Mesa/Boogie Powerhouse 4x10 Cabinet - $550
For sale here is a used Mesa/Boogie 4x10 bass cabinet. It is incredibly powerful as a cab, but also precise; it can handle your highs and your lows with aplomb. Electronics work perfectly, and the speakers are in top condition. The only blemishes are a few small rips in the tolex on the back. Asking $550, which is really about as low as I can go on this unit.
I see the problem. Your rig doesn't have enough Mesa/Boogie in it.