ASTRO A50's and ASUS Xonar Essence STX?

Hi guys,

Ive just purchased a pair of ASTRO A50's and am obviously need to get a sound card also. (Currently using onboard of a ASUS rampage formula iv)

I've looked around the internet a bit, seems to me that the ASUS Xonar Essence STX is most likely to be my best choice. (meaning best bang for buck under $200 AUD)

Will the STX allow me to use my 7.1 ASTRO A50's to their maximum capability?

Is there anything Im missing, or maybe any other suggestions?

it's quite a costly investment for something I know little about, any help would be greatly appreciated!!

ASTRO A50
http://www.astrogaming.com/a50-wireless-system

ASUS Xonar Essence STX
http://www.pccasegear.com/index.php?main_page=product_info&cPath=211&products_id =10940