I have seen good reports of Outrec (http://outrec.sourceforge.net/) for recording computer playback. But while some people say it works well with Ubuntu 12.04, I cannot install it on 12.04.
I tried installing outrec_0.0.3-1_all.deb in Software Center. It says the packages are not trusted despite I did sudo add-apt-repository ppa:techm3/outrec which seems to make it a trusted software source. I know updating the PPA does not work as others have said.
Can someone check if this package is actually installable (or compilable) on 12.04? Thanks.
You may also try audio-recorder.
Please see http://ubuntuforums.org/showthread.php?t=2073739
It works on my 12.04. Just download the deb from their site and install it. Never mind the "untrusted software" warning, it just means it is not official. The ppa doesn't work.