Aside from that, if you're looking to create/edit your own sound files, there are some things u need to be aware of.
First, the sample rate must be set to 44100mhz. Most basic sound editing programs can convert sound files sample rates as needed
Secondly, sound files that have 2 channels (ie Stereo) won't be accpeted either, so they have to be converted to the Mono set.
And then the only formats EF will accept is WAV or MP3.
Aside from that, Scooter's advice is the way to go.
Open up pak0.pk3 and have a look at the animation.cfg files of any of the Borg or Klingon models to see the soundpath parameter in action.
Hope that helped!