Soundstage and image height, does it exist?

Whenever imaging or soundstage are mentioned, I like to remind people about these resources: The following provide tests, with which one may determine whether their system actually images, or reproduces a soundstage, as recorded. ie: On the Chesky sampler/test CD; David explains in detail, his position on the stage and distance from the mics, as he strikes a tambourine(Depth Test). The LEDR test tells what to expect, if your system performs well, before each segment. The Chesky CD contains a number of tests, in addition to the LEDR. (https://www.audiocheck.net/audiotests_ledr.php) and (https://www.amazon.com/Chesky-Records-Sampler-Audiophile-Compact/dp/B000003GF3) The shape of your ears’ pinnae is also a variable, regarding your ability to perceive images/locate sounds. A Stereophile article, that explains the LEDR test: http://www.stereophile.com/features/772/  

To quote Bobby Owsinksi from The Mastering Engineer's Handbook:

The LEDR test is a substitute for about $30,000 to $40,000 worth of test equipment.

Stereophile also has an article about it, written in 1989 (!) by Bob Katz:

"My system has great imaging!" "I can hear sound coming from beyond my speakers." "The depth image in my system goes back at least 20 feet." Yes, we audiophiles are proud of our imaging (footnote 1), and we've worked hard to get it. My back is still aching from the last time I tweaked my speakers until the image was just right. Wouldn't it be nice if we had a test to set up and check a stereo system for correct imaging? Yes, Virginia, there is an imaging test—your LEDR is here (footnote 2). LEDR, which stands for "Listening Environment Diagnostic Recording," is available on a test CD from Prosonus, the Studio Reference Disc (footnote 3). The CD is rather expensive (about $50), but there is no other official test for imaging. [Since this article was published, an LEDR track was included on the first Chesky Records Jazz Sampler & Audiophile Test CD (JD37).—Ed.]

Luckily it's 2022 and we don't have to buy expensive CDs anymore, as there is an online version of this test here: http://www.audiocheck.net/audiotests_ledr.php

The Stereophile article has a rather lengthy explanation about what you should hear - the short version again quoted from the Mastering Engineer's Handbook is:

If the sound for the up image doesn’t go straight up from your loudspeaker, six feet in the air as you sit there in your position, then you’ve got a problem with your crossover or with reflections above the loudspeaker.

If the sound doesn’t travel from left to right evenly and smoothly with the left-to-right test, then you’ve got problems with objects between your loudspeakers.

And the same with the beyond signal, which is supposed to go from about one foot to the left of the left speaker, gradually over to one foot to the right of the right speaker, which detects reflections from the side wall.