Coming into this years late, but I've got a Yoga 2 Pro that I can hardly hear. What I did was create a shell script called volup.sh that has this in it:
pactl set-sink-volume 1 +10%
The "1" there is the value that works on my computer. You'll have to determine which channel your main audio is.
Then I set a keyboard shortcut tied to the volume up media key that overrides the normal volume up functionality and runs this script.
The normal increase volume functionality stops at 100%. But this will let you raise it as high as you want. To the point where it totally distorts out.