Mine

#This asoundrc is a template to create a file that will upmix 2.0 (stereo) files to 5.1 speakers.
#It will also playback real 5.1 sounds, on 5.1 speakers, and also allow the playback of both stereo and surround sources at the same time.
#It may not work out of the box for all cards. If this is the case with your setup, please speak to me (wishie) in #alsa on irc.freenode.net


# 6 channel dmix:
pcm.dmix6 {
     type dmix
        ipc_key 1024
        ipc_key_add_uid false
        ipc_perm 0660
        slave {
                pcm "hw:0,0"
                rate 48000
                format "S32_LE"
                channels 6
                period_time 0
                period_size 1024
                buffer_time 0
                buffer_size 5120
        }
     }

# upmixing: 
pcm.!default {
        type route
        slave.pcm dmix6
        slave.channels 6
        slave.format "S32_LE"
        ttable.0.0 1
        ttable.1.1 1
        ttable.0.2 1
        ttable.1.3 1
        ttable.0.4 0.5
        ttable.1.4 0.5
        ttable.0.5 0.5
        ttable.1.5 0.5
   }