MSRP = $12,999




The Sanders 10b is a hybrid electrostatic/magnetic speaker with the electrostatic panel handling the mid and treble and a conventional cone/transmission line bass cabinet. The system includes an external 330 wpc stereo amplifier specifically for the bass cabinets that includes an electronically adjustable bass and midrange via the included universal remote control. This review includes an optional separate amplifier for the electrostatic panels that puts out 1700VA/channel or 400 wpc at 8 ohms.

A note about his review; it is unusually long. Part of what Stereomojo is all about is education. We believe an informed and educated reader is more likely to make better decisions in regard to his audio purchases, resulting in more enjoyment and less money wasted. True electrostatic speakers are not common (not all planar speakers are ‘stats) and not widely sold on stores. Most people know little about them. The same is true about the specific product in this review and the person behind it. We believe it is important to inform you about all these facets. We also realize that many of you are reading this in your office or some other time sensitive place, so if you just want to read the review and skip most of the background, click here and we’ll take you there.

Have you ever heard of Rodger Sanders? Or his speakers? Or amps? He’s only been in the audio industry for about 40 years. He has been making and selling speakers and electronics for almost as long and there are many people who think his products are among the best, if not THE best you can get. Why is he practically invisible? It could be that he is a rebel, and an outspoken one at that. He has very strong opinions born out of four decades of work, study, trial, experimentation, failure and success. His opinions, like ours, go against those that are so deeply entrenched in the audio industry and supported by the audio press. Take this statement for example: “I believe that most high-end, audio products are priced at unconscionably high levels. Not only is this unfair to consumers, it is damaging the reputation of the entire industry”. Ouch. But he doesn’t stop there; “Examples of this include tiny amplifiers selling for prices in excess of $20,000 and speaker cables selling for thousands of dollars. There is no way that the parts, performance, or design costs of these amplifiers or cables justify such prices. This is particularly true in the case of small amplifiers, because they cannot drive loudspeakers in a typical home environment to realistic levels without clipping. I believe in designing and selling products of real value for a reasonable price”. We agree. We don’t want to imply that Roger is the only one who believes the way he does and proves it in his products. We have introduced you to several others. It’s just that people like him don’t get enough exposure in the mainstream audio press and have, in fact, been shunned over the years.

One of the main reasons Stereomojo was created and exists today is because of people like Sanders and the products he makes. Stereomojo searches far and wide to find people and products that publications like Stereophile and The Absolute Sound routinely ignore. Small companies don’t have the $20,000 it takes to advertise in them so their products aren’t going to be reviewed for the most part. Yes, they sneak in a few to keep up appearances and give themselves something to point to when the obvious connections are pointed out, but it is a fact that in many print and online publications, reviews are directly tied to advertising money which leaves small companies out in the cold. It’s people and products like Sanders that make the trails and tribulations of publishing Stereomojo worthwhile.



Roger Sanders may be the most knowledgeable person on the planet when it comes to electrostatic loudspeakers – let’s call them ESL’s. His first published article on ESL’s was in 1974, followed by another on amplifiers to drive ESL's in 1976. His contribution to audio include the invention of the curved, free-standing, electrostatic loudspeaker driver, the development of extremely compact transmission line woofer systems, integration of electrostatic speakers and transmission line woofer systems and, several "how to" construction articles in "The Audio Amateur" and "Speaker Builder" magazines.

Roger's greatest contribution to the state-of-the-art is his book, "The Electrostatic Loudspeaker Design Cookbook", published by The Audio Amateur in 1993. Written for the audiophile craftsman rather than the engineer, this treatise is a definitive set of instructions, explanations, and, arguments for achieving the most accuracy and realism possible. Since that time, he has never stopped experimenting and improving his driving passion of the consummate speaker and the amplifiers that best drive them to their ultimate goal.





An electrostatic speaker is almost the opposite of a standard electromagnetic speaker; you know, the kind with cones in a box. Roger explains: “Unlike conventional speakers that use magnetic forces to move a relatively heavy cone, electrostatic speakers use high voltages to move an extremely thin, light diaphragm. High voltages produce an attractive force similar to magnetism. You may have discovered this by combing your hair on a dry day. The comb takes on a high voltage charge and you can feel it pull the hair on your arm or watch it pick up dust or small bits of paper. Note that this charge is STATIC (it doesn't move). In an ESL, a small, high-voltage power supply puts a static charge on the speaker's diaphragm. Hence the name, electroSTATIC loudspeaker. This is also why the speaker must be plugged into the wall like any other electronic component. On either side of the speaker's diaphragm is a STATOR, an electrically conductive, acoustically transparent grill. The amplifier is connected to both stators through a high-voltage step-up transformer. The transformer is necessary to raise the voltage of your amplifier from a few tens of volts to the several thousand volts needed to drive the diaphragm. Music causes the amplifier to deliver varying amounts of electricity to the stators.”

So how does an ESL actually produce music? “Like north and south magnetic forces, positive and negative electrostatic forces are attracted to each other, while similar polarities are repelled from each other. Music drives the amplifier to produce a positive voltage on one stator and a negative voltage on the other. These voltages alternate back and forth between positive and negative very rapidly to produce a tone. For example, "middle C" on a piano has a frequency of 256 Hz (Hertz). That means the polarity on the stators will alternate 256 times per second. The amplifier also alters the voltage as necessary to make the music a particular loudness.

