I had a problem with the built-in mic in my netbook (Acer AO751h, with Ubuntu 12.04) and fortunately I solved unstalling pulseaudio and then installing ALSA driver. Now everything is alright! Actually even Skype (version 220.127.116.11)! The only problem is that the volume keys (in the keyboard) do not work. Is there any way to fix it? Thanx!