Since you (apparently) reversed the wires at one of the speakers at random, you might now have both +'s hooked to the minus sides, and vice versa.
Now try switching the connections at both speakers, your imaging should remain the same but you should hear more (or less) bass. If you have more bass, leave them as is; if not, switch them back.
Now try switching the connections at both speakers, your imaging should remain the same but you should hear more (or less) bass. If you have more bass, leave them as is; if not, switch them back.