JansZen logo
  • JansZen Loudspeaker, Ltd.
  • 2328 Dorset Rd. , Columbus, OH 43221 USA
  • Official website
  • info@janszenloudspeaker.com
  • +1 614 448 1811
  • No fax number available


Equipment[add model]

JansZen manufactures or has manufactured the following equipment (click to expand models list):

Dynamic Speakers
Electrostatic Speakers

General information [contribute]

1956 issue of Popular Electronics: The Janszen speaker consists of a series of four flat panels, each about six inches square. The plastic diaphragm is stretched across the frame of each panel. On each side of the diaphragm, in each panel, is a network of parallel wires which forms the outer electrodes of the push-pull circuit. This unit is intented to cover the frequency range from 1000 cps and up. It is furnished with a high-pass filter for crossover, and a polarizing voltage supply. It is free-standing and self-contained.

Barry Wilkinson (April 25, 2000): Janszen was the designer of the KLH nine.

John Hamm (December 9, 2000): Janzsen made add-on tweeter panels that can be used with existing speaker.

James Wong (December 10, 2000): Janszen Laboratory, Inc. (1956) was the original manufacturer of the Janszen speakers. Old addresses of the Janszen company are:

7516 42nd Ave. North, Minneapolis, Minnesoto 55427, USA
37 Newton Road, Plainview NY 11803, USA
69 Harvey St., Cambridge, Mass, USA

Per Andreasen (December 12, 2000): I am the owner of a pair of these beasts (model unknown). They are hybrids, with a 10 inch bass in a 50ltrs. acoustic suspension kabinet, with two 12x12 cm electrostatic modules in monopol mode. The Janzsen are vintage 1975-80, made in the USA. The electrostatic modules were made by Janszen. These modules were also used by McIntosh, ESS, Infinity and others.

A couple of months ago, I finished rebuilding the electronics because when I got them the high voltage supply and the audiotransformer were gone up in smoke. They are now working perfect, and playing fantastic.

Joerg Baar (April 2, 2001): The brand EPI uses the well known Janszen ESL-Panels (three per unit) in their model EPI-Stat 450. They where built in the early 70s in the US and cost about $900 each.

Dave J (February 14, 2005): All Janszen designs were push-pull (double-ended). Push-pull has the inherent advantage of making the voltage vs. position relation quite linear over a high degree of the available travel by applying both attractive and repulsive force to the membrane in both directions of travel (both half cycles). It also allows the implementation of a constant Q (aka, constant charge) electrical model that suppresses HD that arises from imperfections in the dimensions of the radiator elements. Proprietary aspects to the materials and dimensions made it efficient, manufacturable, and further suppressed HD to the point of being negligible.

To aid in your identification of Janszen tweeter units, note that this tweeter is square, about 5.7" x 5.7" x 0.38", and has a radiating area that is about 4.4" x 4.4", with a grid supporting a series of wire-like members on each side. Some versions had a paper diffuser covering the radiating area. The KLH 9 and Acoustech X were full range ELS's with one tweeter in each unit. The rest were hybrids with different numbers of tweeters arranged in various interesting ways, but each tweeter is either the original A. A. Janszen design or a good replica.

There actually was a second tweeter design that barely made it into production, which was a small, round unit with an off-center, round radiating area. Eight of these went into each ERC-139, envisioned as a low priced ($139), omnidirectional hybrid by an early 1970's startup called Electrostatic Research Corp.. ERC went belly up early in a fairly common business scenario where its initial level of capitalization was insufficient to overcome its initial level of management expertise.

Janszen web site (July 10, 2005): JansZen Loudspeaker was founded in 2005 by Arthur A. Janszen's elder son David. After decades as an engineer in audio, ultrasound, instrumentation, manufacturing processes, and industrial computer peripherals, David decided in 2004 to integrate and put into practice the loudspeaker work he had been incubating through intermittent experimentation during this period.

This work is based on ideas inspired by his early immersion in his father's work, degrees in physics and engineering design, extensive R&D experience with electronics, acoustics, materials-and-methods, and love of flawless sound reproduction.

JansZen Loudspeaker is starting small, and we are not planning to diversify and grow to a large size. We will remain a dependable maker of a small number of the very best sound reproducers housed in the very finest cabinetry. We believe our superb systems will become popular enough to drive a bit of company expansion, but our uncompromising technology and the artisan quality of our cabinetry will remain consistent.

