Jonny,
Have you listened to my speakers? B&W 805’s with their diamond nautilus tweeters??? LOVE THEM!!! Perfect for my townhome(neighbors), as they aren’t floor standers, either bookshelf, or on stands, as I have them. Non-fatiguing, listen to them all day long! Sounds like the band and singer are in my room with my eyes shut!
Took a while to break in. Played an endless loop of albums while I was at work, to speed up the break-in period. Wonderful!!! Beautiful construction, and they look so damn cool with the speaker covers off. Put back on when I’m done to protect the drivers from dust.
I thought of another way to kill brightness and sibilance, was maybe a speaker with just one full range driver. No crossover, no tweeter, no mid or woofer, just one driver. But cannot find anyone demoing/selling them, except online. And the prices made my speakers seem cheap! But would love to see how they sound and image. No idea. But an interesting concept. No idea why they cost so much. That single driver must be a hell of an expensive piece!! This is an EXPENSIVE hobby I love!