Electrostatic speakers can do special sonic things. And perhaps no manufacturer has done more in the past few decades to bring these special sonic attributes to the consumer than MartinLogan. Today, we’ll look at some of the early history of the company, with some reflections on personal experience and excerpts from an interview with founder Gayle Sanders.

Those of us who have been in the audio business for decades can almost always tell you about seminal or “life-changing” audio experiences they’ve had. Usually these involve hearing a new piece of gear that allowed a very different and mostly better experience – generally getting closer to “the absolute sound”. Reviewer Jon Valin and I share this experience of the Magneplanar Tympani 1-D. I have discussed on our YouTube channel my experience with IMF transmission line speakers. The Audio Research SP-3a wrought some similar impressions (in my case demonstrated by Dan D’Agostino who went on to found Krell and D’Agostino Master Audio Systems).

Then some of us found the MartinLogan CLS. It delivered a level of sonic transparency that was, frankly, astonishing.

I should back up a bit to explain this. Electrostatic speakers create sound in a different way than normal cone-type speakers. In both cases, a diaphragm is used to move the air back and forth to create the sound waves your ear and brain can hear. But a cone speaker moves the cone by pushing on it near the center of the cone with a wire voice coil. The voice coil is in a magnetic field and the electric signal from your amplifier runs through the voice coil. When electrons flow back and forth through a wire in a magnetic field, the voice coil moves back and forth, pushing the cone back and forth. The cone must be stiff to minimize distortion across its surface.

In an electrostatic speaker, we have a thin flexible diaphragm instead of cone. The diaphragm is usually made of polyester film. The film is coated with a conductive material. This conductive material is charged to a high, constant level (this is why electrostatic speakers are almost always plugged into an AC socket whose energy is the converted to DC to charge the diaphragm). In front of and behind the diaphragm are two metal grids called stators. The stators get the music signal from the power amplifier and their varying voltage attracts or repels the charged diaphragm to move the air at the frequencies of the music so that your ear can hear it.

Several elements tend to result from this. First, the electrostatic diaphragm is driven across its entire surface. This allows the diaphragm to be lighter because it doesn’t have to resist bending from a force applied in just one place (i.e. ~the apex of the cone). A=F/M, so the theory suggests that low-mass electrostatics could be more responsive to small signals. Second, partly for historical reasons, cone speakers have tended to be placed in a closed box and electrostatics have tended to be set up in a dipole arrangement (sound emanates both front and back). Dipoles have various advantages and disadvantages; dealing with the disadvantages while preserving the advantages is the foundation of much of the history of electrostats.

In the early days of modern audio, which I’ll say is the  late 1950s and the 1960’s, two great electrostatic speakers were developed and marketed. The first was the Quad ESL 57. It was a short, wide speaker than was the source of many an audiophile’s “a-ha” moment. Beautiful midrange, a significant bass roll-off, and very strict and low-ish volume limits. If Helen of Troy had “the face that launched a thousand ships”, the Quad ESL 57 was “the speaker that launched a thousand audiophile journeys”.

The other great electrostat of the 1960’s was the KLH 9. Designed by Arthur Janszen, it was a big and expensive endeavor to get around the limitations of the Quad. Unfortunately, KLH had a brilliant design team but needed funding to grow and, well, the Singer Sewing Machine company perhaps didn’t fully comprehend the marketability of a $2280 speaker in 1968 dollars (that’s about $25,000 per pair today) and production was eventually stopped. J. Gordon Holt reviewed the KLH 9 in Stereophile in 1966 and we’ve put a link to that review in the description. One excerpt to flesh this epic saga out: “This was the first time, since we started dabbling in high fidelity in the early 1940s, that we have ever felt we were really listening through a loudspeaker instead of to it; the system has a degree of transparency and detail that we simply did not believe possible.”

Which brings me to the MartinLogan CLS. It was released in 1986, fully 20 years after the KLH 9. As happens often in technology, much of the period of wild invention (let’s say 1955-1975) is followed by a period of technological refinement. The CLS landed in the market after a decade or so of useful refinement. It landed on a group of audiophiles many of whom had missed the short-lived attempts at state-of-the-art designs like the Quad, the KLH 9, the Dayton-Wright, the IMF and the Tympani 1-D.

