[daeron80]

Well, if the 57 sounded OK thru the same setup, then about the only two possible culprits I can think of are 1) the MXL is defective, 2) the mbox phantom power is weak, voltage dropping too low. Recording in a closet isn't necessarily the best idea, either, unless it's a pretty good sized walk-in. You might do better in your room. All those clothes can swallow up a lot of the sound and make things sound lifeless.