Anyone listen to Zu Audio's Definition Mk3?

I agree 100% but couldn't you get into more detail; just kidding. The Mk4 is a total different level than the 2 or 3 and it should be at the price point they sell for. I will say that after owning a ton of speakers I don’t understand why this speaker doesn’t retail at $20K plus.

I have really dug my Def2s over the 5 years I've owned them, even more so with the SpatialComputer Black Hole sorting out bass integration issues in my room.
My main issue with them has always been the tweeter, which I feel has restricted the spkrs' microdynamic capabilities wrt to it's amazing macrodynamic prowess, leading to a dark tonal balance only lightened by bursts of treble when in the recorded material.
So, I'm so pleased that 213Cobra and Musicxyz have confirmed that treble extension is up there with the best, and not at the expense of the FRD magic macrodynamic picture, and opening up the microdynamic universe in music played.
Btw, to Musicxyz, do you think you're finally off your spkr merry-go-round and will stick with the Def4s? Can you resist the Dominances ( 3 FRD's, 2 supertweeters, 15" sub bass)?

Definition 1.5 was a livelier speaker than Def2, and its tonal center of gravity was shifted toward the upper midrange compared to Def2. The downside of Def1.5 was the MDF structure and the "cabinet talk" resulting from it at high SPLs. With Def2, Zu dramatically reduced the cabinet talk of the Definition architecture, giving it even more useful dynamic range, but one of the costs of tuning out the glare in Def1.5 was the slightly overdamped sound of Def2 (only in comparison to the incredibly jumpy Def1.5). The supertweeter network was improved as well, to tune out some of the older speaker's false sparkle evident in the supertweeter's anomalies. Def2 went as high, but it just didn't have all the tickle that Def1.5 had, along with that speaker's very top end distortions.

Def4 resolves the difference completely. Def3 should mostly. All of the liveliness of Def1.5 is restored in Def4, and then some. And all of the discipline and accuracy of Def2 is retained, and then some. The speed and openness of the nano-FRDs coupled to the tonal illumination provided by the smoothly extended Radian supertweeter eliminates the dark-tilt evident in Def2.

Solid State amps on Def2 went a long way to lifting the trace darkness in its tone, as did objective tube amps with extended top ends and bursty dynamic traits, but now that character isn't just mitigated. It's gone from the Def4 design and should be very much reduced in Def3's Def2 roots as well, since the nano-drivers are significantly responsible for the change (not the Radian alone). Def2s upgraded with 2010 HO FRDs pretty much lost the Def2 dark tilt anyway, so consider the small Def2 "overcorrection" to be adjusted out regardless which upgrade path you take.

Phil

My only technical query re Def4s is that the sub bass is downward firing into the floor. I know this is an established practice since many dedicated subs work the same way, but it all seems counterintuitive. Can anyone put me right on the pros of such an arrangement?
Musicxyz, you are adamant that a quality cable choice must be made for good audio, and same make used thruout system, a statement I agree with.
The Def4s have internal Event wiring which with Neutrik Speak-On connectors form a continuous loom with the Event spkr cables.
Does this mean that you are going to switch to Event from your current choice, and by consequence wire your whole system with Event?
Marc

While I cannot comment on the practice of the sub bass downfiring into the floor, I think that there is an advantage of a single sub vs the rear-firing, split-tuned array in terms of articulation and cohesiveness. It also allows me to position the Def 4s close to the rear wall. Plus, Sean told me that this approach is a lot less time consuming and less costly to manufacture.

I agree with both Phil's and Musicxyz's comments that CDs just seem to sound better - more enjoyable, engaging, etc. Like Phil, I am listening to CDs that I have ignored for years. It is not just resolution, detail, and extension. . . it is that they just sound better.

Neither Phil nor Musicxyz commented on the other advantages of the Def 4s. . . the off-axis listening (it was not very good with the Def 1.5s, it was a little better with the Def 2s, it is a lot better with the Def 4s) and the way the sound seems to fill space (it is a big sound without being a loud sound).

I am curious whether Phil thinks that the Def 4s require as much power as the Def 2s to sound their best.