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Janszen Loudspeaker Model One Floorstanding Speaker Review

Ed Momkus reflects on the validity of electrostatic speakers

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Janszen Mode lOne SpeakerExcept for the Klipsch horn-based speakers I owned between 1977 and 1981, I have been the owner of electrodynamic point source speakers all my life. In 2002, I seriously considered the Martin Logan Prodigy, but elected instead to purchase Bower & Wilkins 802. That’s the closest I ever came to buying a pair of electrostatics. The 802s eventually were replaced by the 800D, and the thought of ever deviating from dynamic drivers was banished from my mind…until I had the chance to review the Janszen Loudspeaker Model One.

ESLs in General

Audible advantages of electrostatic loudspeakers (ESLs) include exemplary frequency response and a musical transparency that can far surpass that of electrodynamic speakers as a result of the low mass of an ESL’s radiating surface. Transients can be lightning-quick and soundstaging expansive, with musical nuances easily discernible. There are design advantages galore – ESLs can be designed without the usual crossover filters and enclosures that can color or distort the sound of electrodynamic speakers.

ESLs also have their disadvantages. Most are designed without an enclosure and act as a vertical dipole line source. Such a speaker often requires special care in placement, although, as we shall see, once you find the right spot, an ESL can have fewer room interactions. Some also cite the directionality of ESLs as a disadvantage. In many ESLs, the sweet spot can be relatively small, though I’ve heard plenty of point source speakers whose sweet spot wasn’t that great. There can also be difficulties when ESLs are exposed to a high humidity environment. However, a greater disadvantage, in my opinion, is a lack of bass response. This is due to cancellation of low frequencies in dipole speakers and the difficulty of reproducing low frequencies with a thin vibrating membrane with little available excursion amplitude.

Solutions for lack of bass have included the use of extremely large panel areas, electrostatic subwoofer panels and double membrane panels that allow large diaphragm excursions. Some manufacturers step up the bass with a higher transformation ratio than the mid and treble. However, a more popular solution has been the use of a hybrid design using a dynamic speaker, usually a subwoofer, to handle lower frequencies. Theoretically, conventional cone woofers can be arranged to produce radiation patterns similar to ESL membranes. However, there are problems in integrating such a woofer with the electrostatic panels, since their operation is fundamentally different. Most ESLs are line sources whose SPL decreases by 3 dB for each doubling of distance, while a point source’s SPL drops by 6 dB for each doubling of distance.

In a brief (and unverified) bout of research I determined that Martin-Logan, Metrum Acoustics, Innersound, and its successor the Sanders Sound Systems, build hybrid designs with conventional subwoofers. Final Sound builds stand-alone electrostatic panels with freestanding bass-modules as an option. Audiostatic and Sound Lab exclusively build full-range electrostatic panels. Quad, maker of some of the earliest full-range electrostatics (and among the most respected), makes a range of electrodynamic speakers, but its top models are pure electrostatic. King Sound makes mostly full-range ESLs, but also has a system which incorporates a free-standing bass module. The Janszen Model One is a hybrid design.

Like Father, Like Son

It is impossible to put a life as rich as Arthur Janszen’s into a single paragraph, but I’d like to give you a flavor of it anyway. Arthur Janszen was a Senior Research Assistant Professor in the Acoustics Research Laboratory at Harvard in 1946. He received a patent for the first practical electrostatic loudspeaker in 1953. In 1954, Arthur’s Magnetic Amplifier Corp., of Waltham, Mass. became Janszen Laboratory, Inc., of Cambridge, Mass., with him as President. Production began in April, 1955 with the Janszen Model 130. In 1957, the first test models of a full-range ESL were put into field testing. In 1959, rights to the Janszen mark were purchased by Neshaminy Electronic, and Janszen Laboratory’s assets were transferred to KLH Research and Development Corporation. At KLH, Arthur served as a Vice President, and KLH soon undertook production of his full-range ESL, which was named the KLH Nine. Arthur died at the age of 84 in 1991, after a long and distinguished career. Between these milestone events Arthur Janszen remained influential in loudspeaker design and in several other areas related to applied physics. His work was significant in advancing ESL technology to where it is today.

