Just thought I would share this because I googled around for a long time before finally finding an answer.
This is for people who want to be able to output audio to multiple soundcards.
I use this because I have no center speaker hooked-up to my surround because I prefer to use the TV Speakers as center channel instead. So I have 5.1 signal going to the surround through coax and stereo to my TV through HDMI audio.
Install Pulseaudio preferences
Run paprefs and there is a checkbox to enable simultaneous output to all local sound cards.
sudo apt-get install paprefs
Once you do that simply select simultaneous output as default output in sound preferences. (I prefer pavucontrol on 11.10) From there you can set-up, in sound preferences, your speaker types to each device.