Hey Dan,

I have Sierra 1's as my LCR. Just got them this past July. I upgraded from old Boston Acoustics CR series from the 90s. It was a huge upgrade in 'fullness' of sound, especially male voices, and dialogue intelligibility. I have them all crossed at 80 htz. I have not heard the NRT tweeter or your Def Tecs to compare, but I would be surprised if you're not happy with dialogue intelligibility and clarity with the standard Sierra 1.

I listen to music more now than I ever have because it sounds so good! I listen in stereo with the sub and it is so much better than the old Bostons. They couldn't image at all, ha.