I found what's happening. I opened alsamixer and pressing right arrow about 10 times, at the end of the menu there was an option: Speaker which i turned on and strated the sound. When i use OpiePlayer for listening a mp3, despite it works, the volume controls (both OpiePlayer and opie volume applet) are lame. The only one that works is alsamixer. Is there any way to configure this in such a way that volume controls work? for instance configuring opie to use alsa, so when i change volume optiones in opie volume applet, they work.
Thank you in advance
PD: i guess the sound stopped working in first instance when i opened alsamixer the first time