I would try to get the NF4 audio working first. The binary, 64-bit only X-Fi driver may be a huge pain to get working if it has kernel version dependencies, etc.
Try running a mixer first (something like Kmix) and see if you have any detected sound devices that you have mixer controls for. If it hasn't been configured by the installer, most of the time all of the outputs start out muted and turned down to 0%. You can also run the command "alsamixer" and see what the output is. If you get an error that alsamixer is not found, check to see if the alsa-utils package is installed.
After checking the first items, you might want to try running alsaconf (also in the alsa-utils package). Note that you'll have to run alsaconf as root. If none of those work, we'll have to dig deeper.