Asus XONAR STX and Edifier S550 Encore

[Iamcid]

hello, i own an Asus XONAR STX and i was wondering if its a smart choice to pick Edifier S550 Encore as 5.1 audio sistem. Im kinda new to this and i dont know whats best to pick. STX is a stereo card and i can plug a 5.1 system through a digital port so far i know.. question is.. will it kill the quality or something if i connect this Edifier S550 encore through that port or i should pick Edifiert S730 that is a 2.1 sistem ?

 

[Iamcid]

I still dont know what should i buy for my asus xonar stx as a sound system