Comment 1 for bug 683901

I can confirm that the internal microphone doesn't work.
I have Acer Aspire 8943G as well.

I have also tried the package linux-alsa-driver-modules-2.6.38-8-generic version 2.6.38-8.201105230750 from Ubuntu Audio Dev PPA and a bunch of "model" options for snd-hda-intel in /etc/modprobe.d/alsa-base.conf (among others to get the 5.1 surround built-in speakers to work - Ubuntu only recognizes them as 4.0 and the center speaker and subwoofer are not functional at all then) but with absolutely no result.

As dreKion wrote, the chip is ALC670.
I am using Ubuntu natty.

If you need any additional info, please let me know.
Thanks.