I've never heard a spec (but I'm sure someone will say they have). You need to get your ears on some speakers to make an informed decision. Just my humble opinion. Good luck.Start by doing your self a favor and forget about specs - instead use your ears - then consult your wallet.
Dynaudio X12 or 16
B&W 805d
Dynaudio C1 MKII
Focal Diablos
Magico Mini II or Q1
Tad CR-1a Reference
All are excellent but different - price range from 1,200 to 46,000