From whence does Sound Stage come?

@rodman99999 Thank you very much for the links to the AudioCheck site and the Chesky CD. I shall follow up on them. I started with the ‘More’ articles, first I’ve heard of LEDR phenomenon and testing method. I noticed in my reading of the article in Stereophile that two items negatively affecting sound staging can be found in my system: bi-amping (phasing) and B&W 801 speakers (vertical dispersion)
I should add, for the benefit of you and other readers, that the sound staging of my system became an issue since I have started bi-amping my speakers, particularly the B&W 801 Matrix speakers, their vertical dispersion quality doesn’t bother me as much, but it does explain why the voices are coming from the top of the wall where it joins the ceiling.
My two current systems are described in detail in my virtual systems, although I haven’t yet found a way to navigate to either my ‘Temporary System’ or my ‘New System’ except through my own Profile page.
In brief, the Temporary system (downstairs) from Room/speaker to source: 11x11x7.5 w/4 doors (the junk room, that still has a lot of ‘junk’ in it), B&W 801 Matrix, (2) RadioShack 250 Watt PA amps bridged to mono capable of delivering 350 Watts at 1kHz into each speaker over Channel A, (future plans call for hooking the Warfedale W70E’s up to Channel B), McIntosh C100, Schiit Yggdrasil LIM, Madrigal Proceed CD player (the Toaster). The New System (upstairs)15x19x7.5 (with the rear 7’ over the staircase in a split-level house), McIntosh XRT20 Isoplanar Loudspeaker System with tweeter columns are mounted on wall at the recommended 1/3’s (5’ from each wall and 5’ from each other, credenzas are two inches or less from the front wall and 8-9” outside the tweeter columns, again, as recommended by the manufacturer, (2) McIntosh MC252 power amps, each bridged at 4 Ohms to deliver a maximum of 500 Watts to each speaker whose impedance has been verified at 8 Ohms or better (not falling below 5 at 10 kHz), McIntosh MQ107 Room EQ set flat with a boost in the lower frequency of ‘2’, Schiit Freya+ using single-ended outputs to take advantage of the MQ107, (1) Oppo BDP-105D balanced line into Freya, with optical input from Samsung UHD TV, and SPDIF output (both optical and Coax [the last is not strictly necessary]) to Onkyo 1513 AVR to a pair of Realistic ported 10” two-ways, an RCA center channel, and Velodyne miniVee subwoofer, (2) Elac PPA-2 using balanced line into Freya, Music Hall MMF 5.3 belt drive with Sumiko Songbird high output moving coil cartridge. (I guess that wasn’t so brief.)

Anyway, as you can tell, I’m experimenting to see if ‘more power’ will improve matters (ala Scotty to Kirk, or Tim “ The Toolman” Taylor). I have been rather stymied by the 87 bB efficiency of the McIntosh XRT20’s, but that is a topic for a different thread. Turntable has never sounded better.

Edit: Downstairs I stream through an original Auralic Aries with their linear power supply; upstairs I’m listening to Pandora through the Oppo player/DAC. I have yet to sign up for a service, but I have a renderer and My Cloud NAS with CD attached whenever I figure out how best to create a library. 

I might also add that I have limited test equipment available: a frequency generator and analog oscilloscope, the DATS V3 Audio Test System for component testing, and a miniDSP UMIK-1 microphone, boom mike holder, and the free-to-download Room Equalization Wizard (REW) software package which I’m currently learning to use. 

@rodman99999 After thinking 💭 over your response and pondering the content you referenced, the answer to the original question, ‘From whence comes Sound Stage?’ The answer might well be, ‘from inside your head’ (not yours of course, but mine, or any listener). In other words, it is a psychoacoustic phenomenon that system configuration, component selection, and room treatment can either enhance or destroy, and that is different for every individual. Amazing, when you think of it. It is possible for me to tune my system and room to near perfection, yet you might miss most of what I enjoy; and I likewise for your system. May be the reason I’m drawn to this hobby. 

Most of the time my laptop sounds like they usually do. Every once in a while I come across a YouTube video with music that makes my laptop throw a soundstage. It really is quite remarkable. This makes me think: exact same speakers, in exact same place, with exact same amp, through same internet, YouTube, etc. Only the source changed, yet this alone is enough to throw a remarkably improved sound stage.

You already heard your current speakers throw great imaging. Sometimes, anyway. Sometimes. Just like my laptop. Since they can do it, then if this goes away it must be something else. Main difference being, in a laptop everything stays the same except the whatever it is you're playing. With your system, in brief, you got a whole 500 word paragraph of things that can change. 

The laptop proves its the source that matters. In your case, everything feeding into the speakers can be thought of as "the source". 

@edisoncarter Point taken. My friend in whose house I first heard a decent sound stage tells me I need to use better sources. Thanks for the response.