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.
128x128tomcy6
If you want to see without as much work with rectangle cut out. Go to drum shop and buy dense felt cymbal washers ( they go under and on top of cymbal on cymbal stand, much better quality felt than at fabric store)cut into four pieces and blue tak around each tweeter.

If you want to experiment with tube components investigate tubed preamps.A smooth,warm sounding preamp such as Conrad Johnson units for example might add just enough sweetness to tame that brightness.Then experiment with various tubes until you get your system tuned to your preference.
Room treatments. 

Toeing then out out a bit to get to where the tweeters roll off could help too if it does not mess with other things too much. Just have to try and see. It is free. 
Jim Smith Book on better sound, felt, revisit excessive toe in and or tilt, room treatments and then hardware changes

No joking the Zobels networks I have advertised in Loudspeakers will reduce the upper frequency noise and your system will sound better .if not  money back .i just spotted this in the forum .
that  is the easiest way ,or you can solder  in new capacitors.