DescentBB

Is there any way to add a sound to a level that only plays once upon joining? Maybe in a briefing? Maybe in the level itself?

Yes, in the DALLAS editor, make a new script, make the owner the level, set the trigger to Level Begin. Then down in the section of things that should be done when the conditional is met add \"Play sound for all players\". That should do it, it's been a while since I opened the DALLAS editor so it's possible that my instructions are less than perfect.