It appears that music plays when you log into the game no matter what. I guess it's default module music but I can't find a way to turn it off. There is no trigger, it just starts playing as soon as I do. It seems to override any music I put down. Really annoying.
I assume the one you are talking about is the D:OS main menu theme? You can hear it if you load up main.
If that's the case, yes this is a rather unfortunate bug with the enhanced edition (classic didn't do it). There is a fix though.
If you want NO music, there is a playlist called something "Transition". It's just silence. I don't remember what it is called off the top of my head and I can't get to my editor at the moment.
So to do what you describe, have the surrounding rainforest have the ambient sounds, you have those working so just find that transition playlist and add it as the music for that area.
Then have another trigger inside the bigger rainforest trigger just for the cathedral. Put the right playlist on that one.
Poly shape triggers are excellent for buildings since you can make them just the right size.