I first heard the CLS at Audio Consultants in Evanston, Illinois. It was priced at $2490 per pair, which is about $6500 in today’s dollars. I hadn’t read JGH’s review of the KLH 9, but the same feeling hit me like a ton of bricks: listening through the speaker to source instead of listening to the speaker. This was so obvious that it didn’t require effort or 100 tracks to find it. This transparent quality was just there. But, because the CLS had the standard dipole bass roll off, and maybe some brightness in the upper midrange or lower treble, again those darn ships set sail for Troy, or wherever audiophile wars are fought.

Now, let’s look at Dick Olsher’s discussion of MartinLogan history from The Absolute Sound’s Illustrated History of High-End Audio:

The early years of Martin-Logan were focused on experimentation with conductive coatings, insulation, adhesives, perforated steel stators all elements needed to make the speakers reliable and capable. And, of course, founders Gayle Sanders and Ron Sutherland worked on the curvilinear line-source panel (CLS) to improve dispersion. The CLS was a conceptual breakthrough and is now a fixture in every MartinLogan electrostatic design. Some said that a curved panel wouldn’t work, but we’re all grateful to MartinLogan for exploring the road less traveled.

            Over the years MartinLogan strove to improve its core technology, the electrostatic transducer, by continually researching new materials and methods to improve conductive coatings, insulators, adhesives, and assembly processes. This continuing evolution has resulted in improvements to bandwidth, efficiency, consistency, and reliability. The electrostatic panel of 1983, while looking similar, is vastly different from its contemporary counterpart. For example, in 1983 conductive coatings were hand applied with a conductive slurry. Today, conductive coatings are applied to the diaphragm through a proprietary vapor deposition process in a state-of-the-art vacuum chamber that allows the diaphragm to maintain a 5,000 volt charge.

            What motivated all this experimentation was that audiophiles wanted (and still want) full-scale reproduction of both dynamics and bass response. After significant experience with all variations of both ESL and dipole technology, MartinLogan had to face the reality that dipoles, and ESLs in particular, are challenged when asked to reproduce both large-scale dynamics and low-frequency information at the same time. So, ML decided early on to design a high-efficiency electrostatic transducer to be integrated into a hybrid system. That first speaker was the Monolith and it launched the company following an encouraging reception at the 1983 CES. Sales took off in 1985 placing the company on a firm financial footing; that was also when Ron Sutherland departed MartinLogan to pursue his first love, electronics.

            The first full-range electrostatic speaker, the CLS, arrived in 1986, as we discussed. That appealed greatly to experienced audiophiles. But it was the Sequel, a smaller hybrid introduced in 1987, that resulted in explosive sales. During the 90s product releases came fast and furious and included some of MartinLogan’s classic models such as the Quest, Aerius, and SL3, and to top off the product-line with a claim on state-of-the art honors, the massive Statement e2 loudspeaker was released in 1998.

            The release of the Summit in 2005, followed by the Summit X in 2009, heralded the arrival of the most advanced hybrid yet, combining dual independently-powered woofers with MartinLogan’s most advanced electrostatic transducer to date, the XStat^TM. Extending the history of extreme purist models, The CLX Art, unveiled in 2010, was its most advanced full-range electrostatic.

The TAS Interview wth Gayle Sanders

TAS: When did you first become passionate about music as well as reproducing the live experience in the home?

GS: Music was a part of my life since I can remember. In my family there was always piano and singing, and records from classical to rock to jazz and blues. I got into performing early, first in an a cappella choir, then in folk, jazz, and finally rock groups. I played professionally from the age of 13 on through college, where I worked with a number of small jazz ensembles and rock bands of all shapes and sizes, paying for the majority of my college expenses.

TAS: As we understand it, you met up with Ron Sutherland in the late 70s. What brought you together and led you to try building a better electrostatic speaker?

GS: When Ron and I first met we shared a common interest in music and despite our different backgrounds we quickly became friends. I was a musician trained in architecture and advertising; Ron was an electrical engineer and degree’d physicist. We soon discovered that we also shared a passion for developing audio designs. I told Ron about my dream of creating a real electrostatic loudspeaker and he immediately jumped in.

At the time I had developed a basic ESL transducer. It wasn’t pretty, but I was close to actually making it work. Ron had just the right talents to help me achieve that. That’s what brought us to start MartinLogan. So in 1979 Ron and I organized a small design team committed to overcoming the many difficulties that came with electrostatic speakers. Though by this time the efforts of some incredibly skilled engineers had resulted in some very good electrostats, no one manufacturer had completely resolved the puzzle of how to perfect them. I was naïve enough to think that I might just be the one to “crack the code.”

