I am using ubuntu 12.04 and I chagne to xfce 4.6.
Then I found that I can get no voice when I play a mp3 using the audacious or watch some video in youtube.
And I found the xfce-mixer which is used to control the voice in xfce.
After some setting I can listen the song but with a very noise background-voice.
Normally, a song will conatain the singer's voice and the background music. Now the background-music is higher than the singer's voice.
This is my setting of mixer:
As you can see, there are two scroll bars.
After some test,I found that the left control the singer's voice, and the right control the background-music.
However when I scroll over the `mixer track in the lower-right of my desktop using the mouse scroller, the singer's voice will get synchronized with the background-music:
Do I miss anything?