The manufacturer of the Model One, Janszen Loudspeaker, Ltd., was founded in 2005 by David Arthur Janszen, Arthur’s elder son. Influenced by his father, he had been knowledgeable about with ESLs from childhood, and went on to begin a technical career of his own with degrees in physics and engineering design. He eventually decided that it was time to get serious about ESLs. The Model One is the present culmination of that effort.

The Model One

The Model One’s treble and midrange (and some upper bass) is provided by electrostatic drivers of David’s own design that cover the 200 Hz to 30 kHz range. Each speaker has three adjoining vertical electrostatic panels, with each panel having one tweeter element and 2 mid/woofer elements. The three panels act as one tweeter/mid and one midrange/upper bass line driver. The panels are slightly offset by design, a proprietary design of Janszen. The electrodynamic woofers are two 8″ cones that work in a sealed enclosure. One woofer is mounted at the top and one at the bottom. According to David, this arrangement improves matching to the ESL’s line radiation pattern and reduces room mode excitation. You should also note that the left and right speakers are not interchangeable, and the tweeters are situated inboard.

When he was setting up the speakers, David Janszen stressed that one of the key features of the panels is the achievement of adequate damping – something that he feels is lacking sufficient attention in other electrostatic designs that thereby exhibit colorations. As David says on the Janszen website: “As with a shock absorber, all motion is fully controlled, reacting precisely to the musical signal, never bouncing along on its own after a sound is supposed to end. This eliminates the resonant coloration affecting see-though ESL’s.” I’m no speaker designer, but this is straightforward enough to make sense to me. Every experience I’ve had with stability/vibration control has generated positive results.

David also mentioned that one challenge with electrostatics is that they need protection from over-voltage conditions to avoid destructive arcing. Since they sound the same at all levels, there is no audible warning when nearing the limit. Consequently, the Model One incorporates a circuit that pads the signal, reducing the voltage to the panels while keeping the load on the amplifier at no less than 3 ohms. There is an LED that goes from blue to green to yellow to let you know when the limit is being approached, and finally to bright red when the protection circuit is operating. The protection circuit was non-intrusive when it was simply monitoring the signal, and I could barely hear any difference in the sound even when the circuit was actually engaged (at which point it was REALLY LOUD!).

All this design stuff was quite interesting. However, the truly interesting part is that the Model One is a monopole – it’s enclosed in the rear and only fires forward. Transforming an ESL from a dipole to a monopole has several immediate effects, but from the user’s standpoint the most obvious is the ease of placement in the listening room. When David Janszen brought the speakers in to my room, we moved my B&Ws out of the way, and he placed the Model Ones just a bit further apart than my B&W’s placement. Voila! We were done, and glorious music was filing the room. In the past I have spent weeks seeking correct speaker placement, but the Model Ones were a snap. Minute adjustments could help a bit, but once you got them in the approximately optimal location you were golden. Room interactions were minimal, to the point that engaging my Lyngdorf digital room correction system helped, but nowhere near as much as with my 800Ds. Bass effects were minimal, which I attribute in part to the top/bottom dual woofer alignment, which has been very effective in the Deadalus Audio Ulysses.

Notwithstanding this ease of placement, there was one issue I encountered which took a little work. After some listening I realized that the image was pulled slightly to the left. I quickly found I could address this by toeing-in the speakers a bit more, but this measure also reduced the width of the sweet spot, so I opted to adjust speaker balance from my preamp. After further evaluation I came to the conclusion that the left-side shift was the result of the slightly asymmetrical shape of my room, which could be eliminated by greater toe-in. I don’t have this issue with my B&W 800D since I point those directly at the listening chair with maximum toe-in.

The speakers weigh 150 lbs each. I checked the Martin Logan and Soundlab sites and noted that the Model One is physically smaller and lighter than Martin Logan’s CLX and most of Soundlab’s models. Available as an option are powered, long throw woofers for bass extension to 20 Hz, and adaptation to room acoustics. Amplification for the option is via B&O ICEpower with toroidal transformer linear supply, paired with analog bass EQ for room compensation.

Let’s Talk About The Sound

The Sweet Spot. The “sweet spot” is quite wide, much to my great joy. I was worried that it would be as narrow as some other stats I’ve heard. They do have a restricted vertical dispersion, and are clearly intended to be listened to sitting down. However, this restricted dispersion likely helps to minimize floor and ceiling reflections, thus contributing to the clarity of the presentation. Imaging was actually quite good throughout the room, which David had mentioned at the time of installation. Even positions well to the left and the right sides of the speakers exhibited the spatial characteristics of a soundstage.

