I have a C-Media audio device, which linux seems to have less than desirable support for. Is there any way in amarok to duplicate the 2 stereo channels of mp3\'s etc. to 4 channels or rear speakers? i notice all audio players on a windows machine do this, but none do it on linux, it would be a nice feature (^_^)
does anyone know how to do this?
-jake

I didn't have to do anything to make it use all my speakers (Creative Audigy XZ, 7.1 setup and Opensuse 10.1 rc1).

Maybe you can try to create an appropriate .asoundrc file, to upmix your channels (search google for "asoundrc upmix channels" or something alike), there are examples out there.

Also, make sure all your other speakers are actually activated (volume not zero), as this may be the case by default.  Try "alsamixer" as root and check your side speaker slidebars (and any other).

Little help, I know, but it is possible 

If you use the xine engine, try setting the speaker config to "pass through".