Your problem is not having the drivers installed for Audio .
Did you try to use Multicast 7.41 .Drivers>Audio>Realtek?
If you have already tried that and not able to fix the problem:
To know what drivers you need, you got to first find out the Exact Chip for Audio on the Motherboard.
Since the motherboards are primarily released to support Windows and Not Mac or Linux, you won't get a lot of very clear information about the Audio Chips from the manufacture's documentation, but from the name of the Driver shown on System Specifications or Driver downloads, , you may get some idea for example: Realtek Audio.
From windows Device Mangher >Audio>Properties you may be able to get the device ID and using that you might get going to find the Codec .