ZB ships with very old included shared library files. The 2 that cause your linux sound to be unreliable or nonexistant are openal and libasound.
You can replace openal and libasound yourself, or download our gaming groups' repack here:
http://ugn.shackhost.net/zeroballistics ... und.tar.gz
If you do it yourself, remember to name the updated '.so' files to match the name of the ones you are replacing. (eg: libasound.so.0 being replaced by libasound.so.1 should be renamed to libasound.so.0)