The sound is shallow without the sub-woofer since only the tiny left & right speakers are working. There was a fix for 13.04 which made the sub-woofer work but that doesn't work with 13.10. That fix was to append the following line to the end of /etc/modprobe.d/alsa-base.conf
options snd-hda-intel model=ref
If I add that line under 13.10 the sound goes dead and I get no sound from any speaker. Is there some other fix for this latest version?