Now, let's look at what is happening inside the speaker to make it produce sound. At a given moment in time, in response to the musical signal, let's say the front stator has a positive voltage. The rear one will be negative. Let's assume that the diaphragm has a negative voltage. Remember that the diaphragm's voltage is static and comes from the little power supply and does not change like the voltages do on the stators. The negatively charged diaphragm will be attracted to the positively charged front stator because opposite charges attract. It will be repelled from the negatively charged rear stator because like-charges repel. A moment later, the amplifier will reverse the voltage polarity on the stators, so the diaphragm will move the other way. As the diaphragm moves, it produces pressure waves in the air that we hear as music”.

Like every speaker design, there are advantages and disadvantages. In general, history tells us that an ESL has these advantages:

There are no cabinets with an ESL panel, so there is no cabinet resonance. Cabinet resonance is a huge factor in speaker design and much of the cost of a good speaker is sunk into the cost of designing cabinets that minimize resonance. Exotic materials like aluminum and even granite are used. Other costly formulations are devised. Internal bracing is expensive. Once they are designed, building them is very expensive and time intensive as well.

Speed. Because there are no big heavy cones to start and stop (or to break up), only a very light, thin mylar-like diaphragm, the very instantaneous beginnings and ends of note and sounds are reproduced in a way standard cones simply cannot. Think of a gazelle being chased by an elephant or a battleship trying to catch a fighter jet. Or Roadrunner vs. Wile E Coyote. Conventional speakers have tried to catch up by using exotics like Kevlar, aluminum and even ceramic cones to lighten them up, making them easier to start and stop and not distort. All have their own colorations and all can be pretty expensive.

Midrange purity. Most people who have experience with electrostats will tell you that they do mids better than anything else. Take the Quads for example. Many people, including reviewers, swear by them even though they are very flawed reproducers in many ways, but their midrange, where the majority of music is located, is superlative.
Big image and soundstage. The ESL area that radiates and actually produces sound is much larger in square inches than a speaker of a similar or even much larger size with cones.
There are only three US companies that make ESL's. So why don’t more people make electrostats and why don’t more people buy them?



That’s simple. In the past, electrostats have had some severe limitations and more downsides than upsides and. Among them are:

Limited bass response. To fix that, hybrids are necessitated that add a conventional cone woofer for lower frequencies, but they never quite match the sound or speed of the electro panels.

They don’t play very loud. They have been rather fragile and prone to damage if overdriven, or underdriven for that matter. Even the newest Quads are notorious for limited output.

They have to be plugged in and require a long time to “charge up” before they sound good. Some say as long as an hour. Not conducive for “right now” listening.

They are hard to drive. Their sensitivity is low and their impedance can range from very low to extremely high making them very incompatible with most amplifiers. Conventional speakers present a mostly resistive load to an amplifier while an ESL appears mostly as a capacitor. Most amps are designed to accommodate resistance, not capacitance, so they are two very difference animals. You know that amplifiers are rated in watts, right? An ESL doesn't operate on watts, it operates on voltage. Offering watts to an ESL is like offering a glass of water to a vampire; it’s not really what it wants or needs to live. Literally, a conventional amp that is rated at 500 wpc may not have the juice to effectively drive a pair of ‘stats. That’s why Sanders also makes an amplifiers that are specifically made to drive voltage hungry ESL’s.

In addition, ESL’s have been known to be very sensitive to their environment. Humidity is an enemy. So is dust and any other airborne detritus like bugs or dog hairs. Ever notice how your TV screen attracts dust? So do the highly charged ES panels. They have been known to arc like a bug zapper.

Then there is the sweet spot. It’s always been small. Tiny. Almost microscopic. Once you locate it, if you move or turn your head it’s gone. Early ESL’s came with neck braces to keep your head precisely in place! No….that’s not true. But in some cases you might have needed one.

ESL’s have never been very flexible when it comes to tuning or shaping the sound. There might be a level on the conventional low-end box, but that was it.

Then there is the cost. ESL's have never been particularly cheap. They still aren’t, but it may be that you get a lot more for your money now than you did a decade or so ago. That’s what we are about to explore.




You notice that I started this section saying, “In the past, electrostats have had more downsides than upsides.” That’s because Mr. Sanders’ forty years of research, trial and error has paid some pretty big dividends. Many, but not all, of the “bad” elements noted above have either been eliminated or minimized substantially.

According to him, with his ESL’s:

You can listen cleanly at 100 DB levels with correct amplification
The amplifier cannot damage the panel. No protective circuitry required
Goes down to 20 Hz
Bass and midrange is adjustable – even via remote control from your seat
Panel is arc-proof
Extremely rugged and durable
Immune to dust and dirt. Actually repels it
Immune to humidity
Unaffected by insects, dust, and foreign objects
Higher efficiency – greater than 90 db
Does not require long periods to charge up – can even be left on continuously

He does not claim to have a wide sweet spot so that is not solved, but is it any better? And his speakers still require voltage and as such are still not easily driven by some amps. That’s why he makes his own.

Speaking of amplifiers, the 10b’s are bi-ampable. Bi-wire, too of course, but they are designed to be driven by two different amps. Rather uniquely, one amp is included in the price. The Sander’s 10B is really a system more than just a speaker. In a separate chassis comes a 330 watt per channel stereo amp. “Hold on”, you say. “Didn’t you just tell me that ESL’s don’t like watts and need more voltage”? Aha! So you were listening! But, the amp included with the speakers is only for the bass bins which are conventional cone speakers, not ESL’s. They like watts, so we are fine. You need to provide your own amp for the ES panels (mids & treble) or buy the optional one used in this review which is designed for the type of loads ESL’s present.


