JansZen Returns

When audiophiles speak of the pioneers who laid the foundation for their hobby, certain names are spoken with particular reverence: Kellogg, Rice, Klipsch, Voigt, Walker, and Janszen all indisputably make the all-star team. Arthur A. Janszen, like John Hilliard at Altec Lansing, worked on US Navy projects during WWII, but after the war focused on developing an electrostatic speaker for cockpit use in Naval aircraft. The resulting Office of Naval Research Technical Memorandum was groundbreaking in its description of construction techniques and sonic performance, but the Navy declined to develop the project further and, in fact, phased out the developmental aspect of the department.

Janszen decided to continue his research at home, however, and in 1954, founded Janszen Laboratory, Inc., in addition to delivering an epochal technical paper to the Sixth Annual Convention of the Audio Engineering Society in New York, "An Electrostatic Loudspeaker Development." There followed a series of major audio products: the JansZen 1-30 tweeter array (best known for its pairing with the Acoustic Research AR-1), the full-range electrostatic KLH Nine, the Acoustech X (that's a Roman numeral ten, not an "X," a distinction designed to keep it from being confused with the immense electrodynamic KLH Ten), and the Electrostatic Research Corporation's ERC-139, a small-scale hybrid speaker that was probably a bit too much ahead of its time. Janszen also developed the driver, EQ network, and industrial design for the KLH Model Eight table radio, the linear ancestor of the Tivoli Henry Kloss Model One so popular today.

Arthur Janszen died in 1991. However, there is a new JansZen loudspeaker, the JansZen One—developed by a new Janszen, David, son of Arthur.

David Janszen tells us that the $18,000/pair (introductory price) JansZen One is a fully powered, two-cabinet electrostatic/electrodynamic hybrid that boasts wide dynamic range; cylindrical, forward-only radiation pattern; and negligible levels of harmonic and intermodulation distortion.

We reached DJ in Columbus, OH recently and chatted with him about his new company and his new speaker.

Tell us why you decided to develop the One.
"I've been into audio design for a very long time—it's in the family, in the blood. As the oldest, my dad took me under his wing from an early age and hauled me into the various places where he was working and showed me everything. I can remember being very impressed at the existence of a 22 mega-ohm resistor when I was about nine. Like wow—this will make my relaxation oscillator go so slooow! My dad would let me wander around the KLH factory floor, and I'd bring a fistful of parts over to the guy in the parts cage and ask if they'd let me have them and the answer was always 'yes.'

"So, not that long ago, I decided it was really about time to do something with all the audio ideas I had on how to improve the old JansZen loudspeakers—and I'm not just talking about the techniques for manufacturing the radiators, but the morphology of the whole thing, so it wound up overcoming some of the drawbacks I've always experienced."

What drawbacks were those?
"I've always had a pair of KLH Nines or Acoustech Xs around (I currently have a pair of Xs in the living room). I love 'em, but they only sound really good if you're in the spot where the two tweeters are both aimed. They have those 4" tweeters, and I don't know if you're familiar with the equations for it, but at 4", you have beaming all the way down to 2kHz, so that makes it tough.

"I've changed that so the tweeters are in a line array, so they create a cylindrical soundfield and the dispersion therefore is very wide. By making the whole thing very tall, you can get all the response just about anywhere you'd want to be, as long as they're aimed straight forward—and as long as you're less than 7' tall and more than 2' tall.

"I had to design my own electrostatic drivers for these speakers. I have a big box full o' prototypes. All of them worked, but most of them didn't work as completely as I hoped. I made a lot of 4" by 6" elements employing different stator materials and configurations. I finally had enough data to decide what to do, and I built a final—more or less final—embodiment and realized that the materials I was using weren't very flat, so it took me a few tries. Eventually, I wound up with enough successes to build an entire unit and boy! it was exciting when I heard that thing.

"The electrostatic elements are arrayed in vertical bays—there's one narrow bay that's a tweeter and two wider bays that are the midrange/upper woofer elements. Those are all next to one another, and there are three of them on top of one another to make up the electrostatic part of the speaker.

"One side of the upper part of the cabinet that contains the tweeter/midrange arrays is tapered. The elements are rectangular, but the cabinet is asymmetrical to distribute the edge diffraction peaks. Take the elements right to the edge and you get one huge diffraction peak, so I go for a bunch of little peaks that all overlap and you can’t hear or measure 'em."

What about the woofer section?
"Thilo Stompler at TC Sounds makes absolutely fabulous woofers, so I sourced the bass driver there. I was intent on using a 12" woofer, so I could get that U-R-there feeling, the sensation of impact against your body. Because I've gotten the distortion so low on the Model Ones, they don't sound that loud—but they really are loud. That translates to sensation.

"I'm prejudiced against class-A amplifiers and small woofers, so you don't want to get me started on that!"

Oh, do go on.
"Well, class-A amplifiers are a thing of the distant past. I guess that, after figuring out negative feedback, one of the first things engineers discovered was how to get away from triodes and class-A operation to get distortion down and linearity up. Add more grids, get some feedback in from the grids—eventually, there were pentodes and you could get a very nice A/B output stage that would have very low distortion. Some of the best executed were Marantz's EL34 circuits.

"Some people think there's something more pure about a class-A amplifier, but in my view, all they do is introduce distortion that makes an adequate woofer sound fatter. Some people think they sound sweeter, but it's quite the antithesis of what I'm trying to do. If you do it right, an electrodynamic woofer can have very low distortion. If you use amplifiers that also exhibit very low distortion and transformers that are carefully designed to have low distortion (of course, you need a step-up transformer for the electrostats), the overall effect is a natural sound.

"I've gone to class-D for the electrostats. Class-D does typically have a strange type of distortion that sounds unpleasant, but I've found a topology that generates the ramps so that there's extremely low distortion—below 0.1% all the way up to full amplitude. Class-D doesn't generate much heat, so I can seal it up in the box without ventilation and not have to worry about it.

"With class-D, there just aren't good enough FETs available to get a lot of power, and electrostats are very efficient, so that works well. For a woofer, you need a lot of power, especially if you're using a cabinet that doesn't take up the entire room, so I'm using the kilowatt (1000W) amplifier, which is technically a class-G topology—essentially a class-A/B, but the power rails can be stepped depending on the power requirements of the moment. Because of that, it is also very efficient, so it, too, can be sealed up in a box.

"The woofer element is in what I guess could be described as 'an undersized transmission line termination.' It doesn't make the cabinet seem like a completely infinite baffle, but completely sealing the 1.5 cubic-foot box pushed the resonant frequency too high, so I vent the lower cabinet into a 'chimney' in the rear of the upper cabinet. At the very top is a slot that vents the chimney. I guess you could say this design has elements of three different enclosures—it's not a sealed box, it's not a complete transmission line, and that vent would certainly be undersized in a regular vented enclosure. I think it works out pretty well."

How do the two cabinets connect?
"The upper part connects to the lower assembly with four of those quarter-turn furniture fasteners, and the connections are made when you set the top down on the bottom. You can't do it wrong. I've been an engineer all my life and I'm really into making things difficult to break—not least because I've usually had a boss who was an expert at breaking stuff!"

A high-tech loudspeaker that's reliable—that is an audiophile dream come true.

The JansZen One loudspeaker should be available as a finished product by June, and JansZen is offering the first 25 pairs at an introductory price of $18,000/pair. After the initial run, the price will be $26,000. Order details are available at JansZen's website. Demonstrations will be available in the central Ohio area.

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