Why does the music change to very tinny every time I type?

I have been having this problem for a little while now, and I want to listen to my music while I type (on Skype or even on browser), and it is really annoying me. Dolby Mobile is enabled and I don't know if this is the problem or not. Without it, the audio is very... horrible... I mainly listen to music through my headphones (cause my family doesn't exactly approve of the style of music that I listen to, so I don't play it out loud), but I tried this afternoon, and even without the headphones, it still does the same thing.

Please help with this!!!!