I do know why. It's because I'm running all my programs on user mode : I have
no Display Manager, and I run my WM with 'startxÍ'. The problem is, if I'm
on super mode (loged with root), the sound works well, but not on user mode.
My sound is at 100%, alsamixer shows me.
So, how can I fix it?, with 'startx' still used.