The box you get with the speakers is much more than just a bass amp – it is also a very sophisticated fully balanced preamp with separately adjustable bass and mids via the also very spiffy universal remote. Backlit and everything. It can be programmed to operate every component in your system – audio and video. It controls both the internal bass amp and the other amp powering the panels. I cannot tell you how great it is to be able to sit in my chair and make minute adjustments to the low bass or the midrange levels and hear them in real time while the music is playing. A couple of quick tweaks and recordings that usually sound thin are brought to life and/or others that are either too heavy or too weak at the very bottom are transformed. Of course, you are also able to set the speakers so that they match your room almost perfectly for normal play and then make your micro adjustments from there. Just make sure to jot down your settings because if you turn the controller/amp off, it looses its settings and goes back to the defaults.

The amp/controller can also be used as a preamp – as long as you only have one input at a time. As much gear as I have, that was never a problem - I just decided beforehand whether I was going to listen to LP’s or disks for that session and moved the one pair of cables. No biggie. I had planned to use other preamps in front of the piece, but I never did.

I told you that this review was unusually lengthy, but I hope you appreciate why all that background was necessary for a thorough review. You are anxious to hear what they sounded like, right? Good. We are anxious to tell you!




I have a confession. Full disclosure. I have never cared much for the sound of electrostatic speakers. Also you should know that I have never had a pair in my system. However, I have heard them in various stereo shops and at many audio shows. The local Sound Advice, now shuttered and out of business, used to sell Martin Logan so I heard a lot of them over the years. The only pair that I almost liked were the big Summits – also a hybrid system with a conventional low end. The midrange for vocals was outstanding and it did play pretty loud with excellent dynamics, but solo piano sounded uneven and edgy. The low end did not match the mids and high end well. And, like I have always experienced with ESL’s after a few minutes, I wanted to leave the room. I have developed a very unique, sophisticated test instrument that tells me when a speaker is too bright or too harsh or just plain distorted. It’s called my lower jaw. It always confirms what my ears are telling me when it spontaneously tightens up and begins to ache. That’s usually what happens when I hear ESL’s, even a few Soundlabs.

However, something funny happened in Denver at the Rocky Mountain Show. Because of the severe time limitations at audio shows, I always make a list of those rooms, people and products I MUST SEE. Roger Sanders and his ESL’s was NOT on it. But, as I was walking down one of the many crowded, noisy, hot and sticky hotel hallways where every open door vents a blast of hi-fi sound, I went past a room that made me stop in my tracks – something that is not very smart or safe in the teaming traffic.

There was something highly unusual wafting from that room. It sounded like real music!

The room was rather stark and bare – not stuffed to the gills with gear like most. There was a single pair of speakers set up catawampus in the room on a diagonal with the right rear corner centered between the two tall, semi-transparent panels. A sign said “Sanders” and there was a guy sitting there with a nametag that matched the sign. I was not familiar with the name or the speakers. I handed Roger my card and introduced him to Linda. He sat me in the one chair that was set up as a listening position and started his presentation, extolling his products like everyone else does. He mentioned all of the features listened above, particularly the ability to play loud. He casually toggled the volume to ear splitting levels playing huge scale orchestral. The sound was pristine with enormous dynamics even at that near 100db level. He was not at all concerned about the welfare of his speakers with the fragile looking mylar panels. I handed him my custom Stereomojo evaluation disk. I listened to one track. Then another. I ended up staying in that room for a good thirty minutes – waaay too long for show reporting. And the next day I did something I seldom do. I came back. I listened some more and talked to Roger about his career, experiences and philosophies. I was impressed with his sincerity and no BS demeanor. I asked if his speakers had been reviewed. He said a print magazine had done a review of his older model when he was at Innersound years ago, but the guy didn’t even read the owner’s manual and thought the speakers were defective. Duh. I told him about Stereomojo’s approach, experiences and philosophies and asked if he would be interested in doing a review.

He looked me straight in the eyes for a moment before committing to a definite maybe. It was obvious he didn’t have much trust in the audio press.



The Sanders 10b system plus optional ESL amp arrived in 5 containers; three for the speakers and two for the amps.
Assembly is easy but it takes a good hour. Only one tool is needed and it (an Allen wrench) is included. You have to attach the upright frames to the wood bases and then the panels and wood trim attach via Velcro.

I placed the speakers in the standard starting point, an 11-foot equilateral triangle. The instructions are to aim the speaker right at your ears, so a toe in is required. There are four pages of text with pictures to help you position precisely. You will not see a better written, more intelligent and thorough owners manual, further evidence that Roger truly cares about his product and customers. He stresses that they must be equidistant from you.

In the manual he asks, “How precise should you be?” The answer; “The wavelength of a 10KHz tone is about 1”. And error of ½” will place this frequency a full 180 degrees out of phase, so ideally the speakers should be within a quarter wave. For 10Khz this would be 1/4” of being equidistant”. I learned this a long time ago. I always measure distance from the back wall exactly for the inside and outside of each speaker. Then Linda helps by holding a long wire firmly in front of her nose while I move the other end to identical positions on each speaker.

Precise distance is vital. Aiming the 10b’s at your chair could not be easier because the see-through panels with crosshatches look just like a periscope or an assassin’s long rifle site. To make the finest adjustments, you can use a flashlight because the mylar is reflective. Just sit in your chair and hold the flashlight above your head and get the reflection centered from side to side. Done.

