If I remember right they were driven by a 300B.
On one hand it was the lack of box resonance (there was no wood or MDF vibrating to add audible contribution). On the other hand - the bottom extension was very good (probably owing to the 2 15' drivers covering a lot of area). It felt clean, extremely precise and satisfying. I tried to find a fault but could not.
Comparing with other rooms I liked, the Magico S5 felt unreal - as if you'd grown superhuman hearing, and the Pass Labs room (running a vintage set of Tannoy drivers in handmade MDF huge enclosures) felt pleasant, motherly, somewhat imprecise but very easy to befriend and immerse into.
But the Holograms - I could not find any issue (neither scary, endearing or any other flaw).
They were saying that there is NO room correction of any kind. If I remember right (again) - there was a mac mini on a stabilizer shelf on the floor, but they were running analog source from the back of the room. But I might be mistaken about the analog (too many rooms...).
Thanks
C.