I listen to almost everything except reggae,r&b and jazz. Sibilant or ear fatiguing? No. Sharp with some recordings,yes. However the in room response I measured with REW shows that the treble doesn't roll off much and is elevated in comparison to the upper mid range which shows a dip in my room's response. Now whether that's due to vertical listening height,speaker placement,reflections,or something else I'm not sure.I am guessing that it has more to do with my room which is small,almost square and the sidewalls aren't symmetrical,and possibly placement or seated listening posistion.
The vertical listening window is also pretty narrow for the RAAL version. I believe the tweeter is the reference point for the ELX and is only 33" off the floor. My seated listening height is between 40"-43",so it could be causing the upper mid range dip. My solution for recordings that sound sharp is -1 or -2db on the treble tone controls.
Edited to add that these are the best speakers I have ever heard,the dispersion,imaging,dynamics,bass response tone and texture,and cohesiveness in the soundstage is all excellent. I don't want another speaker. These are it for me for the foreseeable future,unless I come across a deal on the Titan version and even then I would probably keep both.