ESLs had the reputation for being bass shy, easy to blow up, extremely amplifier critical, beamy and directional, and, let’s not forget, hampered by significant SPL limitations. Even with those limitations, when one listened to a well-designed ESL, the jaw-dropping transparency and “you are there” ability of this lovely technology was addictive. I was convinced these problems were a result of the engineering and materials application of the day and could be overcome. In all my research, it was clear that the physics behind ESLs had few limitations if only one could find the right materials to control this sometimes terrifying technology and knew how to work within the specific requirements of a super-high-voltage, low-mass system.

TAS: Please describe the early years of experimentation that led to the first ESL prototype circa 1980.

GS: It was the classic entrepreneurial story. My “lab” (I use that term very loosely) consisted of a makeshift desk made out of an old door resting on a pair of sawhorses. Sitting in the corner of my garage, equipped with a rotary phone, pencil, pad of paper, a stack of ideas, and a bunch of tools, some of them handmade just for the project, I began talking to scientists and engineers who might be able to help me. Many became fascinated by the project and offered useful suggestions, and the lab quickly developed into a working shop outfitted with the raw materials I would need to prototype an advanced electrostatic transducer.

After six months of building a prototypes only to have them fail time and again, I finally had what I thought would be the first working transducer. God it was ugly, but I loved it. By that time, Ron had joined me. In a very short time he designed the transformer and power supply based on the transducer’s electrical properties and the efficiency we had determined it could potentially deliver. It took many more months before I devised a perforated metal structure with sufficient efficiency and rigidity, sourced the optimal film for lowest mass/structural integrity, and found material and adhesives for spacer elements that had the necessary insulating properties and tensile strength. For the prototype I only needed to make the diaphragm surface conductive, so I smeared a concoction of Graphite powder and my own personal magic dust on the diaphragm in order to energize the surface uniformly (4000V—yee hah!). I had coated the metal panels with “rid arc” hoping that it would be enough insulation to allow the system to actually perform without blowing up.

The moment had come! We anxiously hooked the interface transformer to my trusty Hafler DH-100 amplifier. I can’t remember the preamp nor the turntable, but I do remember when we first dropped the tonearm onto the record. Was it Joni Mitchell? Maybe. All I can remember is at that moment the most magical music flowed from that object. It was everything I had dreamed. The curtains pulled back and transparency incarnate presented itself. Ron and I were both at once yelling, crying, and hitting each other. Then I uttered those fateful words… “LET’S TURN IT UP!” At once, there was a loud explosion. As I gawked a ball of flame engulfed the transducer, and then …silence, followed by a blue-grey puff of smoke that lingered in the room to remind us how naïve we were and of the dangers that lay ahead. My poor Hafler had a puff of smoke lingering above it too. It was very quiet; all you could hear was the mechanical scratching of the stylus through the record grooves. I lifted the tone arm. Maybe tomorrow.

TAS: Improving horizontal dispersion must have been a R&D priority in those days. How did the curvilinear line-source (CLS) transducer central to the design of every Martin Logan electrostat come into being?

GS: After we had developed a rugged, no-compromise transducer, we still had to solve the significant dispersion problem that all large-surface transducers pose—specifically, that the higher frequencies become progressively narrower and narrower in dispersion. The result is that only one person can experience the full frequency range, and that person can’t move. It’s so limiting that the phenomenon became known as the “head in the vice” listening experience. One evening Ron and I were debating how a “point source” wave-front behaved at higher frequencies compared to one that radiated from the relatively large surface of our diaphragm. Ron began diagramming a progressive arc that became more and more curved as it moved forward in time and space. That was the “aha” moment for me. Could it be that simple? Could one simply mechanically mimic that arc in space and get uniform dispersion? I set to work that night to make a jig to both curve the diaphragm and stator elements in as exacting a way as possible. The next few days were spent refining the fabrication process. Finally we had the first curvilinear ESL transducer. The results were just what the doctor ordered. We had uniform horizontal dispersion, yet it was well controlled in both the vertical and horizontal plane, minimizing and offering even better control than the point source as it behaved in the room.

TAS: When did you finally feel secure about your business decision?

