Company origins

Arthur A. Janszen, 1962

Arthur A. Janszen's Loudspeaker Developments

Arthur Janszen founded the JansZen brand in 1955. He was an example of what was then known as an applied physicist, someone who later would be called an engineer. He invented many things in his life, but is known in audio for inventing the first practical electrostatic hi-fi speaker, a wide-range tweeter that covered midrange through ultrasonic frequencies (800 Hz - 30 kHz).

In the mid-1950's, he was awarded a patent on his panel and launched Janszen Laboratory Inc.. There he quickly developed and marketed two add-on tweeter speakers, one with an array of two and the other with four of his panels. These were initially paired with the AR-1 acoustic suspension woofer invented by Edgar Villchur at Acoustic Research Corp.. Together, they helped usher in the high fidelity era.

The basic physics of exerting electrostatic force on a membrane is very simple. On the other hand, the engineering required to harness this basic phenomenon for creating a durable, high fidelity transducer is not.

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 some showed a considerable grasp of the applicable principles.

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 high fidelity electrostatic loudspeaker began during the Second World War at Harvard University's Underwater Sound Laboratory, where Arthur A. Janszen needed a sound source for testing hydrophones with far better frequency and transient response than the available transducers.

At the time, A. A. Janszen was a Research Associate Professor in Physics working on defense technologies for the U.S. Office of Naval Research under the lab's Director, acoustics luminary Frederick V. (Ted) Hunt.

A. A. Janszen's main focus in the lab during the war was developing hydrophone technology along with related signal processing and control systems for detecting and homing in on propeller sounds from enemy vessels. Specifically, these weapons were to be used against Nazi submarines that had been attacking Allied military and civilian ships. The Nazi's developed an acoustical torpedo of their own, but it had two main problems: It could not tell propeller noise from other noise, so it was easily fooled by dragging a noisemaker behind a ship, and on at least two occasions, one turned around and sank the U-Boat that launched it.

To get a feel for the extent of the Harvard team's challenge, imagine developing an acoustically self-guided torpedo, essentially an autonomous underwater vehicle, and making it reliable and fail-safe using vacuum tube circuitry and relay-based rudder controls under conditions that included dropping them into ofttimes rough seas from airplanes in the presence of ambient noise interference.

Medal awarded to AAJ upon completion of the torpedo project

After the war ended, another Navy project surfaced: A new use for the electrostatic transducer that A. A. Janszen had initially developed as a high quality reference sound source for testing the hydrophones 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 that were distinct from what had been invented up until that time, with sonic performance that was far superior. The Navy declined to pursue the technology further, however. Starting at about this time, the lab's development activities were gradually curtailed, and its facilities served mainly educational purposes for about the next two decades.

The Apartment with the World's First Practical Electrostatic Hi-Fi 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, patented the basics, and began developing a manufacturable embodiment. All this work eventually resulted in further 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 today.

Arthur A. Janszen, 1962 JansZen Laboratory, Inc. 

In 1954, when he felt confident that he could succeed in selling his loudspeakers, A. A. Janszen resigned his position at Harvard and in 1955 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.

The original JansZen tweeter

A. A. Janszen then developed a series of products that are now legendary, the best known probably being the 1-30 tweeter array, which was typically teamed with the best woofer of its day, the one found in the Acoustic Research AR-1. The 1-30 model number corresponds with the 130 square inch radiating area for the array, counting both sides. In 1959, A. A. Janszen decided to accept a license offer from Neshaminy Electronic Corp. (Frank Wetherill), which had been handling the manufacturing for a few years, and sold them rights to manufacture and use the tweeter in their own designs, along with help in developing those designs.


JansZen 1-30 4-panel arrays atop AR-1w's, first offered in 1956 -- the first high end audio speaker,  and which set a high fidelity standard for at least 15 years

A. A. Janszen had also been developing the World's first full-range electrostatic loudspeaker, with ground-breaking industrial design by Boston architect William [Bill] I. Barton. The two had met at Harvard and got on very well, becoming close friends for life. 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.

