audio in games?

If my ideas are correct, in a game that sound is coming from behind, the rear speaker outputs would be louder. But since my receiver only has left and right then I will hear front and back speakers as if they are all front.

 

My receiver is a Sony STR-DH510

 

Thanks in advance!