Soundstage and image height, does it exist?

My understanding of human sound perception of height is that it occurs mostly in the pinnae, causing the tonal relations and phase relations to change at the eardrum. There are no timing or level differences that can give us height information so a two channel playback system doesn’t inherently have anything to work with. But we may perceive a ceiling echo in a concert hall recording as coming from above from other unconscious means of deduction. You could say it’s our imagination but it would be informed imagination. If a recording is made using a dummy head then tonal relations associated with height do get encoded onto a 2 channel stereo recording. All directions are possible, but it usually doesn’t work super well because 1. Our pinnae are not all the same, and 2. The sound goes through the pinnae transformation twice - once at the dummy head microphone and again when the sound from the speakers hits your pinnae. My experience with listening to dummy head recordings through speakers is that the height effect can make it through all these issues with powerful effect sometimes. I have a recording of airplanes flying over that creates a very powerful directly overhead effect on every speaker I’ve tried so far.

Any system that has a tonal response that mimics your tonal response for height can cause a height effect for you. Ceiling reflections can also create a height effect. And of course speakers up high can create that effect. My speakers tweeters are higher than my seated position so I have an elevated sound stage.

If height information is encoded in a recording I’ve found it doesn’t take much of a system at all for it to be perceived. Pretty much any basic system will make it work. Height perception should even work in mono. I’ve found it also easy to get sounds extending well beyond the speakers to even behind the listener. Speaker placement and listening position are a little more important for the wrap around effect but it doesn’t require a great system. I find forward depth is far more difficult for me to perceive, pretty much impossible if I can see the front wall too close to me, although it can work if I close my eyes and the system is well balanced tonally and speakers positioned well.