Is soundstage DEPTH a myth?

                             How LARGE do you like your music?

     Unless a system can cleanly reproduce all the information (well engineered/recorded in an environment with good acoustics and mic placement) in a quality cut, to the original/intended dB level; It's listener will never hear that information.

              ie, regarding, "depth": the reflection off the venue's back wall.

      Of course: familiarity with the venue in which a recording was made,  would go a long way with regards to recognizing whether what one's hearing is actually accurate.    NOT that that's a necessity, when it comes to the enjoyment of one's music, BUT- having that knowledge, one can be confident that their other recordings are also being faithfully reproduced.

       'Checkerboard Lounge Live Chicago 1981' (on vinyl) is a favorite of mine, far as being able to hear the room, especially between songs.

        Especially, in the softer cuts of Diana Krall's 'Live in Paris' vinyl (45 RPM/180 Gram), I find the Olympia Theatre's back wall reflections nicely reproduced (with accurate depth).

         Back the the size-of-your-music thing: I turn my sound up slowly (a song at a time, to acclimate the ears to higher dB levels, without having them shut down), until my image height reflects where I imagine/know the performers to have been, when recorded.     Again: a system has to be able to reach that level cleanly/without distortion, or: it's just LOUD (iow: noise).

          It's been my experience: seated in the better/more expensive, front and center seats; it's easy to hear and locate individual voices (human or instrumental), on a stage and seldom would the level be low enough for some to consider, "safe enough".     Yet: no one complains, because it's clean sound (just big).

           Most Blues are just meant to be played energetically.

           Ever seen anyone cover their ears during the Finale of Stravinsky's 'Firebird'?     

           The long pipes/pedal notes of the Crystal Cathedral's Ruffatti organ could/would pull the air from your lungs.     Playing Crystal Clear's DTD recording brings that home.

            It's also during such reproduction, that the effects improved fuses, PC or speaker cables and interconnects bring to the listening room, are most evident.

            The tests I mentioned in my first post eliminate all the variables and present the listener with established sounds, that will let them know if their system is actually reproducing what's in the recording.

             If your system doesn't put out (or you can't hear) what's in those tests: it's NOT because the effects are a, "myth"!

The answers from you guys are, yes soundstage depth is real. The only question left is would people experience it regularly or with just a few rare pieces of music?

Because of what I listen to, I recognize imaging, soundstage and depth most always.  But I'm sure I tend to favor recordings with those attributes.  However, most of the tracks in my 100K plus library have those attributes. 

Imaging, soundstage and depth are a result of the recording engineering and of course, the type of recording it is.  Listen to some well-recorded jazz or live jazz -- and that is most of it -- you can hear the room, the audience and there is depth and a sense of the room.  The same can be said for symphonic recordings and many studio recordings.  Soundstage and depth provide a sense of being in bar, the recording studio, or the symphonic hall.  Without the you-are-there attribute, my Alexa speakers would be sufficient verses my Klipsch, Martin Logan and SoundLab speaker rooms.

Don't listen to @audioman58 . 

You don't have to to spend that kind of money to get soundstage and depth. 

I wonder if rear fireing speakers ( often a midrange driver ) could help,
perceiving depth ?

I have Audiovector R6 Arrelé  and I do perceive depth .

As I mentioned in a earlier comment in general the more $$ you can spend per component the closer you can get to your audio nirvana .your records yes willhave a bearing on the depth also but if you have  agood balance in quality including 

quality-digital cables then you will get a fair amount of audio realism on a daily basis . Just expect to spend a minimum of a bare minimum of $20k to start 

for a respectable sounding system , and upgrade pieces as you can afford .being aAudiophile can add up $$ very fast.