You have a good onboard audio on that motherboard, you don't need to spend more on a sound card, the extreme 4 contains the ALC898 which is Realteks lastest chipset, and achieves the highest SNR ratio out of ANY onboard solutions. (110DB SNR)
See the specs :
7.1 CH HD Audio with Content Protection (Realtek ALC898 Audio Codec)
- Premium Blu-ray audio support
- Supports THX TruStudio™
http://www.asrock.com/mb/Intel/Z77%20Extreme4/?cat=Specifications
No need for sound card.