Zu Druid MK IVs vs. Essences

Ears trump lab results.

However, ears might also need cleaning or some education. In the land of the blind, the one eyed man is King. Just because a few people like something does not necessarily make it wonderful sounding. A bass guitar woofer in an aesthetic audiophile cabinet...mmmh.

Druid's design *requires* a floor immediately beneath the speaker for it to operate correctly.

Is that all? Those measurements suggest way more issues than that but as Charles1dad points out - it is all in the eye (ear) of the beholder - if you like it so what...

Whizzer Cone:

A small supplementary cone attached to the voice coil of a speaker for the purpose of producing and radiating high frequency content more effectively than the larger speaker cone. A whizzer cone is attached to the voice coil in the same place as the speaker cone; however, where whizzer cones are used it is necessary for there to be some additional flexibility in the joint between the speaker cone in the voice coil. This allows the speaker cone to become somewhat decoupled from the higher frequency motion of the voice coil so it doesn't dampen the voice coil from being able to move the whizzer cone at those higher rates. Whizzer cones have fallen out of popularity in the last couple of decades, mostly due to the added coloration of the signal produced by the necessary slop in the coupling between the speaker cone and voice coil.

The impedance and frequency plot shows that the Zu Druid is a Paul Voight type design.The notches in the bass are caused by line harmonics cancelling the output from the drivers front. The distance from the floor will make a 3 dB difference at certain frequencies but noway nohow can this explain a 20 dB notch. The erratic response in the midrange is likely due to the whizzer cone.

I respect your opinion, but really that`s all it is

Agreed. Same goes for me and Dock's comments about the measured response. Just think of it as a service to prospective buyers and the OP - to be aware of some of the limitations of the products under discussion. Perhaps Bjesein might not have lost $600 if he had been forewarned here on Audiogon and been able to make a more considered or informed decision.

FWIW - these speakers do wonderfully well with a flea powered amplifier. They definitely have some major advantages for some.

In Druid there is no interior taper and no progressivity in managing the rear wave.

What you are suggesting is that it is even simpler - a quarter wave pipe.