I too recall this...it seems the main goal with tweaking the HE-400i at this point is to improve on efficiency, but the goal of having a similar signature to the HE-500 remains relatively the same which is good news. As long as it has a fairly rich/fullness to it, and sweet mids...I'd be game. I can imagine the tuning process to be quite difficult when you're trying to increase efficiency and retain the same signature, especially with the single sided magnet. I'm curious how the diaphragms/housing will look, and if the tracings will be in a different configuration as a result (or as a way to increase said efficiency). I'm on the edge of my seat!