Image depth

"Then one "BIG" step further is to remove the back wall from in between the speakers like I did, leaving a little 1-2mt behind each speaker for bass loading" Awesome George!

It gave me double the depth and imaging that I had before with the wall in place.
Here is a rough drawing of it. https://ibb.co/9g5VW5W (when it opens click it again to enlarge it) , many in Australia have copied it after they’ve heard/seen what kind of image and depth it presents.

The speakers are ML Monolith III’s with the much better Neolith ESL panels, 12" bass drivers are much better than the stock one

And later if you need to sell the house, you just put in 2 x double fold away doors that fold back against each of the 2 short walls.

If you have a look my editor/reviewer friend of Soundstage he did similar with his after hearing mine with his Alexia’s, installing a big bay window between the speakers to give more distance, (the equipment rack is just in between for picture purposes and lives on the side out of site).
https://forum.audiogon.com/discussions/wilson-alexia-2-3

Cheers George

Can anyone offer a technical explanation of how a stereo system recreates image depth?

As far as the recordings go, leave that for others, but how to get your system to extract the most do this.

 Remove anything between the speakers (equipment racks ect) and you’ll increase the depth perspective as your ears and eyes hear and see it.

Then one "BIG" step further is to remove the back wall from in between the speakers like I did, leaving a little 1-2mt behind each speaker for bass loading, and then hear and see your image depth go back much further to the back wall of the next room.

Cheers George