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

ATC. Some of the other speakers mentioned here, regardless of price, add their own coloration or character to the sound.

Dave

ATCs don't sound bright at all to my ear.  It's just that many pop and rock records (a fair bit of what I listen to) are splashy (at best) and ragged/awful through the presence (not uncommon) to totally screwed up overall (sometimes).  I prefer something with a gently falling treble response, which isn't ATC

To be clear, I prefer a specific type of inaccurate speaker, which isn't to suggest that anyone else should.

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).

Audiotroy:
I need not prove my hearing capabilities to you. Nor are you entitled to waste my time proving anything to you, a naked Persona shill here on Audiogon. Are you paid an extra commission to sell them? I'm not entitled to that answer so don't bother.
If @vermeer wants to pm me about any of my encounters with the Personas which are very good speakers overall, I'll be happy to oblige.

Easy - studio monitors like ATC SCM 50, PMC MB2, Grimm LS1
consider active versions - best bang for buck