Searching for the most "accurate" speaker (below 15K)

@vermeer 

Active ATC are slightly better than passive. KEF or TAD is a good choice too. 

I like the Harbeth mid and the Millenium Excel tweeter they use - among the best mid range. Their thin walled cabinets means the bass is somewhat of a matter of taste - great classic FM radio sound but not great cranked up with rock or large orchestral or big band. If you live in a condo you can't play loud anyway which makes a Harbeth a great choice.

I have not seen a good set of measurements for Paradigm Persona 3F but they do appear to be well engineered.  The crossover at 2.4KHz is actually close to the right place for this three way design (which has a large 7 inch midrange) which is a miracle these days (most manufacturers like B&W get it all wrong). I would really like to see how the tweeter and mid performs on a waterfall plot to know if it is nice and clean from 400 to 10KHz.

At $5000 this seems like excellent value. It seems to be one of the speakers you are already considering. Why not go for it!

Marty is correct. My experience with ATC is they are quite flat but have rolled off treble above 12K. So actually their soft dome tweeters are polite compared to other metal dome tweeters that extend higher.

The main thing with ATC is that the mid range has no dip or scoop. This means distortion and compression in modern pop rock can sound harsh on an ATC compared to the usual scooped midrange of the vast majority of speakers (B&W is prototypical). This translates to a more forward sound (close to the stage) than most smiley EQ speakers with a scoop.

Perhaps this is what Dave means by bright. I think Dave has the ATC 40 which is mid range in ATC domestic range. The larger ATCs actually have even more massive drivers - the 3 inch mid range “super” model is heavy (20 lbs).