Veiled 'wet blanket' sound from tweeters

I have a tough time with that one for me, too. Speaker are the ultimate in sound OFF my head.. LOL. Head phones  can be good, but they wear me out, no matter how comfortable... I just like digging the detail out of floor standers, mid field.. med size room.. 16X20X8 or 9 is fine.. I like to be able to hear outside the headhear too. JUST in case something is going haywire..

YUP 5 X the cost for the same small setup, have to be careful, it could be 10 times that in a quick second.. :-)

Have to get the, the "Titian of tinker", "Most for the money" Mahgister  to ring out a system for you, LOW cost HIGH quality.. LOL I love when he chimes in... He was an avid HP guy, too.. Likes his SQ.. no doubt..

Regards

Get a DEQX premate or an Anthem STR. They will show you what the problem is and correct it. The speakers won't have quite the detail of headphones but the will sound a lot better. If you want the detail of Headphones in speakers you have to get ESLs.

try try listening to the speakers in a small, say 3’x3’x3’ triangle with speakers center of room pointed directly at your head. Thats as close as you can practically get to replicating cans on and the direct sound should let you listen to tweeters also download a free db meter and run a 20 to 20k Signal from tidal.

Another possibility is bad ferrofluid fluid in the tweeters. I had that problem with my B&W P5 set after about 10 years. The condition you described is very similar to my experience. I had output, but it was extremely limited causing the speakers to sound lifeless. 
I removed my tweeters from the cabinet, then lifted the diaphragm gently off. I used some alcohol to clean out the old fluid that had hardened, then replaced some fresh fluid from Parts Express. That brought them back to life again. 
Good luck!

+1 nicemix

Only caveat is that it is my understanding that some tweeters are harder to pull the diaphragm than others.  If difficult, suggest you call Bill at Millersound.