I hooked up the bass amp/controller and the special ESL amp he had sent. He includes his own cables to run from the controller to the ESL amp. As usual, Roger throws in his expertise in the manual. “Some speaker cable has high capacitance and can cause high quality amps to oscillate at very high frequencies. You cannot hear this oscillation as it is supersonic, but it will cause the amp to operate at full power and can overheat and damage both the amplifier and the speakers. One brand of cable is notorious for (this) and that is Goertz (Alpha core) cable.”

Yikes! Do you have any of that? Also in keeping with his honesty, he goes on to say the he has designed extremely low inductance, moderately low capacitance and moderately high impedance which he says is what ESL’s prefer. BUT, he also declares that most other cables will be ok as long as their inductance is very low. Roger is not a greedy marketing monster. He just says things as he thinks they are. Like the power cables that connect the AC to the speakers. He supplies some and says that you can use any you prefer, but there is no reason to use special cables or power conditioners. How often do you hear something like that? Maybe that’s why Roger is not the most popular kid on the block in the audio press. Too much good sense.

I used my reference Kimber Selects running to the ESL posts on the back of the speakers. I went directly in to the controller from my Xindak tube DAC.

I did read in the manual where Roger says because his speakers are phase coherent and dipole (sound comes out the back as much as the front), they can be placed much further apart than normal, but I started in the default position. At the show, he had his demo setup pretty close together about like my initial position.

As I began listening to the Stereomojo evaluation disk, one thing became very apparent; there was no image beyond the edge of the speakers. Usually we hear sound well beyond the speaker’s outer boundaries as well as in front and way behind. You can see how they were positioned in the picture. I was not surprised; that’s exactly what I expected. But I wrote to Roger to

see what he would say about it; and so I could pass it along to you.

“James, there should not be any image beyond the outside edge of any speaker. But since wide dispersion speakers spray highs all over the room, the reflected sound will often cause you to hear sound from beyond the edges of the speakers as it bounces off the walls. Of course, the problem with this is that the sound has been delayed compared to the speaker's direct sound. The result is confused phase information that prevents the speaker from producing a 3-dimensional image. Wide dispersion speakers totally mess up the phase information by having a myriad of delayed room reflections. The image is so confused that you can hardly even tell when you are at the sweet spot. The laws of physics dictate that all stereo speakers have an infinitely small sweet spot (when you are exactly equidistant from both speakers). The idea that you can sit three listeners abreast and all can hear a perfect image is impossible. The fact that some audiophiles believe that some speakers have a wide sweet spot simply proves that wide dispersion speakers do not produce accurate, holographic images.”



Well. I’m sure most makers and owners of conventional speakers would disagree as far as not hearing accurate, holographic images. I certainly have as have every visitor to my home in both listening rooms. Now. Having said that, do I think the Sanders 10b is at least as detailed and accurate as any speaker at any price I have had in my system? Yes. Do I think they are possibly more accurate and holographic than any speaker I’ve had in my system? Hmmm. I don’t know about you, but one thing I really despise is when I see each month’s addition of Stereophile or The Absolute Sound and the cover screams “THE BEST (you name it) EVER”.Then you read the reviews and almost every single one ends the same way – “The best I’ve ever heard!” Then next month the cycle starts all over again. Needless to say, we religiously try to avoid such hyperbole. So, when it comes to the Sanders, we’ll just have to wait and see.

What I’m hearing with the speakers in a triangle is an image that is very constricted and narrow. There’s minimum depth and minimum width. Not good. The musicians sound like they are performing in a phone booth. So I moved them out. About a foot from the side walls but still precisely equidistant and toed in. This is usually a bad thing to do because it causes a hole in the middle and less precise imaging. Playing the Stereomojo disk again (do a link to a new page) sounded like I had installed a completely new system. The new stage was wide and deep with images so crisp, clean and clear that it was startling. A few minutes in and I began to laugh. Out loud. This only happens when I experience something incredibly and uniquely amazing and joyful. In audio, it’s only happened a couple of times. In live music situations it has happened much more often and I’ve had to do some serious stifling. Apparently every other reviewer in the world has some sort of facial affliction because when they hear something amazing their jaws always drop. Have you noticed that?

So the soundstage was outstanding, but imaging alone doesn’t elicit such enthusiasm for me. There must be something else going on.



Way back I reviewed a power amp by Luminous badged the KST-150. Its main claim to uniqueness was its speed. Baby, it was fast. Here’s what I said then: “The KST-150 is a stereo power amplifier whose rated output is (surprise) 150W RMS continuous into 8 Ohms, both channels driven over a frequency range of 20 Hz to 20 kHz with less than 0.1% total harmonic distortion. Pretty specific specs. The rest of the specs are also impressive, but the one that stands out the most is one not usually touted or viewed as all that important; slew rate. Slew rate represents the maximum rate of change of signal at any point in a circuit. Limitations in slew rate capability can give rise to non-linear effects in amplifiers.

The red trace represents a true square wave, the green the effect of a slow slew rate on its reproduction by an amplifier. I went on, “Slew rate for this amp is a claimed 250 volts per microsecond (vps). Think of that as "miles per hour" in your car. That amounts to near record setting speed in the audio world, and certainly the highest anywhere near this pricepoint. For example, Krell’s best power amp, the Evo 1 lists for $25,000 and has a published slew rate of 100 vps – less than half as fast. How does that 250 vps translate to sound? We’ll find out in a minute.”

