Comment 3 for bug 988098

Now I don't think this works within ubuntu because of the sound system used, but if anyone is willing to test this...I had the issue myself where the audio was so unbelievably low that it sounded like the headphones had no audio even at full volume (you had to listen extremely carefully). But try booting xubuntu. Open up the sound preferences (pauvcontrol) when the headphones are plugged in. Change the "port" from headphones to speaker with the headphones plugged in. I wind up personally getting full sound through the headphones, and not the speakers. It seems the speaker port works for both headphones and the normal speakers, while the headphone port causes extremely low vollume.

My system uses a similar sound chip to the bug reporters. An ALC model that uses the Intel HDA sound drivers.