Tweeter height...align with ears?

I like Erikt's response. In your small room perhaps you should be more concerned about the rake angle of the speakers. It looks like there is potential for some reflection off the ceiling.

There is an old rule of thumb that is said to apply only to conventional dome or cone tweeter/midrange pairings and that is to put the tweeters just a little above ear height. However, the reason for that advice has little or nothing to do with the highs. It's really to smooth out a response wrinkle in the upper mids. But, even among the conventional speaker designs this might apply to, there can be exceptions. The reasoning that Erikt and Lowrider are referring to can sometimes be taken advantage of to place the soundstage as high (or low) off the floor as you require.

I have an old pair of German Magnat speakers that are 3-way cones using titanium domes. The 'slightly above' rule works good for them, but I had to go through some experimenting to eventually confirm it for myself. The odd part about these particular speakers is that both tweeters are actually offset to the left of the vertical center-line of the 2 woofers and midrange, making the pair NOT a mirror-image one. I was never really quite sure exactly why that was done, unless it had to do with trying to reduce the cabinet diffraction peak that happens when the distance from either side and the top of the cabinet edge from the tweeter are all the same distance (which works to combine the individual diffraction peaks at the same frequency - spread out the individual edge distances and you spread out the overall diffraction peak). You'd think, since both tweeters are offset to the left, you'd be able to hear this somehow in the soundstage, but I haven't been able to yet, under any circumstance, in the 24 years I've owned them. Not sure why that is.

Every monitor I've owned the manufacturer suggests ear height! I always use 24 inch stands,you can always make them higher but you can't make them lower!

Thanks guys. Unfortunately the stands that came with my speakers are not adjustable for height or rake. I was messing around with toe in last night which seemed to help get the coherence right. I will test out different height chairs today to see if getting my ears up to tweeter height helps.

And Lowrider I was actually planning to add some absorption on my ceiling in the near future.

Assuming the speakers are the Sonus Fabers listed in your system profile, you do not have to sit at the tweeter axis. Sitting slightly lower than the tweeter will not substantially change the treble balance. Stereophile reviewed the loudspeaker and performed measurements regarding dispersion characteristics. The review did note that loudspeakers where particularly sensitive to setup.