Triple pair of KLH Nines (courtesy of P. Chance)


During 1959, JansZen Laboratory's assets were transferred to KLH (KLH Research Corp.). 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. Disassembly of these speakers reveals a number of interesting fabrication and assembly aspects. 

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 where the speaker was, and in some cases were surprised to find that the sound coming from a speaker, and not live musicians hidden somewhere.

KLH Nine, Triple-panel stereo dream system, 1961

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

KLH Eight

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.


An investment group headed by Koss Electronics, Inc. approached A. A. 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, Inc., a.k.a. the Acoustech Division of Koss Electronics).

Acoustech X (Ten)

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 created by Mr. Barton. Its somewhat larger area and greater cabinet mass gave it deeper bass extension.

It was biamplified with what were presumably the first Class AB solid state hi-fi amplifers generally available, providing an integrated, very low distortion, maintenance-free system. Anyone who still has these today would probably want to replace the amplifiers with modern equivalents, or rewire them for use with external amplifiers, but their electrostatic panels set a new standard. (Our shop is available for the external amplifier conversion.)


In the mid-1970's, A. A. Janszen was retained by Electrostatic Research Corporation to develop a mass-market hybrid. What he developed was a fascinating and unprecedented, omnidirectional design that would be called the ER-139, to be retailed at only $139/pair.

It employed a rear-radiating electrodynamic woofer/midrange designed by Charles McShane, former Director of Loudspeaker R/D at AR (Acoustic Research Corp.), 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.

ER-139, without grille

In the ER-139 architecture was unusual. A rear-firing cone midrange/woofer was mounted upside-down on top of a sealed enclosure, with the rear of the woofer firing upward. An inverted cone diffuser was mounted on its magnet assembly, and the sound from the driver's back was deflected by the diffuser's conical surface to achieve midrange omnidirectionality. Arranged around the periphery above the diffuser were eight small, circular, wide dispersion, electrostatic tweeters that A. A. developed for the application. Initially, an open-cell foam grille surrounded the entire assembly.

The performance was exceptional for the price, and would have brought high-end sound to practically anyone who was interested. Those accustomed to the popular, mid-priced speakers of the time were impressed. 

Although the company started up with a well reasoned mass-market ambition and developed a great product, it unfortunately was not run in a way that would take its plan to fruition. Once the tweeter and its manufacturing tooling was complete, the founder, Frank Denessen, used a large portion of the investors' capital to buy the building the company occupied, rather than use it for marketing and production. He then drove A. A. Janszen off by failing to honor his commitments and being generally troublesome. He then shook off his remaining commitments by folding ERC in a chapter 7 bankruptcy. This allowed him to keep the investors' money, keep the building, which was now debt free, dissolve the original and secondary debt on his personal house, and terminate A. A. Janszen's rights to the tweeter. He soon re-opened in the same building under a new name, Denessen Electrostatic, making more conventional designs created by his lead technician that ioncorporated the new Janszen tweeter. Some might best remember Denessen for the tone arm alignment device whose design he put his name on, but we remember him for being an enthusiastically friendly con man with a drinking problem and disppointing taste in music. 


After Frank Wetherill retired and Neshaminy ceased its operations in the mid-1970's, its assets were acquired by Electronics Industries (E.I.), a group that included Dr. Roger West, who went on to found SoundLab. E.I. continued to manufacture loudspeakers using the JansZen mark. The name's momentum was also utilized 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 tooling for molding the frames for these tweeters has passed through a number of hands over the years, and redesigns were done by some.

Information about most of the related systems is available at Many of the JansZen speakers made by JansZen Laboratory, Neshaminy Electronic, and Electronics Industries are still in service.

JansZen Electrostatic Z-412

Purchasers of new systems from JansZen Loudspeaker can rest assured that these products are 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 early systems so reliable.


Arthur passed away in October of 1991, long before having a chance to enjoy this latest work. He is fondly remembered by everyone lucky enough to have known him, who experienced his kindness, originality and wit, or had benefit of his insight and capabilities.

Arthur A. Janszen holding the first ERC-139 tweeter assembly, 1975