Klipsch K Horns (the new AK6)

I read the review and there are obvious issues like the front panel resonating and the phase distortion between drivers. I would love to triamp K horns, and correct the phase issues and frequency response with DSP control. Add subwoofers below 100 Hz and I bet they would be in serious contention for best sound ever. 

I too am a bit surprised that a high efficiency speaker like these would have such a dubious impedance curve. As to the other peculiarities, these should come as no surprise to any hobbyist that has even a elementary knowledge of this design. 

High efficiency and load are of course two different things.

Getting a good match is always critical but the speakers that will work well with the widest variety of amps are those with an easy load, like Daedulus and Fritz, not necessarily those that are high efficiency.

Efficiency only determines how loud things can get per watt.

An easy load also means "better mileage" per watt which can translate to speakers going louder better than others with difficult load yet similar efficiency specs.

High efficiency speakers often get a bad rap because they have potential to easily sound the most wrong if not driven by the right amp. But with the right amp....... Not for the faint of heart.

Had a pair of LaScalas in a huge living room powered by a custom made SE EL84 amp from Don Allen- RIP. Kicked a-- on anything from solo guitar to jazz trios to symphonies to rock. FWIW.

mapman,

I dont disagree with anything you wrote, but often it is the higher efficiency speakers that have a higher and more stable impedance curve for use with tube amps.