Zu Definition owners who stepped up to the Def 4

The 12" downfiring sub in Def4 is cleaner, quicker, and it loads the room more evenly. It is in all ways better than the 4x10" linear sub array on earlier Definitions. Plus the internal amp is better, cleaner, more powerful -- and you have far more control over deep bass/room interations with the parametric, phase and hinge frequency variables. The rest is in the Zu Definition 3 thread here.

Phil

Markpao,

All other things being equal, more cone area to move air is "better." But all other things aren't equal in this case. Four drivers don't deliver the same absolute dynamic unity as one. The 12" in the Def4 is a substantial cast-basket driver with a more powerful motor and it is bolted horizontally to the massive machined aluminum plinth rather than screwed on the vertical plane to wood. And even if that weren't enough difference, Def4 adds an array of five controls for the sub, against just a level control in Def2. The one area of theoretical compromise is that the sub's internal amp is proximate to the 12" driver. If you really worried about that the amplification could be externalized, but then the elegant unitary integration of all Def4 elements into one simple box would be ruined. Anyone so inclined can always save their money for Dominance if they hanker for more boxes and cable on the floor!

Phil

There's certainly room for an internal amp in Dominance. In designing a SotA speaker, Zu just took the absolutist route to require external amplification & control for the 15". As a Zu customer I've expressed my preference for a version of Dominance with the Def-like integrated amp/control module internally mounted. It remains to be seen whether the market gets it. I'm sure it's not Sean's highest priority nor should it be.

Phil

When I mentioned the compromise of an internal amp, I was referring to the known degradation of the sound of especially solid state circuits subjected to vibration. But the deleterious effects are mostly noticed in upper midrange and high freuqnecies, if they are noticed at all. I don't consider it a significant issue in the Zu sub imprementation. Offering a kit permitting removal of the internal amp and controls in exchange for easy connection of external sub amplification and a croosover or active low pass filter is essentially a way to revive the concept of the Definition 1.5-era Definition Pro, which had few takers. But in this case it can be done without having to ship a separate model.

At the time of the Def Pro, Definition 1.5 had only recently gotten a sub level control. (My original Def 1.5s in 2005 were delivered with no sub adjustment of any kind. My first feedback to Sean and Adam was to ask for a level control and suggested that all Definitions should be so built. Sean and Adam soon showed up at my house in Los Angeles to do a field upgrade and then they proceeded to visit every Definitions owner in the US to install level controls.)

So Def Pro was introduced in the context of Definitions only having simple level controls on the sub array. I think with the five-way sub control panel on Def 4 along with the big driver upgrade, downfiring, and the amp improvement inside, the difference externalizing the sub electronics will be so much smaller that it will be worth tangling up your room with more gear and cable in only the most demanding and extraordinary circumstances, like if you are trying to load a very large space and plan to use high power monoblocks on the main drivers/supertweet and need something mammoth for the sub. And if you were going to that trouble, a pair of Zu's new subs used in conjunction with the internal Def4 sub would be cleaner and likely more effective.

But it's the Zu way to accommodate downstream customization so takers there may be. Still, one of the chief appeals and value propositions of the Definition format is having everything for 16Hz - 25kHz objective presentation in a single simple column for regular 2.0 gear.

Phil

It's not strictly D'App spacing. Regardless, combing in Defs is incidental and isn't worth worrying about.

Phil