10x12x7.5 room. M2, M3, M5, M2OW, M5OW...all v4...don't work on short or long wall. The M3 and M5 are too boomy and the M5 is easily discoverable. The M2 disappears nicely, no boom but bass is not lush.
The M50v4 is a slam dunk. No matter where I place them, they sound fantastic! No EQ required. They are absolutely transparent and 3D image like crazy. I hear the Pink Floyd chopper swirling from the front to the side, behind me and back around the other side to the front. There is no song, no matter how old and badly recorded, that doesn't sound holographic. As these M50s illuminate all the walls, the sound stage width and depth is absolutely immense. I'm set up in an almost equilateral triangle with the speakers on the long wall almost 10 feet apart.
The relatively low height of the tweeter does wonders in low ceiling rooms because ceiling reflections are attenuated and the tweeter normal is below ear height lending to the disappearance effect. The cabinets are acoustically inert which also doesn't give them away. And the lack of a dedicated mid-range also naturally minimizes resonances.
I've brought twin EP125v4 in here and my Yammie sub. I've set the 125s as left and right feeding from my OhSoSweet Pioneer pre-amp outs. The Yammie is being fed both channels and is in the back. I actually enjoy the M50s without any subs! I can definitely tell, from my experience with my active subs, what's missing but I don't care because it sounds so good as is.
I've asked Andrew for the SP and LW plots. I think the LW plot on the product page is old from maybe v2 or v3. These M50s may be the most linear Axiom passive floor-stander across their stated operating range.
When I listen to my ALFR and active sub system, the difference in clarity is startling. But in this small room, the M50s 3D image and disappear much better than the other room/system which is more than 4x larger. This room also gives a much more intimate presentation like one is in the first few rows. The other room is like way from the back.
Surprisingly, the reduced clarity is not a bug but a feature. Likely because the all-important mid-range has been kept largely resonance-free in the important bands. The mids remind me of my Bose 601 series II but that's where the similarity ends.
I love them. I'd like them in real ebony vs. vinyl but I'm not going to dare letting go of these! | 
