Try disabling the Windows audio enhancements. I haven't used Windows 8, but the steps are probably similar to the steps needed to disable enhancements in Windows 7:
- Right-click on the speaker icon in the notification area (system tray in earlier versions of Windows) and click on "Playback devices."
- Double-click on your default audio device in the window that appears.
- Click on the Enhancements tab and check the "Disable all enhancements" box. The actual enhancements might not appear to be enabled (their check boxes will be unchecked), but they are all enabled anyway.
I had the same problem, and that fixed it. It also improved sound quality. It also disabled the audio enhancements and equalizer included with the audio driver on my computer. If disabling enhancements prevents audio effects in games from working properly, you will have to enable the enhancements again and live with it. However, I doubt that Creative or Realtek are dumb enough to disable anything besides basic 2-channel audio when the enhancements are disabled like Conexant does.
Also, why do you have drivers for two different audio devices installed? If you have a Sound Blaster card, you won't be using the Realtek onboard audio.