I am assuming you already went into the menus and made sure it was not muted in game 
The first time you start up, I recall there being selections for both sound and video modes ... perhaps you need to use a different sound mode? Not sure how to get back to those "first time" choices ... I think you can run the 3dconfig (or some file named something like that) manually.
Might give that a try ...
Tools for Wizardry(r) 7