IME, one cannot ABX speakers like this, using different positions. The different position gives more than enough cues to easily identify each speaker. Even with two same speakers. One is easily recognized as the upper speaker and the other is the lower, simple as that. Please try that first (stack the Genelecs on top of each other) and only if you completely fail to ABX them you might have a chance to test for actual differences of the speakers proper.
There is a reason why all professional blind speaker tests use a (semi-)automatic shuffler to load the exact same playback position for every speaker.
I tried, but I cannot tell the difference in height. This is at a 20 foot listening distance, and the tweeter height difference here is maybe a foot or two when stacking.
Have you tried distinguishing height differences like this? I find it vastly more difficult than horizontal differences, which are quite obvious.
Building a robot capable of shuffling a speaker as heavy as the Salon2’s is just not practical for me, so an alternate needs to be chosen. This vertical stack seems the best candidate so far.
Anyway, I will never be able to match the positions perfectly even if I could use a robot, because this is comparing a 3-way coaxial standmount with a 4-way non-coaxial floorstander. I suspect Revel’s robot does not normalize height differences between towers (though I don’t know this), because if you did you would have to choose a reference axis, and this wouldn’t really even make sense for towers.
For example, how would Revel make the Salon2’s tweeter as low as the F208? You just can’t do this unless you either raise the F208 way up (not how it was designed to be used), or dig a hole and sink the Salon2 into it (not how it was designed to be used). They were designed to be floor standing. So I would be surprised and skeptical of any test procedure that tries to mess with that.