here is my SWAG based on my experiences. i've heard Wilson speaker tweeters sound bright, and relatively smooth, but not really all the way spot on butter smooth. and for me this is likely an issue of bass integration, and the various degrees of it happening. Wilson's mostly have 'big' bass, and fast bass, but absolutely seamless bass integration escapes them for whatever reason in my experience. mostly the better bass integration with recent Wilson's i've heard was with the lesser models....just less bass to have to corral. or some nice tubes to cover them up a bit.
with my personal Evolution Acoustics MM7 set up experiences i found that integrating my bass towers after 6 weeks of working at it brought me the smoothest and most extended natural highs i've heard. and it was interesting while i was going through the minute adjustments to the bass towers (which crossover at 35hz-50hz) when i would shut off the power to my bass towers to see whether liked it better on or off i noticed very clearly that the highs were much more complete and natural with the bass towers on and got better and better as i reached the point of complete bass satisfaction and seamless integration. perfect bass overtones complete and balance the highs.
it might also help having deep bass extension and even sealed box bass. my bass towers are -3db @ 7hz and -6db @ 3hz....on paper.
this is not to say that Wilson's are not integrated objectively; it's simply not their best thing, and other speakers are maybe farther down that road. or maybe that Wilson's need a perfect set-up and mature system to find that point.
like i said; this is a scientific wild ass guess. YMMV. maybe i'm dead wrong.
Generally see where you are coming from. Having owned the original Wilson X1s and now the XLF which was the first iteration to inspire me to upgrade...for a consecutive 14+ years now, I would say:
- David Wilson's original design goal was to enable his speaker to be adjusted in-room all across the world in different rooms and systems to accommodate room, system and taste
- Each of his upper modules move back and forth, tilt up and down, and have changeable resistors
- So set up becomes either a complete mess, a mediocre experience...or quite an exceptional one
- The key is exceptional is not necessarily about an internalized, fully consistent sound in an of itself...but rather a speaker that is designed to flex around other variables outside of the speaker designer's control
- And so I would generally agree that Wilson speakers are not in and of themselves necessarily the absolute pinnacle in a particular frequency category or characteristic category
- Where I find them really good is that [in the right hands...where here in the UK, Pedro is not only exceptionally well regarded, but where he is flown all over the world to do setups as probably a 'top 5 in the world' according to Wilson] the Wilsons create a great balance of music making:
- excellent level of detail as reflected in how often you can hear minute upstream changes
- excellent macro dynamic scale
- good micro dynamics
- balanced overall presentation which I have been able to settle into over time...where even if, in comparison to a given other system, I notice differences or betterments with that other system...when I come back, I can easily settle back in because the overall presentation does not have any issues which stand out as awkward from the rest
- On bass, I would say that the Wilsons CAN benefit from properly set up subs and in our case, has worked very well in our room with a single Velodyne DD18+ operating below 38hz.
- To your point, I absolutely believe more can be done within the sub-40hz range, and that is probably my next major move...increasing the surface area of sub-40hz cones in the room by several times to create a more effortless, low distortion and ideally more detailed/nuanced sense of venue, and as you say, possibly also creating a better side effect in the mids/treble