David Janszen (March 11, 2014): How do I update the logo, website, and email contact info for my company?


Janszen web site (July 2005): Arthur A. Janszen's Loudspeaker Developments

Between the late 1800's and the late 1940's, there were many attempts made at producing a practical electrostatic loudspeaker. These used various clever ways of trying to work around the shortcomings in the available materials, and showed varying degrees of grasp on the physics involved. The physics of exerting electrostatic force on a membrane is very simple, but the physics of harnessing this basic phenomenon to make a high fidelity transducer is not. Although many succeeded in making sound, the frequency range was limited, the volume level low, the distortion high, and in many cases, much ozone was generated.

Harvard Underwater Sound Laboratory. The final leg of the trail toward the first practical electrostatic loudspeaker began during the Second World War at Harvard's Underwater Sound Laboratory, where Arthur A. Janszen (a.k.a., A2) was a Research Associate in Physics working on defense technologies for the U.S. Office of Naval Research under the lab's Director, acoustics luminary Frederick V. Hunt. A. A. Janszen's main focus in the lab during the war was developing hydrophonic technology along with related signal processing and control systems for detecting and homing in on propeller sounds from enemy vessels. To get a feel for the extent of the challenge, imagine developing the first acoustically self-guided torpedoes, and making them reliable and fail-safe using vacuum tube circuitry and relay-based rudder controls under conditions that included dropping them into rough seas from spotter planes.

After the war ended, another Navy project surfaced. A. A. Janszen had developed an electrostatic transducer to use as a high quality reference sound source for testing the hyrophones for the underwater ordnance project. This was further developed with the goal of producing a clear-sounding, directive cockpit speaker for our pilots. The contract was fulfilled in 1950 with the issuance of a groundbreaking Technical Memorandum authored by A. A. Janszen. This publication covered methods of construction and sonic performance that were very distinct from what had been invented up until that time. The Navy declined to pursue the technology further, however. Starting at about this time, the lab's development activities began to be gradually curtailed, and its facilities served mainly educational purposes for the next couple of decades.

The Apartment with the World's First Practical Electrostatic Loudspeaker. With the Lab's electrostatic speaker work over, A. A. Janszen decided to continue it on his own time in a small lab he set up in his apartment, from love of audio and the complex and fascinating physics of electrostatic loudspeakers. His laboratory notebooks from these nights and weekends were filled with a long progression of the brainstorms, conjectures, proofs, experimental results and conclusions of a well organized mind completely engrossed in the science. Many hobbyists these days know that it's really quite an experience when a beautiful sound comes out of a loudspeaker they've built. But one can be sure that it's even better for the pioneer who invents a new loudspeaker technology, especially when it makes remarkably better sound than had come out of any previous loudspeaker.

Eventually, A. A. Janszen realized it was possible to make this technology practical for use in uniquely high fidelity home loudspeakers, and began developing a manufacturable embodiment. All this work eventually resulted in patented technology that is still referenced to this day. Since the foundations were laid while in University employ, Mr. Janszen consulted Harvard regarding its official interest in the technology. The university declared that they had no interest, and released him from the need to make a patent assignment, something that would probably seem surprising if it happened these days.

JansZen Laboratory. In 1954, when he felt confident that he could succeed in selling his loudspeakers, A. A. Janszen resigned his position at Harvard and founded Janszen Laboratory, Inc. in North Cambridge, MA. At the Sixth Annual Convention of the Audio Engineering Society in NYC in October 1954, he presented a well received paper, "An Electrostatic Loudspeaker Development", which later appeared in the April 1955 issue of the society's Journal.

A. A. Janszen then developed a series of products that are now legendary, the best known probably being the 130 tweeter array, which made a great team with the best woofer of its day, the one found in the Acoustic Research AR-1. The model number corresponds with the radiating area in square inches, counting both sides. In 1959, A. A. Janszen decided to accept a license offer from Neshaminy Electronic Corp. (Frank Wetherill), and sold them rights to manufacture and use the tweeter along with help in developing products that incorporated it.

