Comment 7 for bug 207312

I dunno about the pulse and pulse-access groups, I would think that they are important.

Thanks for the tip with /etc/default/pulseaudio. I did not enable system mode there as the comment in the file recommends against it. However, the comment also mentioned that esd should be enabled in the Sound preferences, and for some reason it wasn't. Checking the "Enable software mixing (esd)" box on the Sounds tab fixed my problem.