I cited two cuts from the older version of the Stereomojo Disk: “I must digress for a moment. I am not a drummer, but I have played drums on occasion and I took a course required for my music degree called Class Percussion where one is required to learn to play every orchestra percussion instrument from snare drum to triangle to tympani. Flams and paradiddles. In bands in which I’ve played, I also on occasion sat way to close to the drummer where every chart sounded to me like a drum solo. I say that simply to state that I know first hand what real drums and cymbals sound like, feel like, and sometimes smell like – depending on the drinking/smoking/hygiene of the drummer. Cymbals, like every other instrument have a basic, fundamental pitch. Even on some very expensive amps and speakers, crash cymbals sound more like a short shot of white noise or the sound a wet finger makes when it touches a hot iron. So, it was with a great deal of surprise that the first thing I noticed when listening through the Luminance was that crash cymbals on the Tricycle cut were reproduced with their fundamental pitch intact. Hmmm. Even my Halcro Class D, 400 wpc MC20 didn’t do that as well, and one of the qualities of a Class D amp is supposed to be speed. Through the KST 150, cymbals did not sound like white noise and their long ring-outs were there, too. They had a real body and presence to them that was not an artificial boost in frequency. This seemed to warrant further exploration.”



And, “One of the most demanding recordings I know of for speed is “Friday Night Live in San Francisco” by Al DiMeola, John McLaughlin and Paco Deluca (SACD) – three of the best guitarists on the planet. Here they are live and executing some of the most incredibly jaw-droppingly fast acoustic guitar technique ever recorded. The 150 had no problem reproducing the lightening-like pick on strings sound – sometimes all 3 players simultaneously. “Lively” is an understatement. It was remarkable and left me almost breathless just listening to it. This quality was apparent in every recording and every genre I played; drums, plucked strings, anything struck and most thankfully, piano. That fast slew rate was slaying them all. You really need to hear this phenomenon if just once.”




I listened to the same two cuts over the Sanders stuff. Better. Much better. I threw in Winston Ma’s amazing Chinese percussion CD using the K2HD mastering from FIM music. “Yim Hok-Man – Master of Chinese Percussion”. When Winston sent me this disc for review, I almost sent it back to him unopened. I knew I wouldn’t like it. It sat in a pile for the longest time. The 10b system made me want to try it. If anything was going to make my jaw ache via the ESL’s, it would be this. Crazy good sonics as well as immense musicianship that made this the first Chinese music release I have not hated. I really like it. And it certainly is a great test CD for speed and frequency response. Winston Ma triumphs again.

Working with the Luminous taught me a lot about speed and how important it is to audio reproduction. While slew rate is not strictly a speed measurement (frequency response is part of the equation), working with the Sanders ESL’s I feel like I’ve been given a PhD in speed and how absolutely necessary it is to audio reproduction. Everything else, including horns, now sounds as if it is playing in slow motion. Not having to start and stop those heavy cones really does make a drastic difference. Listening to other very fine conventional speakers makes me feel like something is missing; because it is. It’s like driving your first ultra-high-performance sports car. I laughed out loud the first time I drove a Ferrari. The mylar panels are so responsive it’s ridiculous. And no I did not get that from the Podium panels I reviewed previously. They were not ESL’s. But what about that cone woofer below those mylar panels? Can it keep up with the quick panels? More on that coming up.

By the way, we’ve established that the ESL’s are super fast, but what about the amp driving them? Recall that the super fast Luminous had a slew rate of 250 vps compared to the big $25,000 Krell’s of 100 vps . I looked at the Roger’s spec for his amp: Slew rate: 500 vps. Five hundred! Lorda mighty! Is there another amp anywhere with that spec?

But speed alone does not make great sound. While the panels are tall and semi-transparent, the 10b’s are sonically totally transparent. There is just no sense of music being emitted by a speaker. Pffft! Disappeared! In the past, my ears have been assaulted by the beaminess of some panel and ESL speakers. It sometimes sounded like I was listening to razor blades. Some regular speakers do that, too. Ugly, very ugly. There was never a hint of glare, shouting, beaming or anything non-musical from the low mids up. But what about that bass cabinet? We’re getting there.

While there was complete macro transparency as relates to the overall lack of perceived sound emitters in the room, the macro transparency – that space between, around and during the notes – was as good as if not superior to anything ever in my system. Huh-oh. We’re starting to hear a lot of superlatives here and words like “best ever”. Is Stereomojo selling out?

Well just hold on. We haven’t talked about vocals yet. For me, if a speaker can’t do guys and chicks well, it’s worthless no matter how fast or otherwise great it is. The Stereomojo disk as you can see is replete with several vocal tracks. You’re not going to like this. Male and female vocals were so pure and uncolored I had to start digging out older LP’s and CD’s I hadn’t listened to in years. And for me that almost never happens.





Sibilance is that nasty hissing, smearing sound you sometimes hear when a singer, usually female, sings and “S”. It is usually not on the recording as such, but a artifact of

playback. And it is not confined to digital, LP’s can do it, too. In an LP it is a misalignment issue or bad tracking for one reason or another. It is related to timing. Same thing with digital. The sound is being smeared. A source, an amp or a speaker can cause it. Cables too to a lesser extent. Here’s the thing. With Roger’s babies…no sibilance. Zero. Sometimes it takes a while to notice something is not there and since the Sanders was causing sensory overload anyway, it took some time to realize what was not happening.

