Comment 6 for bug 478867

Set Input Source 0 as Int Mic as you told me. Sorry, I was a Windows user so I don't know all that well terminal commands. Think that there should be a GUI for this, but this is not the problem. Still the internal mic does not to work. I've done a few tests.

I turned up the volume levels to the maximum (in AlsaMixer and checking the result also in termina): Line In, Mic, Mic Boost, Capture 0, Capture 1. I hear the static (that's the mic boost), but no signal at all in Sound Preferences /Input tab or PulseAudio Volume Control or PulseAudio Volume Meter.
Input Source 0 is Int Mic, Input Source 1 is Ext Mic.
I tuned Mic Boost to 30% just to cut the static.
Connected my Logitech external webcam, it appears in Sound Preferences/Input tab. Choose it and everything works smooth. Then I choose again Internal Audio Analog Stereo and some signal appear. But in PulseAudio Volume Contro and PulseAudio Volume Meter still no signal at all, so I think it's just and error in the Sound Preferences.
If I disconnect the webcam, again no signal at all.

Sorry, that's the only think that's not working and I'm quite sure is a common problem to Acer Aspire users (already checked the forums and followed a lot of 'solutions').
Thank for your help, meanwhile.