There are quite a few films with that same name, my personal favorite being this one
The one you suggested is not it, but my love for eastern European cinema has prompted me to add this to my collection!
I have been getting alot of suggestions from members of another message board, and alot of them involve a world that exists after a cataclysm of some sort, which is not the case with the one I am looking for.
The keys to the film I seek are:
*The surface world is completely normal, i.e. present day city (80's L.A.)
*The underground world is actually a sewer system or abandoned subway system, a structure made by surface dwellers but long in disuse.
*The bulk of the underground dwellers are human, non-mutant, homeless types.
*One of the peripheral underground-dwelling characters is a disc jockey, piping music and various comments about the action taking place in the film through loudspeakers which are seemingly all over the sewer system.
*Was made before 1991, maybe 1993 the very latest.
Alot of the suggestions I have gotten so far had one or more of those elements, but none, as far as I could tell, involved the DJ character. Somehow, I feel that he is the key to identifying this film.