It has a silkiness, clarity and musical presence that is unlike anything else honestly. I have been A/B’ing with everything vintage/new so there are some familiar places. It feels a lot like an E120 (in terms of power quick response to touch sensitivity). But it reacts to change is pick attack quicker. It also reacts to guitar volume adjustment more dramatically.  So, it is more like a vintage Celestion in that regard. The high end is right there without being harsh… that is the failing of the JBL as you get the harsh sizzle from the metal dust cap among with the clarity and presence. 

If I had to sum it up… the speaker has exactly what I was looking for for my new model: a powerful/responsive speaker with high power American presence and clarity and British “silk” in terms of mid response (as you say in the upper range). 

You guys definitely did a nice job with this one.