My friends and I have tested this by trying the same gear in different rooms. Our conclusion is that image height is a function of ceiling height and position of the drivers. Canting the speakers fore and aft can change the image height as well. Give it a try.
Soundstage and image height, does it exist?
On another site, there is a discussion on soundstage, and there are a few people clamming, that, since there is no vertical information encoded on stereo recordings, that soundstage height does not actually exist. It is a product of our minds filling in missing information.
Are they correct?
Please explain your position, with as much technical details as you feel needed.