Transparency and Soundstaging. As mentioned above, these speakers are meant for seated listening. It is at this point that soundstage width, depth and transparency are maximized. The “see-through” soundstage that ESLs produce is always impressive, but with the Model One it was amazing. This transparency lets you discern the layering of the performers that is difficult for electrodynamic speakers to do – certainly more layered than my B&W 800D. This contributed to very good image specificity, even with front-ends that weren’t particularly good at that. I’d say the Ones are in the small cadre of the most transparent speakers I’ve heard through the midrange and into the highs. The Model Ones also created a soundstage that began a few inches in front of the speaker plane and went beyond the front wall, creating sonic images that allowed you to close your eyes and easily imagine the live performance. The stage was also extremely wide. “Spacious” is the word that inevitably comes to mind. With orchestral music these two characteristics produced a panoramic, dreamlike presentation, as though I was sitting in Row 7 Center in Orchestra Hall.

Speed. What can I say? ESLs are generally fast, and the Model Ones are no exception. I hate to give you the rehashed phrase, but it’s true: “lightning-quick” is the best description.

Where’s the Big Head? This was one of the issues that bugged me whenever listening to ESLs. I loved the realistically-sized and arrayed orchestras, but when I listened to small combos with a vocalist, the vocalist’s head was 2-3 feet wide. This might have been ok if all the other instruments were similarly oversized, but the ‘stats got those instruments right, inflating only the singer. Some readers might think that I’m overstating this characteristic of some ESLs, but it bugged the hell out of me back then. Since that time I have listened to ESLs that use multiple smaller panels or other techniques to normalize solo vocalists. Well, I’m happy to report that this issue does not plague the Model One. Everyone and everything is properly sized and placed, and you can definitely suspend your reality and believe that performers are in the room with you.

Top End Extension. The highs were very extended, but didn’t pop out at the listener as is the case with some speakers that have extended treble. I hear speakers that have extended top ends that to me are simply irritating. Perhaps I have too many bright recordings, but I find that many “extended” treble speakers grate my ears. I prefer an extended but decidedly unaggressive top-end. I thought the Model Ones got it perfect, with an extension that was stratospheric but controlled.

Midrange. Wow. Incredible. Compelling. Realistic. Gorgeous. I’m not exaggerating. If I wasn’t performing a review that requires some detail I’d simply stop after the previous sentence.

Bass Integration. If I did not know, I would never have guessed that this was a hybrid. The bass integration is totally seamless, and an unknowing listener could easily conclude that someone has designed a technique to make a reasonably-sized ESL with excellent bass. In my opinion this is quite an accomplishment. I have spent years attempting to integrate subs into all-electrodynamic speaker systems and could never get to integrate as well as the Model One’s woofers with the electrostatic membranes.

Bass Extension. I did not expect to get great bass extension, but I was pleasantly surprised that the Model One’s 8” woofers easily get to the 30-32 Hz range, and the bass stayed articulate at all volume levels. It will not hit the lowest of the low, but neither do my B&W 800D (which appear to me to be very conservatively rated). Except for some pipe organ music I tried, I never felt a want of extension in the bass.

Bass Weight and Slam. The one thing that the Model Ones didn’t have in spades was bass weight and slam. This is something different from bass extension. (Doug Schroeder, in his Dagogo review of the King Audio King ESLs, used the word “gravitas” to describe this characteristic.) Many people do not notice this characteristic unless they make a direct comparison to speakers that do have great weight and slam. My 800Ds have it in their present configuration, and there’s a pretty clear difference in this department. Every musical genre has tunes where weight and slam are part of the musical message that the artist is trying to convey; but rock, with its electric bass and synthesizers, has the most: Pinball Wizard by the Who, LA Woman by the Doors, 7 Nation Army by the White Stripes, War by Edwin Starr and Elevation by U2 are all examples – they all have passages that are designed to penetrate your gut and traumatize it. If you’ve seen any of these performers live in concert you know what I mean. That’s the only thing that the Model Ones can’t do. For that you’ll need to get some subwoofers and an electronic crossover and work your way through the difficult task of subwoofer integration. Happily, you will only consider doing this if you’re a fanatic and your family has the tolerance for that kind of thing. Otherwise, the Model Ones will do you just fine. And if you don’t listen to that kind of music anyway, just buy the Model Ones and don’t worry about it.