I pulled out my sibilance torture track; “So Nice” by Stacy Kent from the “Publisher’s Award” winning “Best Audiophile Voices” CD. There’s a link to my review of it at the end of this one – if we ever get there. Just the title can sound like “S-s-s-s-s-s-o Nic-c-c-c-c-c-c-c-c-e”. I have heard this played back so badly that it hurt like being hung upside down naked and having your testicles tapped by a silver spoon. I know. Somehow the “silver spoon” part of that is the worst. Here’s an “inside the recording studio” secret; for years engineers have been using a device called a “De Esser”. Here are pics of a software plugin and a hardware rackmount I own;






A De Esser is really just a compressor tuned to specific frequencies to help reduce sibilance. The problem is, you just can’t take it out without compromising the sound quality. In addition to the threshold parameter used to set the processing level, there is a frequency controller for setting the center frequency of the process. Processing therefore compresses the entire selected range, not just the sibilant or S sounds. So you get things like lisping and a nasal-sounding vocal. And compression that kills dynamics.






What I heard was Stacey caressing her S's a little too much and too long and a little peakiness in the recording in the range around 3-4K. But it sounded pretty natural; no silver spoons in sight. No smearing. And that was the case throughout the frequency range; simply the cleanest, smoothest, unsmeared audio imaginable.



I have had the privilege of evaluating several speakers whose forte was dynamic range - the ability to accurately and fully reproduce the sonic distance between the loudest and softest sounds in a recording. Many if not most speakers constrict dynamic range. Speakers like the ATC 150’s I reviewed do dynamics range superbly. They better – they are home versions of studio monitors used to record and mix many Grammy winning recordings. The powered Salagars were also very adept as well as the Nola’s and a few others. Dynamics have always been a weakness of ESL’s because they just don’t play very loud. The Sanders’ do. I measured 100 db playback without them breaking a sweat. No breakup, no bottoming out, no arcing and no shards of mylar panels exploding in the room. Just pure, clean, undistorted music. It’s a beautiful thing. When the wide dynamics are combined with the speed, things like guitars, drums, brass and pianos are taken to a higher level. Yet another past limitation of ESL’s bites the dust.

I guess I might as well go ahead and admit it; the Sander’s 10b system has the best mid and upper ranges I have had the privilege of hearing in my home. I keep saying “in my home” because hearing anything outside of the system and room I know most intimately is not as accurate. However, I can honestly say that what I heard via this system at least competes with anything I have ever heard at any show at any price. I did not say these are better, as good as, or “the best”. There are systems and speakers that do more in the realm of “hifi-ness”, but among the many great audio experiences I have enjoyed I just cannot recall a more musically satisfying experience than the Sanders system in Casa Mojo.



I had to laugh when I asked Roger about the sweet spot – or lack of it – in electrostats. Being the up front, honest and transparent guy that I am, I told Roger that the main reason I’d never buy ‘stats is because my wife and I like to listen to music together. Being the male chauvinist pig that I am, I hog the center position while she is relegated to just-right-of-center, so we need a wide sweet spot. And there are speakers that where she sits sounds every bit as good as dead center. Sanders would tell me those are bad speakers. He also told me the solution with his speakers would be to place Linda in a chair directly BEHIND me to listen to music! Yeah right. So imagine my surprise when a few minutes into her first listen I ask her how it sounds over there she says, “Not bad. Pretty good actually.” The first thing Linda listens for is left to right balance; is the singer in the middle and the band behind and spread left to right. I thought for sure we say, “I’m only hearing the right speaker”, something that is not unusual. But she didn’t. Something was wrong. Now, in my own defense and being the loving husband that I am, I never truly hog the center chair but always invite her to switch. When I sat in her chair, indeed I was hearing a stereo image and a rather well proportioned soundstage. There was a strong sense of phasiness and the overall presentation was a bit fuzzier, but it was pretty listenable, which was a big surprise.

One of my best and oldest friends was in town and came over. I had helped him pick out his current system comprised of Revel speakers and Mark Levinson electronics. The choices had to do more with what brands the local dealer had to offer more than anything else, but he has a very fine sounding system; one which he has upgraded over a period of three decades. He also happens to have great ears. Sitting in the sweet spot, he told me that what he was hearing was far superior to what he had at home. When he scooted over, he said that there was a drop off in the high and low end and detail became more obscure, but he thought it still sounded as if he were listening to live music off to the side and not in a center section. There was still a strong left/right/front/rear presentation.

While I cannot declare that the ESL sweet spot challenge had been overcome, it has certainly come a long way under the Sanders regime.



So we have established that the Sanders 10b’s are world class from the midrange up. The vast majority of music lives there so we can all just go home now, right? Not so fast. Music needs a foundation of low frequencies upon which to build and Sanders claims that these go down to 20 Hz. There are not many speakers that come anywhere near to that spec and even if they do they are in a much higher price league. But producing low bass is not the biggest challenge hybrid ESL designers have to contend with. No. Matching the ultra speed and dynamics of the panels with a standard magnetic (slower) cone driver is the problem. Like a bad toupee, the seam between the panel and the cone is the Achilles heel of hybrid ESL’s.

If the continuity between the “cone” bass and the ESL panels is such an issue, why not just make a speaker that goes down to 20Hz using all ESL panels? Rogers responds in his inimitable factual, no-nonsense style; “I have built many full-range, crossoverless ESL's. They are much easier and less costly to build that a transmission line hybrid. But you can't beat the laws of physics. A full-range ESL is a severely compromised speaker that cannot produce deep bass or high output. Also, the bass quality is truly awful (flabby, boomy, and wimpy) due to the high "Q" behavior of the diaphragm around its fundamental resonance. An ESL is a drum. That's right -- its tensioned diaphragm is exactly like a drum. And if you operate the ESL near the drum's resonance, it will have massive amounts of overshoot and ringing that totally ruins the sound quality. Also, the magnitude of the resonant peak typically is 16 dB! A full-range ESL will act like an extremely poorly controlled and heavy woofer that will not stop moving when it is supposed to (think bass drum).

