That's simple. A reference speaker should be Tunable. It would drive me crazy to have a speaker I can't physically adjust to my liking. Why listen to a speaker that one constantly has to blame something else in the system or recording for not sounding good?
Serious audio playback systems are Tunable, the rest...well welcome to the never ending revolving door of HEA. Not me, I'd rather be spending my time enjoying my whole musical collection.
Very strange to see someone having 40 pair of speakers never hitting the nail on the head. That's not a listener, that's a collector. Nothing wrong with a collector if that's what someone wants to be, but there's another way to get the sound you want.
michael
http://www.michaelgreenaudio.net/tunable-speakers