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

For your budget, used Raidho may worth your consideration. 

I always wonder what is meant by accuracy. Accurate to what? I am a recording engineer. Do you want it to sound what it sounds like in the control room. Remember the control room doesn't sound what it sounds like in the studio. Accurate to the sound in the mastering booth? Accurate to the sound on the digital file. Digital file played back on what system? All speakers are colored which means they add there own characteristics to the sound being sent to them. Find a speaker you really like and go with them. Pretend they are accurate
Alan

@2psyop Vandersteen is a very forgiving by amazing speaker. You could save some money and get the Treo, and invest the delta in room treatment. That will most likely be a better route to go.

@ahendler I interpreted "accurate" as flat response. That was why I originally recommended the Decware HDT. That said, potentially time coherency is more important that completely flat response to the OP.

End of the day, I fine that many Hifi speakers tend to be more forgiving, and more enjoyable to listen to but they also bump up the treble quite a bit. I think many mfg. know that as age increases, the ability to hear HF decreases.

That said, I am always blown away when I listening to a pair of Treo's or Quatro's.

Focal Utopia with Nagra should be able to give you what you are looking for. Speaker cables would have to be carefully matched. Many use Utopia with tube electronics, though, it has a tendency to be a little bright.