Audio
SupremeFX III built-in 8-Channel High Definition Audio CODEC
- Supports : Jack-detection, Multi-streaming, Front Panel Jack-retasking
Audio Feature :
- SupremeFX Shielding™ Technology
- 1500 uF Audio Power Capacitor
- Gold-plated jacks
- Blu-ray audio layer Content Protection
- DTS Ultra PC II
- DTS Connect
- Optical S/PDIF out port(s) at back panel
I assume you have installed the drivers as per your OS and if the system is still not working then something is wrong.
However that being said, if you look at the playback devices right click are speakers detected, not via the HDMI cable of course. It might just be you need to set the realtek driven speakers as active.
To help us help you - please provide as much information about your system and the problem as possible.