Q: R5K Sound issues when installing Windows 8.1

Hello everyone

I installed Windows 8.1 Pro as downloaded. I used BCA > USB on my R5K to install Windows.. (Boot Camp drivers via BCA as well). Everything works fine except the sound when using Windows. There is sound, but it all... sounds disturbing, like listening to a radio. Nothing like the sound quality when using OS X, no epic sound effects and crystals clear sound whatsoever. And I think it's not even using all the speakers at the bottom of the iMac when producing the audio. I tried playing with Sound setting in Control Panned, with the audio settings in MPC, VLC, iTunes, re-installed the drivers just to be sure nothing went wrong with the installation and nothing work, I am still getting that "crappy sound quality"...

I am welcome to any suggestions, spend half a day just trying to fix this... Thank you in advance