Bass needs to be clean, tight, and highly damped. In other words, a good woofer system will have very low "Q." Only two types of woofers systems offer this quality -- horns and transmission lines. Bass horns must be huge for good performance, so they are not a practical way to build woofer systems for most homes. Therefore, I use transmission lines. The trick is to get a conventional woofer to integrate well with an ESL, which has an extremely low "Q" (when operated above its fundamental resonance).

It has taken me 17 years to solve this problem. But I think you will agree that the Model 10b is very well integrated and sounds like a single speaker is reproducing the music. Its bass performance is vastly superior to a full-range ESL”.



Perhaps the folks at Soundlab would dispute Roger's claims since they make several all electrostat (non-hybrid) models that they say go down to the twenties. Their top model, the Majestic, is said to bottom out at 24 Hz without using cone drivers. It retails for $32,000/pair and I have heard them several times at various shows in demos of IsoMike recordings by Ray Kimber. Ray uses 12 of the 200 lb., 8 1/2 foot tall monsters driven by a truckload of Pass amps. The total system was said to cost close to half-a-million bucks. I never heard any flabbiness or drum effect. The sound was pretty spectacular as one would expect for half-a-mil.

A closer comparison would be the Millinium 2 model at $12,000/pair that claim a low limit of 30 Hz. I have not heard these but certainly would like to. These do feature variable bass and mids like the Sanders but also ad variable highs. No remote though, so you can't make the changes while listening. There is also no bass amp included nor a preamp function with remote volume control like the Sanders. But, thier existance would seem to contradict his belief that a true full-range ELS is "severely compromised". According to Soundlab, they have patented a principle called "Distributed Bass Resonance" that virtually eliminates the membrane "drum-head" resonance and dipole energy cancellation.


Martin Logan also makes a full-range ESL. Roger’s hybrid is spec’d at 20 Hz for a bottom limit. The CLX? 56. Huge difference. At $20,000, they cost more and do not include a 330 wpc bass amp, a preamp with remote and the ability to adjust mids and lows from your chair. They are also much bigger.


As you can tell, Roger is very confident in his product. Let’s see if that conviction is deserved or if his self-assuredness is more fiction than fact.



So far I have attacked the ESL’s main weaknesses. But there was one more big one looming and it may be the most critical; the seam between the ESL panels and the magnetic cone bass. Roger will tell you that physics dictate that they cannot absolutely sound identical. Therefore, the challenge is to make the transition as unnoticeable as possible. The outcome of this review for me and for many others would hinge on how well Roger was able to suture the two divergences together. Not plastic surgery per se, but close – the panels are made of mylar…

I ran a couple of cascading frequency response tests but that doesn’t tell me too much other than the linearity of a single sine wave. For me, the true test would be a solo instrument that is difficult to reproduce in the first place and which widely spans the frequency range in the second. Third, it is one with which I am very intimately acquainted. If you’ve been around Stereomojo much, you know that I started playing piano at age 2 and began formal study at age five which continued until I got my degree in music, followed by another 20 or so years in the music profession. I know what piano is supposed to sound like. Especially the recordings I made over the years. Playing these would put the 10b’s under a scanning electron microscope.

The 10b’s cross over from ESL panel to the bass cabinets at a rather high 300 Hz. That corresponds roughly to D above Middle C on the piano keyboard or almost smack dab in the middle. There is no place to hide. Needless to say, that is the area on which I concentrated. I should mention that the included preamp/crossover/bass amplifier is analog. It uses Linquitz/Reilly filters with 24 dB/octave slopes. Roger told me that in his opinion the analog route is not the best way. He says his digital crossover is even better, “But my customers sometimes cringe when I even mention the word “digital”, so I make the analog version standard. But I can give them a better digital model”.


I continued the bombardment with other favorite piano solo recordings such as “Nojima Plays Liszt” (Reference Recording #25). As a recluse, Nojima makes Howard Hughes look like Howard Stern. This guy could have taught Bobby Fisher how to hide out. His playing is so precise he approaches an almost machine perfection, yet he has the romance and warmth of the old schoolers like Rubinstein and Horowitz. Recorded in 1987 in HDCD at the Oxnard, CA Civic Auditorium, it still stands out as one of the best piano recordings ever. Long out of print, Reference Recordings brought it back in 2006 and is among its top sellers. Of particular interest is the famous Mephisto Waltz – torturous and diabolical to play and to hear, it was one of my favorites to knock around. I wish I could still play the thing.

The London (414 600-2) recording of Vladimir Ashkenazy playing Chopin waltzes is dear to me since I have performed most of these waltzes and I like his balanced of technique and passion so critical in their interpretation.

Peter McGrath is one of the world’s premiere recording engineers who now happens to be the front man for Wilson speakers. I’ve known him years prior since he used to own a high-end store in Florida I visited frequently. I think it was the Montreal audio show at which he unveiled a live recording he had recently made in Miami of a Spanish pianist named Pietro De Maria. He played it back (over Wilson speakers of course) in hi-rez 24bit. In terms of raw virtuosity, power and expression, the playing was stunning and the recording was superb.

