Nola contender tweeters - modify?

Bright/harsh when played loud...see reviews. Tweeter issue and/or caps, resistors etc? I'd really appreciate opinions on how to solve the problem, particularly if it's cheaper than new speakers.

Accompanying equipment: VAC Standard 160 MusicBlocs (4 kt88s, 7sn7,12AU7 per amp), Sonic Euphoria PLC, Basis 2001 turntable w/vector III and AT Art9, Rogue Audio Ares w/upgraded transformer.

This sounds more like rom acoustics, or lack thereof. 

Try throwing some blankets/pillows around on the floor behind and between the speakers. I find this often greatly helps with treble hash. 

But your whole room is important. 
I have considered that as a possibility yet haven't done anything about it to date. Good suggestion, thank you.
I cannot imagine, having owned 4 or 5 models of Nola speakers, that tweeter harshness is likely.
I have Contender 1s, and I’ve never heard them sound like that - except for when they were first breaking in (weeks of continuous play, which you would have achieved by now.
You didn’t say which version they are: I, II, or III. And are they new? Because new, they can CERTAINLY sound a bit bright. Otherwise....rather unlikely.
I agree it with the other poster, that it  would be something over than the tweeter, such as room acoustics. I doubt there would be an electrical mismatch between the VAC and the Nolas.
safebelayer, May I suggest a Bijar? The iron rug of Iran.