I own the CDM-1nt's. This is what I've found:
I don't know how long yours have been broken in, but mine seemed to take ~3-5 months. At first they were shrill and bright, presently they are smooth and warm. My wife noticed the difference.
I tried felt and this seemed to work but not as much as I would have liked. The big difference for me was:
1) Moving the speakers further apart ~8 feet and using less tow in. This made a unmistakeable difference.
2) Changing the power cord on my Rotel RA-1070 int. amp to Volex 17604, 14 gauge/shielded (cheap ~ $5.00 thru Newark.com). I plugged the cord directly into the outlet bypassing the surge protector. This was not insignificant it was HUGE! (I was not a believer in power cords). The sound became warmer, bigger, and the bass is now much deeper. I then changed the cord on my CD with the same cord, bought two. This helped as well but not as much as on the amp.
Hope this helps.