If can avoid using mp3 at all, it should be done- period. The only time you should be using mp3 is for web purposes and, as I think you are OP, you use the highest kbs you can- certainly never less than 160kbs. Some sites will limit you to file size and you're forced to go with 128kbs- not good. And of course, it's convenient to dump mp3 to portable devices such as phones and ipods but even then, unless you're severely limited in storage capabilities, you should always go with your full res files. But anything written to CD should be 44.1/16 bit res- cd audio quality. But really folks, it's doubtful this is an mp3 issue or or wav file issue or anything like that at all. It's a mix issue.

When you say all sounds great using WMP, what speakers are you monitoring that playback from?

What audio monitors are you mixing with in the first place?

'Mackie mixer/BBE/JBL eons' -That's not a maximizer I see in there is it- that BBE? That'll change things too and imo, usually not for the better.

PA speakers are full range speakers. It's another speaker to judge the mix you've done. If it sounds crappy through them, your mix typically needs adjusting. In my opinion, you're just getting another listen on different speakers and they're telling you something- your mix needs adjusting. Or, your channel eq's need adjusting.

You could also check to see if your cd players bass boost is on to some extent, and that there is no eq preset going in the player. It wouldn't hurt to try a different player too. Good luck.

Btw- the issue of volume discrepencies between tracks is a mastering issue. Mixes should be uniform no doubt, but mastering is one of the processes that evens volumes between tracks. There is software out there these days to handle that. I like Sony CD Architect for the task. Just normalizing the tracks will not make all of them uniformly even in gain.

Dan