Richard, what makes it even more difficult for me, is that I have the JBL 4312A Monitors, but cooked both the woofers when an amp went DC. Here in Australia, the 2213H are impossible to source, so I had to get the 2213 but when I realised after listening they were opposite polarities, I just went with the battery test to sort them out. I'm pretty sure the mids are in phase, no phasing nulls that I can notice, so I guess everything in phase now, but after all the extra info, I will eventually run a Phase Checker when I find it.... Thanks heaps for all your input.