Audio problems when gaming

[onstrings]

Dell Vostro 260 Mini tower
i5 2400 3.1ghz
XFX Radeon HD 6870

I recently bought this desktop and upgraded the PSU and GPU. For a few games that I play, however, the audio doesn't completely play.
A common issue is background music just disappearing. All other sound effects play, but the background music itself is nonexistent.
Examples: Sonic Generations, Dolphin emulator

I can't figure out what to do or change, and I've been googling this and haven't found anyone else who ONLY had absent background music as part of their problems with audio. (Also didn't know which category/subcategory to put this under so here we are, under sound cards.)

 

[gamerk316]

Question: This happening only in Dolphin? Its default audio engine (HLE) sucks. LLE is better, but you take a significant FPS hit, and you need to aquire the necessary file (legally, of course) for it to work.

 

[onstrings]

Question: This happening only in Dolphin? Its default audio engine (HLE) sucks. LLE is better, but you take a significant FPS hit, and you need to aquire the necessary file (legally, of course) for it to work.

Ok, I'll look into that, but that's only for Dolphin.
The game I'm getting mad at currently is Sonic Generations. Everything but the background music plays.