hey Collin, have you been able to check out Flickenick's TOTL shootout? that's probably one of the most informative and well written thread about reviews and audio criticism in general. I believe he's written about soundstage and perception on the Headphonelist webpage as well.
here's my take.
consider a bird's eye view, and that you're pretty much a dot. on some instances the dot can be placed inside a box or rectangle, and in other experiences placed outside of the box at a distance.
even when placed in the "box" of sound presentation, you can either be in the snack middle of it,or perhaps most sound either come no past the sides or some have slight sounds coming just "behind" your ear.
now, this is my experience, my perception so Ymmv.The singer may either be placed elsewhere in the "box/rectangle". Depending on mid emphasis as whole (spectrum), female and male singers can sound distant, forward, or "just about right".People will have different standards on this.
I've had one of craziest experiences so far with the Flc8s/Shanling M2/Alo Rx trifecta: you get two layered box soundstages. immersive and holographic. If some agree and others are in disbelief, I invite them to try it lol.
Anyhow, before I ramble on too long, my wife beckons me lol...
lastly, you have Android based apps that can "mess" with soundstage giving a 3d surround feel too. "Poweramp" would be one example.