What is the best way to tame a slightly bright speaker?


I know the answer is get a speaker that isn't bright,  but I've got a pair of TAD Evolution Ones that I like quite a bit except that the magnesium midrange and beryllium tweeter are just a little bright for me.  I'm driving them with a D'Agostino Classic Stereo, which I needed to drive my old speakers but I don't need all that muscle for the TADs (89db sensitivity, 4 ohm impedance {doesn't drop below 4 ohms}) recommended power 50 to 250 watts. 

I'd like to get  an amp that does voices especially well.  I know somebody posted recently that a subwoofer solved his brightness problem and I may look into that at some point.  Any and all suggestions are welcome.
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I own the TAD Evolution system with the E1s, C2000 pre and M2500 stereo amp. Source is Aurender N10 going Nordost Heimdahl 2 AES to the pre. Everything is connected to three dedicated lines via older PS Audio power cords, amp to the wall and other gear into an older Shunyata Hydra 6. Room was recently updated and all walls are still bare of wall hangings at this time. E1s are about 2.5' off rear & side walls and are around 8' apart. Floors are medium density carpeted. Sofa is cloth and about 10' away and five feet from sofa to rear wall.

In my room, I'd say that the sound is never bright unless the recording is subpar. There is plenty of snap and sparkle when the recording has it. I've been listening for a few months with very little setup performed so far. My dealer will come around when I'm ready and we will finish dialing them in then. Speakers are toed essentially to the center of the listening position.

I've heard the E1s with Luxman, Pass, Burmester, and maybe one other I'm forgetting. I preferred them with the matching TAD gear and voted with my wallet. I can't remember them sounding bright but they are very revealing and realistic. I'm no speaker setup professional, but maybe toe them in a bit to get rid of sidewall reflections. Play around with pillows and blankets to see if that may help as well. I've also used some plastic vases my wife had in her office to good effect.

I have heard the D'Agostino Classic Stereo amp but not with the TAD gear. It was with the Wilson Sabrina. My take was that amp was like a vice grip with mechanical-like bass control and the midrange/treble was nice but it was not of the usual refinement of the other D'Agostino gear I'd heard and I guess at the lower delta it shouldn't be. I wish I could add more but I just don't have any experience with your speaker/amp pairing. You didn't say what source you are using but that may bring the brightness you are speaking of. Good luck in your journey; I hope what I've described may be of help. IMO, the TAD E1 is very fine loudspeaker.
Tubes or class A amplification. I heard those speakers with an octave tube integrated and I started to cry. I hope you will also. 
Often that 300 a side SS Amp is clipping a lot more that you might think .Micro-seconds sound harsh .
Thank you everyone for sharing your ideas and experiences.  There's a lot to try in your suggestions and I'm sure something will work.  For fellow Evolution One owners, yes they are really good speakers.  I'm looking forward to getting them sounding their best (or close anyway).