A. A. Janszen had also been developing the World's first full-range electrostatic loudspeaker, with ground-breaking industrial design by Boston architect William I. Barton. Models were put into field tests starting in 1957, and the design was refined. These prototypes received a very positive reception, and JansZen Labs began shipping a production version in early 1959. This development had attracted the attention of KLH.

During 1959, JansZen Laboratory's assets were transferred to KLH. A. A. Janszen was made a Vice President, and the KLH Nine was born. In their brochures, regarding the Nine's development and production, KLH described how it had broken with its usual cost model, sparing no expense to make what was simply the most accurate sound reproducer up until that time, and production was indeed exceptionally labor intensive.

A set of production radiators was built into the door to the lab at KLH, and visitors who went looking for the sound source sometimes had to be shown not only where the speaker was, but in some cases that there was a speaker, and not live musicians hidden somewhere.

A. A. Janszen was also involved in other projects at KLH, very notably the driver, equalization network, and industrial design for the KLH Model Eight, the first high fidelity FM table radio ever made. It's design and equalization philosophy are still found in the Tivoli Henry Kloss Model One.

After leaving KLH, some time then passed during which A. A. Janszen became involved in various non-acoustical activities, including agricultural practices development for Mexico through a joint effort between our State Dept's Agency for International Development and Mexico's State Dept. Eventually, he was ready for something new in the audio area again, although he kept up his A.I.D. work for another decade or so.

Acoustech. An investment group including Koss Electronics, Inc. approached Mr. Janszen with an irresistible offer to become involved in another full range electrostatic loudspeaker project, this one involving integration with the first solid state high fidelity amplifier of its type. This would become the Acoustech X from Acoustic Technology Laboratory, Inc. (a.k.a., Acoustech Labs, a.k.a. the Acoustech Division of Koss).

This system was known as the "Ten", in loose succession to the KLH Nine. Its model designation used a Roman numeral X to avoid confusion with the KLH Ten, an electrodynamic loudspeaker from KLH. Its updated, clean industrial design was again done by Mr. Barton. Its somewhat larger area gave it better bass extension. It was integrated with what was presumably the first class AB solid state hi-fi amplifer available, providing a very low distortion, maintenance-free system. The Acoustech X remains the standard by which many have judged everything that has come since.

ERC. In the mid-1970's, A. A. Janszen was retained by Electrostatic Research Corporation to develop a mass-market hybrid. What he produced was a fascinating and unprecendented, low-cost, omnidirectional design that would be called the ER-139. It employed a rear-radiating electrodynamic woofer/midrange designed by Charles McShane, former Director of Loudspeaker R/D at AR, and electrostatic tweeters with numerous innovations developed by Arthur A. Janszen. The purpose of omnidirectionality was to achieve a room-averaging effect similar to that of a full range electrostatic dipole, but without the unwanted front/rear phase cancellation. Some readers may recall that the "ball of sound" approach was moderately in vogue at the time.

In the ER-139 architecture, the ED speaker was mounted on the top and outside of a sealed enclosure, with its front firing downward into the enclosure, and its back left open. An inverted cone diffuser was mounted on its magnet assembly, and the sound from the driver's back fired upward against the diffuser's conical surface to achieve bass and midrange omnidirectionality. Arranged around the periphery above the diffuser were nine small, circular, wide dispersion, electrostatic tweeters that A. A. developed for the application. An open-cell foam grille surrounded the entire assembly.

The performance was exceptional for the price, which was only $139, and would have brought something approaching high-end sound to practically anyone who was interested. Although the company started up with a well reasoned mass-market ambition and developed a great product, it unfortunately did not have the means to pursue its plan to fruition.

After Neshaminy stopped manufacturing in the late 1960's, they were succeeded by Electronics Industries (Dr. Roger West), which continued to manufacture high quality loudspeakers under the Janszen name. Eventually the Janszen gestalt became diluted, however, by enthusasts who one must assume could not resist trying to improve on something already fully developed. The name was also used by third parties beyond Arthur's passing in 1991. The products were all based on versions of the 1950's JansZen tweeters, and were either tweeter-only units or hybrids. The tweeter elements were also sold outside to other companies. Information about most of the related systems is available in the models pages which you'll find on the right side of this page.

