Taming bright Thiels


I have been attempting for months to find a way to tame the brightness on my 2.2's. Ended up with a crudely simple short-term solution after much tube and cable rolling and equipment fussing (System is Theta separates, ARC LS2b preamp, Rowland 1 amp, Harmonic Tech cables).
I experimented with taping thin material suspended in front of the midrange driver to produce roughly a couple decibels acoustical attenuation in the 1Khertz to 3khertz region from each channel. (I experimented with 1- and 2- ply tissue, cotton cloth, etc.)
What a magical difference. My wife immediately asked for a listening evening, something she hadn't done in over a year.
So I wrote to Thiel (many times) and asked if a low-value resistor wired in series with the midrange driver would have the same effect with less likelihood of side effects.
While they responded to every query promptly, they absolutely would not give any information on any possible modification of the speaker to attenuate its overly bright character.

Anyone attempted such a modification? Results? Caveats?
hug
Tim, I'm glad you're learning something - I was once young and thought I knew everything, now that I'm older I realize I don't know S#@T. But I do know bourbon and I hope you took my earlier advice and upgraded to Jim Beam Black from Evan Williams...:-)...
Could be your room. But it is hard to treat your room without change its look. I would say change to a not so bright speaker. That's a quick and direct solution. Lots of people already try different electronics and cables(bright & soft/ss & tube). Majority of people can't get the brightness tamed. Blame on preamplifiers or cables seem unnecessary. Usually electronics (include tube) and cable have a flat spectrum compared with any speaker. If your speaker can't perform flat spectrum in your room, changing electronics won't help much. Especially you already try some good electronics on both sides (soft and bright).

So I would suggested either move to better room or change your speaker. Edgy sound may appear "clear" in the beginning but starts to kill your ears min later. Sometimes, people are chasing that "clear" sound by wasting money and time on wrong equippment change.
Some just being lucky to have a soft room, and they have more chances to get good sounds out of your speakers.
Power and current. I under powered my 2.2's, 2.3's and 2.4's until I added a Krell fpb 300 to the 2.4's.
Best sound I've ever gotten, not bright at all. Didn't need to add a tube pre, but I did and it sounded nice, but quality power and current solved all the problems I've ever had with Thiels. The speakers are a bargain, but you have to have power and current or you won't like them. There is no cheap fix. 
I once traded my CS5i's (don't buy a pair unless you can afford a Krell fpb600!) for some huge Altecs powered by some little Quicksilver Mini-Monos. They sounded nice. I listened for a year, then got CS6's with Krell 250 monos and returned to the big, detailed Thiel sound. 
I've always found Thiels to be great with the proper components attached.  Flaws will be exposed.   I suggest something other than your speakers to be the offenders.
I've always found Thiels to be very good speakers that expose the flaws in the chain.   I would look elsewhere for your warts.