Zu on Zu

I’ve just read through the bottom third of a very, very long and passionate thread here regarding Zu speakers, generally centered around whether or not our designs employ crossover networks or not. After doing this, and with a great deal of restraint not to write you all off or retort “screw ‘em all” (Yes, I try and keep a clean mouth, had the other word there for a bit but on reread... But honestly, I might have to use such words to keep the attention here.)

I feel a nice long ramble coming on but before I open it up full throttle all cross-country like letting it all ride, let me make a few brief points. I also know that in order to accurately communicate we must use technical jargon and it is also evident that the majority I will be communicating with are concept-oriented and likely do not have a fundamental background in loudspeaker design or physics. Very likely you are getting your info from that STD cookbook—how to build iffy loudspeaker by VD. Big mistake if you ask Gene Czerwinski, Lars Nordland, and others that have made loudspeakers their life's work. If you haven’t at least studied Harry F Olson (Hey Lars, Harry was a Swede too, born in the US though, didn’t have your cool accent) and you are posting your opinion as acoustic-physics-based you should stop, do more home work and come back ready to play ball. So, this will be wordy, technical, maybe even problem/proof centric, we’ll see. Yes, this is a pain in my butt, it is a big distraction, the few hours that are going to go into this are stolen from my family and I’m pissed about it. If this were during the work day I would still be pissed because I got better things to do, this is not a real contribution to the art of audio, my contribution should be realized in product and systems, not Q&A. But there is a need and if I let the anti-zu thing go too far it will most certainly hurt revenue and thus the mechanism through which Zu’s ideas are realized. It is also difficult as I do not think in a linear fashion. Ideas are expressed in my mind as if they were on a stage, roughed in concepts seem to just take shape, the various parts interplaying and emerging simultaneously, and I am able to see the problems in my head, work them out virtually. I suck at math generally to say nothing of my English and spelling skills. Going from thought to pounding on this keyboard is like flying along at 170 MPH and then having to slow down for a school zone. I also drop words, sometime complete ideas, hands are always behind. So, read with care, realize this is not what I like doing and feel free to NOT expect more of this blather here. We will however address the wives' tales, misunderstandings and music over at ZuAudio.com. We hope to give the Zu guys some proof support and also hopefully convince some of you ATC and Klipsch onwers to give us a try -- okay, at least respect what we have created. By the way, you ATC guys, I have my one secrete sauce and rebuild tweaks for their very cool 3” dome. It’s three hours per driver, shop rate is $60 / hour. Satisfaction guaranteed. On second thought, I’ll be asked a bunch of questions, let’s come back to this if Zu really is just a fad. I do think that is one of the top 50 drivers of all time. Love the thing.

Cynicism is a good thing. I don’t care if you don’t like the Zu sound, I don’t care if you think you can do it better, I don’t care if you only like to listen to unamplified triangle made from C76200 alloy played only at night 100 miles from the closest paved road—I don’t care. But when you armchair engineer my stuff and rag on my customers, and do it with this “I don’t mean to offend” attitude but you really do—ya, this gets to me, at least it did tonight.

There are a ton of things I think Zu should now begin to talk about. Finding the time for such writings will be difficult but we are committed to it. For now I can only briefly address the whole crossover thing. I will come back to it and give it a proper writing with Adam to run proofs and math and to pick up what I let drop. I swear we will do it in the very near future.

Enough all ready. Zu Tone, Druid and Definition loudspeakers do not use a crossover network.

