Utility, by 
IN A NUTSHELL: This program is mostly obsolete!
Back when bass.dll support didn’t exist, this program was great. You got smaller tracks which sounded the same on Jazz2’s module player. And also being a time where dial-up was far more common, anything to decrease the filesize was great.
Also, it was used to convert modules into boss tracks when there was no scripting support to change music at bosses.But those times are over. Unless you want to make a single player level which is entirely compatible with vanilla JJ2 featuring custom boss music – you may want to use this. Otherwise, I don’t recommend levelmakers to convert to j2b at all.
It does not support some module effects and JJ2’s in-game module player can give out crackle sounds. Worse case scenario – a sample keeps playing in the background and never ends. I also recall it may have a filesize limit – I’ve had my game crash by trying to load a converted j2b before.There is an alternative, though it is plus only. mo3 is a far superior compression format. Not only does it make files even smaller than J2b, but mo3 has much wider effect support. Bass.dll is also a much better player than JJ2’s default. Here’s a guide on how to convert modules to mo3;
http://www.jazz2online.com/jcf/showpost.php?p=479930&postcount=5
EDIT: Fixed up some grammar and spelling issues. Made it a little more brief. Also added another con of using j2b.