Does anyone have their One15s (or other Ampions) with ears at roughly tweeter level? For the longest time, I had mine higher up so that my ears were more so at the acoustical axis (between the woofer and tweeter) and recently moved them around to where they now sit lower and my ears are at tweeter level. Believe it or not, in my space, this actually works much better. I have a smaller room, which I think naturally accentuates the low end, even though it's fairly well treated. So I think it works better to balance that out with more of the tweeter clarity. I also use a Trinnov and get much better results with it this way. My mixes are translating better too.
I'm sure there are plenty of situations where having the speakers higher up works better, but I just wanted to share my experience and see if anyone else likes them a little lower.