Interesting -- thanks for measuring & posting this!
It might (?!?) be interesting to compare a 'high end' analog XO like this to a decidedly lower-budget (indeed, borderline vintage) XO like the venerable ones made & sold for years (for the pro market) by EV. I doubt they'd do very well -- on the other hand they were inexpensive (and are very inexpensive, and plentiful, used) and they're user configurable (
albeit with some 'hands on' work).
I have a 'pair' of one such model (cosmetically/morphologically mismatched but electrically equivalent) that I keep trying to work up the gumption to try on my FrankenAltecs -- although I also keep trying to work up the gumption to try DSP, too.
https://www.electrovoice.com/binary/XEQ-3_Engineering_Data_Sheet.pdf
EV XOs by
Mark Hardy, on Flickr