What causes listener fatique? cure?

I guess we all have different interpretations on things. I am glad you like the Focal Ti tweeters, Sedond. While I simply love the woofers/midwoofers/midranges from Focal, I absolutely abhor their tweeters. Be they Ti, TiO2, or Kevlar. The Ti in particular are the worst sounding tweeters I have ever come across. Perhaps in your speaker, the designer was able to make them listenable ala the crossover design or whatever. I have not encountered any listening fatigue in drivers operating above their ideal frequency range OTHER than metal coned drivers. The metal drivers are quite succeptible to audible, irritating ringing.

As mentioned above, I agree that there are many different things that can cause listener fatigue, and I've found it's usually electronics, wires etc. too. John_1 has a good list, But one more: as the tubes in my pre-amp reach the end of their useful life, they produce brighter, harder upper mids and low treble that give me headaches. Of course putting in new tubes takes care of the problem-- it took me awhile to figure this out though. Non-fatiguing speakers between $2000 & $4000?-- I'd nominate Vandersteen 3Asigs. at $3500., or std. 3As at $2800. Good Luck. Craig.

I second the Harbeth C7 ES! This is an especially true speaker, designed orginally for BBC engineers who have to listen for hours on end as they master their recordings. I have only had mine for a few days and they are incredible even in this early stage.

I think vandersteen's have metal dome tweeters do they not ?
I know the five's main forward tweeter is metal & I think this is the same one used in the 3aSignaure. (the fives rear tweeter is a silk-domed vifa). I do completely agree that the entire vandersteen line is non-fatiguing. The audio physic virgo is also a metal domed tweeter speaker. It is non-fatiguing with good source components.

Room treatment is another possible cure.