My two cents:
- I have owned the SF Guarneris and the SF Strads, and now the Wilson X1/Grand Slamms. I have heard both the SF Strad and the Wilson X1s in my home in the exact same system. Setting aside all of the differences elsewhere between the 2 speakers, on the treble, i think somewhere in my 'review' i noted that the X1s remained shockingly close to the Strads. (The mids believe it or not were even...i was MOST happy about that!) But in the treble, would i say my ears can tell the difference? Yes, particularly on older recordings of violin...but for my ears, they are distinct but close for someone whose priority is mid, then bass then treble. I might rank the X1 at an 85 and the Strad at 100.
I have to give credit to the Distributor who set them up...we went thru 3 resistors before getting it to my liking. And Wilson considers him one of their top 5 go to guys for setting up systems. I also have Zanden digital front end, CJ and Gryphon electronics and TA Ref XL calbes...so that ameliorates it, as Martin Colloms has noted in his review from many years ago when he also found CJ to work very well with the X1s.
For me, who perhaps is not as sensitive to some to tweeter issues (midrange and then bass matter more for me)...yes i can tell the difference and favor the Strad...but its darn close when set up well, such that the difference in recordings is far bigger an issue than the tweeters...and further, such that the rest of the X1s attributes for me worked much better.
REgarding the XLF tweeter which i have heard on 3 occassions, it is wonderful. I would love to hear it in my system, but frankly i dont need to...i have heard those speakers with equipment that i have done auditions with, and also in the same store. It is a very nice change for Wilson imho.