GS: That took awhile. I had worked so hard for three years to create the Monolith, but now an entirely new struggle was about to begin. For the next three years, the fledgling company faced every teething pain you can imagine. There was no relief. One-hundred-hour-weeks, product failures, cash flow crises. We faced bankruptcy on a regular basis. The only time I could take a breath was to lock myself in the bathroom just to lift the burden for a few minutes. On one particularly bad day, one of the real high-end founding fathers called me. Out of humility he probably doesn’t want me to mention his name, but let’s just say there was a time when he made amplifiers in a coffee can. Anyway, he asked, “So Gayle, how’s it goin?” I was in no mood to bs that day and asked if he wanted the truth. “Let me have it” was his response. I proceeded with a litany of painful retorts. “That’s just not right!” came the voice over the phone. “How much do you need to get through?” I told him a hefty number to which he responded: “Check’s in the mail.” The next day the money was direct wired into the MartinLogan account. That saved the company. One of my best days was many months later when I was able to finally pay that money back.

Work really heated up on a smaller hybrid we called the Sequel, and finally the day came that ML introduced it into the world. It was just the right speaker for the times and it took off with explosive sales. Once we released the Sequel, it was like a power boat planing out. Things got smooth. The ML team now was a well-oiled machine and could execute with ease. Cash flow became positive. So finally, after six years of sacrifice and struggle, life became fun. ML started to rock and never looked back.

TAS: As you look back over an audio career that spans over 30 years, which highlights jump out at you and which milestones are you most proud of?

GS: I remember walking the halls at the ‘82 CES convention and thinking ”Hey, I’m one of the new guys” in the industry. It was an exciting time and great companies were coming into being. We all were consumed with our vision, and together created an exciting, engaging, superior standard of excellence in performance. As an industry, we avidly read J Gordon and Harry P’s words on the journalism side, as we crafted and perfected our products. It was a generation of young renegades out to change the face of sound reproduction. And it was a wonderful time in which to create.

Naturally, that first moment when I integrated the first working high-efficiency ’stat panel and a high-performance woofer (the predecessor to the Monolith) was thrilling. We were in a small listening room. It had been years in development. Immediately, the transparency and slam was jaw-dropping. I had only experienced that moment of wonder with the Infinity Servo Stats before. I will never forget that feeling. I was stunned. That moment showed me that I truly had something to contribute to the audio industry.

Toiling away in that same room night after night a few years later resulted in the creation of the CLS. I couldn’t wait to share that with the world. And finally, the moment the Sequel entered the market I knew we had a true winner. The right product, the right price, the right time: a true commercial success. And to see ML’s success sustained over the years by the team of talented and committed young men and women that I’ve trained and mentored, that’s enriched those memories in the most satisfying way I can imagine.

MartinLogan in The Absolute Sound

CLS

“Overall, then, the MartinLogan CLS withstands the test of time in exemplary fashion. Its only significant shortcoming is the lack of deep bass. Other than that, it is a world-class speaker system.” —John Nork, Issue 46

Sequel

“Dollar for dollar, I consider this the best speaker in High End speaker systems. It represents the mating of an electrostatic midrange/high-frequency panel with a conventional ported enclosure, containing a conventional cone-type woofer. I am told that dealers sell this speakers almost before it’s unpacked, and I can well understand why. If I myself were on a budget, it would most likely be, with some reservations, the speaker I would choose to live with.” —Harry Pearson, Issue 57

CLS II

“Sanders has done his homework. Today MartinLogan is a “force” in High End circles, just the way Magnepan was a decade ago. The CLS II is aesthetically neat and sensible, fascinating and serious; musically brilliant.” —Andrew G. Benjamin, Issue 62

Sequel II

The MartinLogan Sequel Series II loudspeakers come as close as anything I’ve heard to succeeding at the gnarlsome enterprise of fusing a cone woofer with an electrostatic panel. The things really do display the transparency of the latter with the taut control of the former—and pretty seamlessly at that.” —Fred Kaplan, Issue 64

Source

“How does the Source sound? In a word, terrific. This is one very quick, very high resolution, surprisingly robust, wideband, and coherent loudspeaker, capable of making select voices and instruments sound as you-are-there “real” as some multi-thousand-dollar Big Boys. If you haven’t heard a MartinLogan electrostat in awhile, you kind of forget just how astonishingly lifelike they can be. Despite the fact that all ’stats use the same basic drive system, panels from different companies sound as substantially different as dynamic loudspeakers from different companies. Logans are fast, fast, fast—and transparent, as in “clear, pure, uncolored.” Hearing plucked guitars or violins played back on CLSes always made everything else, even other ’stats, sound slightly stuck in the mud. It’s no different with the Source. Only the Source is far more realistically dense in tone color and far more full-bodied and three-dimensional than the old CLS.” —Jonathan Valin, Issue 180

CLX

“. . . I’ve never heard a loudspeaker that’s as transparent as this one.” —Jonathan Valin, Issue 190