Really? Cause when I hear things that are out of phase like this (the correct term is reversed polarity, I guess) it sounds much weirder than just phasing due to delayed signal (which is a comb filtering effect, where parts of the signal will be more or less out of phase). It sounds like the sound has been turned inside out or something. Really messing with your head Of course, I sit right in the middle between two monitors, where the effect will be most noticable.
I just don't get the delayed signal part from swapping the + and - cables, since you aren't delaying any signal, you're just making one speaker push out when the other sucks in. Doesn't really matter though, as long as the original poster gets relief. It's incredibly frustrating to have awesome gear and it doesn't sound right.
Pete