have u tried adjusting volume levels with alsamixer?
the default values are usually near or at off or very low sound..
open terminal: alsamixer
In the case of multiple sound devices, use F6 to change the sound device you are checking.
once that is checked and verified the volume levels, then open up your pulse audio volume control application (install it pavucontrol and pavumeter) (in terminal type pavucontrol)
once open click the output devices tab make sure the device you want ot use is A
listed and B
not muted --(click the speaker icon to the right of the device name and u will see the word silence-bottom left of speaker headings) being grayed out and then black again. Color black means NOT muted)
then finally open your application, movie, music, whatever you need sound in and if there is no sound leave it running and go back to the pavicontrol window and click the Playback tab. Here you should see your media playing. Click the speaker/microphone icon at the right side and it should display a list of devices detected in your PC (same list as you saw on the output tab) - choose which ever device you want sound to come out of and you should now have sound--if not check the volume levels on your speakers.