“Crossover”, like “speaker” is short for loudspeaker, is short for “crossover network” as applied to audio. Webster’s New Universal Unabridged Dictionary copyright 1996 defines a crossover for audio networks as: An audio circuit device that sorts the impulses received and channels them into high or low-frequency loudspeakers. This is a very non-technical definition but gets the point across. Our full range driver is directly connected to the binding posts with nothing more than cable, designed to reduce reactive loads, from voicecoil to input terminals. There are no devices of any kind between. Simple right? No, many think that the dynamic behavior of the drive unit must be factored in. I agree, the engineer must consider this but it is not part of a defined crossover though must influence a builders selection and execution if a crossover network will be used. Since our driver is an electrodynamic coil-in-static-flux type it has reactive components. These can not be eliminated. We tried many new types of coil windings on our motor, trying to first reduce the inductive rise without sacrificing dynamic range while also looking at how to increase electromagnetic densities. After a lot, or is it alot, of this and that, success and flat out failures, we ended up with a basic down and back, windings on top of former voicecoil. This voicecoil is rather big for a drive unit with a bandwidth of 8.5 octaves in room response, 5/8ths of an inch long and 2 inches wide, immersed in a high density magnetic (B) field uniformly covering the complete coil, static B field density has a practical usable length of 1 inch allowing for linear full coil immersion operation of roughly 1/4”, 1/2” peak to peak. The drawing of the motor assembly resembles a neutral hung design. Consider now that we have a mechanical xmax on the suspension system, spider and surround with a gib factor of about 20 / 80, you can see that our drive unit is quite capable of very high SPL levels, very linear dynamic behavior, reduced inductive rise as the coil only sees a shunt or little static B field at full band power levels in the 100 Watts RMS area. Full bandwidth thermal dissipation capacity on our Zu260FR/G2 is 200 Watts, 400 Watts if used with an active high-pass set at 50 Hz (2nd order) for those of you who might find yourself using them for DJ monitoring. What, none of you are in to the DJ scene, man you really are missing out. A motor, which accounts for all the electromagnetic functions of a driver, must also be modeled with the transducer's intended impedance matching counter part, the thing that couples to the air and that things suspension, and visa versa.

I also noticed that somebody here is a big active crossover fan. Cool. This has real promise and is how everything in pro is done. While the digital technology has finally come around well enough to make decent sound I personally feel that for great texture and tone the main transducer should cover as wide a bandwidth as possible keeping that first crossover point below the modern third octave (64 Hz point give or take a bit). But this really is a completely differnet topic, we are talking about home audio applications, not OzFest stuff where active crossovers and crazy solutions are essential. For this club style party we played at HE2006, we ran our druids with the Crown I-Tech power amps. A two way system with a LR12dB/ at 52 on the Druids, BW6dB/ at 28Hz on our Druid riser subs. The room had a big fat boom in the thwack range. We really lit the system up for DJ Presto at about 2:30 AM, man was that cool, crystal clear, hard hitting sweet sound at concert levels that would make even Gordy Johnson cry!

Speaking of the show. I had this 20 minute talk with a Bose guy. I really wanted to say, but didn’t, hey, what cool stuff have you made anyway, spending ten times the Chinese made product costs on market, get the flip out of my room. Instead I had to listen to his absolute understanding of cone modes and break up. This is why you ain't gnu see anything cool from Bose anytime soom. This is a lead-in really. Here is an actual quote by an earlier blogger’s post: “I too am sure that nothing aphysical can be happening---if only because that would not be allowed by physical laws.” Really, somebody wrote that? Not sure if this was a Zuid or a Zu is a fad guy, either way we can’t think like this. If an anti, say something that sounds kinda good, use the word physics to back you up and move on. That’s a load of crap. First, we humans know little more than that friendly little black ant crawling under your door. Don’t they call ‘em piss ants or something. Really, you take any branch of physics, try and take it down to a fundamental level and see if the whole thing doesn’t fall apart. Yes, Newtonian physics let us get surprisingly close to the average model of many things, let’s us measure and repeat basic stuff. But the further we dig the more we realize we are nothing, understanding virtually nothing on a base level, only knowing how to repeat and model not truly getting the whys of it all. Physical laws are discovered, they do not allow or disallow, they behave in a particular way under particular conditions, understanding being based on the particular way you measured and model the thing. Again, you break stuff down far enough and new models and behavior emerge. The physics student that does not subscribe to absolute will be find himself in a position for discovery and contribution with greater frequency and magnitude. Me, I’m only a physics major drop out, largely self taught in acoustics starting with passion at the age of thirteen. Favorite reading back then was Olson. If a Zu guy said this now you know why I started jumping up and down when I read it.

Physics, it’s super cool. It’s our chosen discipline here at Zu. We hope to add to the knowledge base, not simply follow everyone else’s models. And when it comes to loudspeaker and cable design we want to lead, we intrinsically question others models and proofs, preferring to go it on our own, discovery is still a much bigger fixx than recreation.

Give us a break, we are a bunch of guys that love music and sound just like the rest that post here, bootstrapping our ideas to life. We are just asking for a bit of time to mature, get our communications together, figure out marketing a bit, find ways to get the product in your home for a listen. If you don’t like it, no big deal. But if you are pissed off cause you think you should be where I am, then get busy man. Make it happen.

Look for more at ZuAudio.com in a few weeks. Really, we are committed to the communication of technical assays, if for no other reason than to save our supporters from going crazy here at Audiogon.

I’m tired, need to see my wife, get some lovin, eat breakfast with the kids -- at home and not at Zu.

Later,

Sean