If you decide that a permanent change is called for (which several posts have suggested is open to doubt), Metaphysics is certainly right that switching speaker cables is the way to go. Changing XLR pin connections is doable but more work and you might someday forget that you've got an oddball cable, a point made by Robert Harley in his "Complete Guide to High-End Audio". I have it on (what I regard as) good authority that it's a rare CD that maintains the same polarity throughout, so a phase reversal switch, if you have one, will have to be used a lot, if you notice a difference.
