Ok, first I assume the full range drive is not the Harbeth in the measurement.
But from my very noob intrepretation in this graph, the bass isn't really lacking in the Klipsch, rather it seems that in the upper bass from 100-200hz range there are a few nasty dips possibly due to room modes, where quite some bass music will goes into those regions, I expect that placement/room issue is what actually causing those 10-20db dips. and that the 200-1khz range is considerable shot up compared to the trough in the 1.5-3.4khz vocal range, which likely makes certain vocal sounds something missing or maybe lacks sparkle sticking out. Assumed this measurement is the one with the GR research mod it looks like sensible to me that it feels lacking in something in your impression.
While for the full range driver I guess your placement of it won't be exact as the klipsch so maybe the room modes are in different region or not as severe in the listening position, if someone more knowledgable can chime in would be better. if you get the Harbeth in this setting I would guess it would also sounds like it don't do bass well either