>>You can't seriously expect these speakers to be accurate.<<
Yes, you can. Look, it's simple: Druid's design *requires* a floor immediately beneath the speaker for it to operate correctly. Changing the floor gap by millimeters alters bass response and if it is set up wrong to be too tall, the midrange can begin to be affected. Dial it in right, and Druid's tonal response smooths out. Within a practical adjustment range, the floor gap can be used to tune bass response to room characteristics or subtle specific user preferences. The speaker in use sounds nothing like the graph from Soundstage's mid-air test.
Essence, Superfly and the Omen series also have varying levels of Zu's proprietary acoustic impedance loading scheme that open the cabinet to some degree on the bottom. All have been engineered to sharply reduce the floor gap sensitivity that was elemental to Druid, with Essence specifically having a double plinth to enforce its own "floor."
Definition 1, 1.5 and 2 were sealed cabinet speakers. The upcoming Definition, Experience and Dominance models do not vent through the bottom, so floor effects are not a factor.
If you set up a Griewe loaded Zu speaker correctly, it will test and sound like the relatively neutral speaker it is.
Phil