Audio unclear.

Hello,

I have a problem with my audio
I'm using Dolby Digital Plus and Realtek, well that's what I checked in my system.

Here's my problem..
Basically, I'm a headphone user and listen to music as usual, but one day as I listening to my song I realised that the audio quality itself changed drastically. Because it is an audio I couldn't show it..
But the changes is that the audio makes every song so different in volume.
Such as background music is high in volume but the vocal is low in volume, making it unclear for me.
It also gave me a hearing that the music is played at a distance instead of next to me.
Another thing is that the volume I set as usual is surprisingly low since then.

I have tried to change headphone but the result remains same.
I wonder if I should uninstall Dolby or something else...?

Try finding the latest driver for Dolby and install it, you need to fill up the system specs to get more help.
http://www.eightforums.com/tutorials/49651-system-spec-fill-your-eightforums-system-spec.html