A very fair question for anyone who doesn't follow my warped, convoluted thought processes. 

It was in the context of a discussion we were having about his 'Layered Sound' approach. Basically this is where you use NXT-type flat panels alongside conventional moving coil speakers but at about 5dB down.

Dr Katz believes that this gives a more realistic impression of a musical instrument and, as he's a classical pianist of some repute, I felt that I should at least listen to what he said.

I was saying that NXT panels were pretty grotty, mostly in terms of of their frequency response & sound decay characteristics and that I wouldn't want them in the same room as my precious Nonsuch 4s, let alone in the same cabinets. He said (and now we get to the point) that this grottiness didn't matter as the reverberation and reflections were basically dirty. Also, that the non-instantaneous decay in these panels gives a more realistic impression of the live sound.

BTW, if anyone's interested in experimenting, he reckons that the Fane Micro Pro and Mini Pro DML panels are amongst the best.

(Since you asked)