Mac Pro - Connect 4.1 speaker system?

[piperpilot12w]

I have a Mac Pro and a set of Klipsch 4.1 Pro Media speakers/subwoofer with 1/8 Jacks for front and rear.
I'm coming from a Windows PC that had a sound card with both front and rear outputs.
Looking at the Mac Pro, it appears there is only 1 analog out jack?
How do I get all 4 speakers working with surround sound?

 

[aaronw1986]

Do the speakers have an optical (SPID) connection? Cause the mac pro does, that's how my logitech 5.1 connect.

 

[piperpilot12w]

Just has the 1/8 mini plugs. No Optical

 

[Locoweed]

Firewave

Amazon has them.