I have been using a test CD to check phase, this also has pink noise bursts alternating between left and right channels. I had previously noticed a different quality between left and right with the pink noise, and so was extra careful when I went over my speakers a few months back to make sure they were wired exactly the same all the way through (as well as a proper clean out of HF magnet gap and very careful HF realignment with a tone generator) Since then I had still been bothered by a channel imbalance and so this afternoon I quickly went in and flipped the wires around on the HF unit of the perceived weaker speaker. I have to say this seems to have done the trick!
Cooky I just grabbed a pair of your HPD Labels today as well for my Eatons