...

pcm.surround {
        type a52
        slavepcm "hw:1,1"

        channels 6
        bitrate 1000
        rate 48000
        format S16_LE
}
pcm.plug_eq_surround {
        type equal
        channels 6                         # changes channel configuration to 5.1.
        controls ".alsaequal.surround.bin" # sets the control information file to at ~/.alsaequal.surround.bin. this must be changed if there are to be multiple alsaequals of differing channel configurations.
        slave.pcm "plug:surround"
}
pcm.eq_surround {
        type plug
        slave.pcm "plug_eq_surround"
}

ctl.eq_surround {
        type equal
        channels 6
        controls ".alsaequal.surround.bin"
}

...