By the way, it certainly would have been interesting to try the powered long-throw woofer option mentioned above. That could make comparison to other top speakers really interesting.

An Observation and a Suggestion

There are those among us who will not like the sound of electrostatics; there is nothing wrong with that. Some will simply not like the somewhat ephemeral nature of the performers and the soundstage. However, if you’ve eliminated ESLs from consideration in the past, I have a few suggestions. First, try to give them multiple listening sessions. Second, ask the dealer to set them up with electronics that are powerful and that have a full-bodied sound. For example, powered by the Plinius Reference amps in monoblock mode (review to come) and the MBL 6010D connected with Aural Symphonics Chrono interconnects, the Model Ones were fast but full-bodied and created a very convincing soundstage. I was able to vary the ultimate weight of the presentation by substituting front-ends that had different characteristics – with the Electrocompaniet EMC-1 UP CD player (review to come) being the weightier, the Marantz DV 8300 having a lighter touch, and my modded Esoteric combo being right in between.

My Nits

My nits are not about the Model One’s sonics. Except for the fact that they don’t have the weight and slam of top electrodynamics, the Model Ones are in all respects elite speakers. My nits are on a couple of the functionality aspects.

The Model One’s speaker terminals are recessed for appearance’s sake, but that makes them very hard to access. As a consequence, you can only use banana plugs on them, and all my speaker cables have spades. In fact, none of my audiophile buddies use bananas – all use speaker cables with spades. This means that you’ll likely need to get your cables reterminated, because I don’t think that you’ll want to use adapters after spending serious bucks for the Model One.

The other thing that did not initially bother me, but became annoying over time, was the protection circuit indicator lighting. The changing of the lights as you approach the level at which the protection circuit is engaged became distracting over time. Moreover, when the light went red I found myself (a) trying to see if I could hear a difference, hence distracting me from enjoyment of the music, and (b) worrying about the safety of the system (even though David Janszen had specifically told me that I had nothing to worry about when the light went red).

David told me that he is thinking about making some changes to both of these features of the Model One.


I can’t say that I’ve heard more than a handful of ESLs, although I’ve heard a few very good ones, as well as a lot of other types of speakers. In my opinion, the Model One merits comparison to the best speakers available. It is not a question of whether they are very good or not. The only questions are: “Just how good are they and will they suit my taste?” This can only be answered by direct head-to-head comparison with the best speakers out there. If you’re able to spend $25,000 or more on speakers you need to audition the Janszen Model One, even if you were not thinking about ESLs. Highly recommended.

Manufacturer’s Comment:

First, I must thank Ed Momkus for both his well informed and eminently readable article, and for being such a genial host during setup and retrieval. Now, I’m glad to report that the JansZen nit exterminator has come up with two salient developments.

First, the speakers can be ordered with binding posts positioned within easy reach at no extra cost.

Second, there is now a switch on the rear panel that entirely disengages the multi-colored overvoltage warnings. It also dims the other functions of the indicator LED, which are namely to indicate when the power is connected, and also when the speaker’s bias voltage has been turned on or off by the signal sensing circuit. If you’re hearing only bass, the indicator should put your mind immediately at ease by revealing that the cause is a lack of power to the bias supply.

The protection engagement indicator will remain connected, although to more subdued effect. I think this is good because, if you do hear a change in the sound when the protection engages, there will be no mystery as to the cause, and the LED gives a convenient guideline when finding the max volume setting.

For whatever it is worth, aside from offering the option of powered, long throw woofers for the One, we have a subwoofer under development that is designed to mate with JansZen speakers and minimize setup hassles. In either case, you will find your belly shaking in a most satisfying way. Personally, I listen to some types of music with a prototype subwoofer added to my own pair of standard Ones. This gives weight and slam while retaining the optimal transient response of the One’s standard woofers. If you’d be planning on using another company’s outboard subwoofer, I’d just say to make sure it’s a model that can be rolled off above 30 Hz and can generate high SPL below that frequency.

David Janszen

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