Many of the JansZen speakers made by JansZen Laboratory, Neshaminy Electronic, and Electronics Industries are still in service. Unfortunately, there were some owners of products made after that who experienced reliability problems due to exceptions in tweeter manufacturing materials and methods, with lifetimes of as little as three years reported in some cases. There were also some liberties taken with the choices of woofers and crossovers. We are sorry we could not be more effective at monitoring Q/A at these companies.

Owners of systems from JansZen Loudspeaker, Ltd. can rest assured that these products were designed and manufactured by a company founded and run personally by a deeply involved and notoriously picky family member who cares about every detail, David A. Janszen. These loudspeakers, like the genuine JansZen products of the past, are superbly engineered, and built using components that are exceptionally durable and stable, with enhancements even beyond what made the earlier systems so reliable.

In Memorium. For those who do not know, Arthur passed away in October of 1991, long before having a chance to see this phase of his audio legacy come to light. He is fondly remembered by those lucky enough to have enjoyed his kindness, originality, and wit, or had benefit of his insight and capabilities.

Refurbishing & modifications[contribute]

Janszen advert

David Janszen (January 2009): Our shop is available for repairing and refurbishing vintage JansZen speakers, and also the KLH Nine. We are not offering parts at this time.

Please visit the Janszen site and contact us with a description of the problem. Photos are helpful. Often, we can supply a provisional price quotation, although diagnostics attempted by telephone or email tend to be inaccurate.

Tom Dekoster (November 2002): Don Kliewer owns the rights to Janszen and lives in Wisconsin USA. He can provide parts, repair and any questions you have on Janszen electrostatics. You can contact Don Kliewer at 608 - 325-5111

Note from the webmaster: Don Kliewer passed away January 2003.

Brian Levy (December 2000): Several persons want sources for Janszen parts. During the patent suit, I located Don Kliewer, formerly of Janszen, who was still repairing and restoring the speakers.

Winslow Industries, Inc.
1005 30th Street P.O. Bx. 595 Monroe WI 53566, USA
+1 608-325-5111
+1 608-325-5113

He rebuilt my Z-412-HP crossovers and provided me with the original spec. woofers. It has been several years since I spoke with him so I can not warrant that he is still with the company or is repairing the Janszen.

The ESL driver developed by Janszen possibly is the standard design for most units even today. In addition to the ESL driver, it is interesting that research related to a patent infringement suit in Japan, the Janszen Z-812-HP and Z-824 may have been the first production speakers to utilize a true (not 3 post arrangement) bi-amp cross-over. It was determined that the crossover predated the Japan patent by more than a year and no English or other American production unit predated it from the research.

Henry Alterman (July 2001): Attention Janszen fans. I was a Janszen dealer from 1972 till its demise. I just found this site. I have schematics and access to part. we can help fix speakers cheap. Listen to Super Audio CD with janszen...its like the real music. You can contact us at: hjaiguana@aol.com

Joerg Baar (Januari 2001): Maybe this is useful for some Janszen-speaker owners. I picked up a pair of Janszen`s Z-210B in an eBay online-auction this summer for about 300,-DM. It is a hybrid-electrostatic with a 26cm Bass and two ESL-tweeters each. It is 8 Ohms and there is a potentiometer to arrange the treble level by changing the high-voltage bias of the ESLs. They came with no front-grille and one powersupply was defective. I fixed the power supply (replaced diodes) and decided to rebuild the grilles for the bass-speakers by my own.

The sound of the Janszens is stunning, the ESL's are in a great condition and work really fine. There was a slight hum hearable when I first hooked them up to the amp. I found out, that the mains transformer induces that hum into the bass-coils of the crossover network. Maybe other owners have the same problem. The solution is to rotate the mains transformer by 90 degrees so that the magnetic field is turned, too. I got the schematics for the speakers from a friend, it is not really the original one (it is from some other model) but the powersupply is almost identical. Joerg Baar Berlin/Germany

I also found a nice picture of a Z-500 at eBay. It must be a real old Janszen speaker where the ESL-panel is constructed as the driver of a wooden horn. It is funny, isn`t it. Never saw that model before. The owner did not write much about it.

Forum topics on JansZen

The following topics regarding JansZen in general can be found in the forums. Topics about specific models can be found on the model pages. If you want to start a new topic, click here.