2.1 + 5.1 Speaker system

[JDiamson]

So, I picked this speaker system up: http/www.amazon.com/gp/product/B00BJE3WEW/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

And I also picked this speaker system up:
http/www.amazon.com/gp/product/B00NI04S9I/ref=oh_aui_detailpage_o03_s01?ie=UTF8&psc=1

Currently I'm buying a 5.1 pcie sound card. But I was wonder how I'll get the 2.1 speaker to add itself to the whole system I have going here? I don't mind having 2 subwoofers. Will I need a 7.1 card instead?

 

[alpha27]

1 or more cable splitters ie 1 input and 2 outputs , done the same thing with a stereo and 2.1, 5.1 sc will be fine I use a sound blaster z and upmix it too 5.1, with 2.1 logitec z2300 150 wat sub.

 

[JDiamson]

So which cord should I be splitting it with my 2.1? The green one? Also will splitters affect sound quality? What splitter is the best in terms of avoiding the quality degredation?