measurements of FR give you the tonality info, horizontal directivity gives you the soundstage width/imaging depth info, distortion/compression tests inform you how much of the signal is clean/true to source and how much oddities the speaker is producing.
Not rocket science or anything. The Salon 2, like other Revels, likely has a ballooning directivity that sounds wide but not as precise. If you want to hear something similar to your JBL's, based on what you're saying you can buy a pair of Ascilab speakers, Genelec The Ones, Neumann KH series stuff or Any KEF.
Look at this and see how i can draw a straight line on the genelec whereas the revel goes up and down. Everything is consistently placed on the genelec, soundstage is consistent and will feel "deep".
View attachment 501921
Some examples from JBL themselves, 4329P and JBL 708i
View attachment 501922
When JBL wants they can make razor flat, nearly textbook perfect speakers in terms of directivity. Just 2 examples here. Just seeing these graphs makes me salivate at the soundstage depth. I've tried wide sounding speakers and narrower stuff and I'd take these speakers with depth any day of the week. You close your eyes and hear a snare, and feel like the reverb goes out into a black hole.
I doubt you're hearing this exact thing tho, considering the lack of a waveguide i doubt the speakers you're listening to are so perfectly controlled but if they are, that could explain what you're hearing. If not then you've just been duped by your brain and you wanted to stir something up here