I am a ZU distributor and believe I can shed some light on the discussion. I also distribute a couple of award-winning speaker brands, highly regarded by the press and owners. Those other speakers are 3 way, with 12 db and 6 db crossovers.
Each speaker sounds unique and each is the right speaker for one consumer, maybe the wrong speaker for his next-door neighbor.
First, anechoic measurements are fatally flawed in terms of predicting the listening experience.
There are a few reasons:
Some audiophiles listen with a detail-oriented, HI-FI-ish mood and pay lots of attention to frequency response, soundstagind, detail and colorations. The most reliable measurement that I know to assess HI-FI "behaviour" of a speaker is room-averaged response from several mike positions.
However, there is no universally accepted standard to measure in-room bass.
If a speaker looks bright or boomy in those room-averaged graphs (like JA does for Stereophile), it will (in my experience) sound bright or boomy in a typical living room.
However, that's in-room frequency response, only one of many speaker performance yardsticks.
Music is not made of frequency response only.
Live music has rythm, pace, timing, tone, DYNAMICS, emotion, a believable soundstage and coherence. Most of those atributes are impossible to measure with today's measuring equipment. Maybe dynamics can be measured.
Another school of audiophiles (or may I say mélomanes, excuse my french), do not usually give high priority to frequency response. They care about the emotion, the gestalt of the music, an experience that reminds them of last week's concert, as opposed to a ruler-flat response. That's when an attempt to discuss full-range drivers in scientificv terms fall into a loophole. Frequency response and ripples do not explain why these drivers convey so much of the musical experience, rythm, pace, timing, tone, dynamics, emotion, soundstage and coherence.
There is seminal paper published by a japanese designer (he works for Mitsubishi and designed a single-driver speaker recently reviewed on a major magazine, Absolute Sound or Stereophile, memory fails me). If any Agon member has the link,please post it, I have not found it while writing this. His thesis is that speaker design should be focused on impulse response, not frequency response. The paper has a few graphs that make a lot of sense and helps explain why so many response-oriented speakers fail miserably on musical transients and sound like three different voices, not one voice.
In summary, if you crave for music and tone, there is a high probability that you will enjoy Zu speakers (or Lowther, Fostex, etc., though those sound to my ears more like an attempt to bridge the gap between tone and frequency response).
Adam and Sean deserve greater recognition for achieving GREAT tone within a reasonable budget and FOR NOT fallling into the frequency response trap.
I have opened up my ZU speakers. The cost of achieving HI-FI-ish frequency response is just a a couple of caps and resistors in the crossover, however making those changes will throw out the baby with the bathwater. I know from hands-on experience. Just for fun, on a rainy weekend, I calculated a theoretically frequency-perfect crossover and installed it on my personal Druids, then measured them with a 31 band real-time analyser...great treble, lots of detail, smooth midrange response, but the additional reactive components killed tone and coherency when listening to music, not test tones or pink noise.
In summary, Zu speakers convey a different musical experience, which may take a few days to get used to.
Once one gets used to them, HI-FI speakers sound unrealistic, constrained in dynamics, tipped up and not coherent.
Others may never like Druids and I respect those opinions. Spouses, shoes and speakers are very personal choices.
IMO, most of the advice in this thread is correct, however there are a few misunderstandings:
-measurements do not tell the whole story; science is no substitute for a test drive (says Porsche);
-most speakers are measured on a specific axis (that's the frequency response you see on the marketing brochure)... off-axis, most will have A LOT of ripple due to dispersion anomalies, refraction, cabinet edge difraction and frequency beating/cancelation between drivers;
-the Druid's internal path length is about 40 inches, the cabinet height;
-The Druid is a slot-loaded speaker, not a tuned pipe;
-yes, its bass varies with room placement, however, it changes mostly in bass quantity, very little in bass quality, as compared to resonance-based bass alignments. Four inches can make or break a bass-reflex or passive radiator speaker's bass. It may sound too lean or boom unbearably.
The Druid does not change much its bass quality from 10 inches away from the back wall to a yard or two into the room. Also, IME, it does not boom or resonate in the bass, unless one uses a poor amplifier or bad recording.
In summary, the advice given by several posters: try them and if you like them, keep them...is sound advice (pun intended).
Enjoy the music!
