The loudspeaker requires corner loading for proper use, yet the Stereophile measurement were made outdoors. I don't imagine the frequency response graphs represent what the loudspeakers would sound like in actual use.
Klipsch K Horns (the new AK6)
At $15k, eeek!!!!! and their hard to drive, forget your 2A3's on these
https://www.stereophile.com/content/klipsch-klipschorn-ak6-loudspeaker-measurements
Cheers George
https://www.stereophile.com/content/klipsch-klipschorn-ak6-loudspeaker-measurements
Cheers George