As I listened, his style was such that I felt as if I were listening not to him in a formal concert, but to the composers themselves just sitting down casually to toss out a couple of their most beloved compositions for a few friends. The composers were very diverse; Scarlatti, Schubert, Liszt, Mozart and Chopin. Of course, I had to have it. It is on the VAI label (VAIA 1204). This recording is not only great for evaluating how well a system plays back piano but also how well it captures “feelings” and the other intangible “drops of emotion” that Emmanuel Kant thought made up the true path to reason in his “Critique of Pure Reason”. What I mean to say is, this recording will reveal weaknesses in systems if you know what to listen for.

I listened to many, many solo piano recordings via CD, SACD and vinyl while concentrating on the continuity of that splice between 300 cycles and lower vs. 300 cycles and higher. How did they compare in terms of speed, texture, sonority, timbre and every other sonic quality I could think of?

But that was not punishment enough. I went nuclear and pulled out the pipe organs and listened carefully again. All this was not in one sitting, rather over a period of two weeks; a steady diet of the most arduous recordings in existence. What this verdict? Was there a seam, split, disparity or discrepancy between the top and bottom?

Let me phrase this carefully and succinctly; if I put the crossover point under an sonic microscope and focused on it, yes – a small difference in character can be detected. Of course, that can and often does happen in conventional speakers as well. But – under normal listening conditions, the linearity from top to bottom is outstanding and absolutely not a detriment to an extremely high level of musical enjoyment. In short, it didn’t bother me a bit. In fact, the bass in terms of speed, solidity, cleanness, dynamics and detail were nothing short of exemplary. These babies go low. Can I confirm an in-room response down to 20 Hz? No. But I could not care less what the actual number is. At no time did a feel a need for more or better bass. Now there were certain times when a particular recording could use a bit more oomph, but guess what? I just took the remote and dialed up a db or two more via the crossover amp! I loved that feature, and it’s the same for the midrange as well. Now, I wish it were possible to do the same with the top end, but that is not an option with the system I had. And turning UP the bass and mids is not the same as turning down the highs.

So here it is friends, something I really loathe to say, but in this case it is unavoidable: the Sanders 10b speaker and amplifier system is THEE best system I have yet to have in my home. This system not only pressed all my musical buttons, it just flat demolished them. Am I saying it is the best in the world? No. I have not heard every speaker in the world and neither has anyone else. So when you see a critic say something like “The best on the planet”, he is lying. Unless, of course, he has actually heard every speaker on the planet. Even if he has, it’s pretty obvious that his “best” might sound like crap in another room or system. Or even to someone else’s ears. Don’t get me started…
The fact is, your buttons might be very different than mine. All we can do is give you our opinions. It’s up to you to take it from there.

There is so much more to say about these speakers and the electronics that come with them as well as the optional ESL amp I used, but this is much too long already. Let’s go to the bottom line.



Recommendations don't get more specific than this, I think. The Sanders 10B system has the ability to play music in a way that is not often heard at any price and never to my knowledge at $12,999. In addition, they are the fullest of full range, able to play in the subsonics (some subwoofers do not go as low) which is rarely if ever found at this price point. They will rattle pictures on the wall and flap your pants if you so desire and want to go deaf. You can feel the bass and it even vibrated the chair at times. Hmm…that could be a real selling point to many wives come to think of it. You also have to factor in that with the speakers you get a single input preamp and a universal remote to control it. The backlit remote also allows you to adjust the bass and mids levels from your seat so you can hear the changes. What’s more is that a dedicated bass amplifier is also included that puts out 330 watts per channel at a very high quality. You can add your own amp for the mids on up or buy Rodger’s model that is designed specifically for the unique demands of ESL’s. Roger sells direct so there is no middleman to pay. He is supremely confident in his product to the extent that he offers a 30 Day in-home risk free trial as well as an unheard of LIFETIME TRANSFERABLE WARRANTY. Do you now anyone else who does that? And how much does that add to the value quotient.

Is this system for everyone? No. The manual says that you do not have to place them out in the room – you can place them against any wall side or back. Mine were about 9 feet from the back wall and we could hear that much depth. I think placing them against a back wall would diminish that, but I didn’t design them or try them that way. Placing them close to a sidewall is fine – a real no-no for conventional speakers. They are designed to have a hard reflecting wall behind them. I did. The sweet spot becomes smaller if the back wall is damped. Remember the sound comes out the back as much as the front of the panels. They must be equidistant from you and pointed right at you.

And Roger confessed another factor. “Wives are my biggest problem”, he grimaced. “I don’t know how many times the husband wanted to buy them and the wife said “no way”. Thank God for Linda. These did not bother her at all, but she is used to having speakers out in the room. And they are tall. You just can’t hide ‘em.

If your current amplifier is low output tube or solid state that lacks a very hefty gain output – not just watts – you may have to upgrade it. ESL’s use voltage, not watts. I wanted to try a higher output tube amp with them but all I had at the times was a few SET’s. And ESL’s do NOT like “digital” or Class D or T amps. If you have one, it may well blow up with these. It should be noted that both Sanders amps ran surprisingly cool even when pushed hard.

The fact that both speakers need to be plugged into AC may be factor for you. Since they are also bi-amped, you could have two sets of speaker wires as well as AC cords for each speaker. I always left them on – they draw very little current – but you may not want to. Same with the controller/amp. I left it on. Each time you turn it off it goes back to zero volume and defined levels for the mids and bass. You’d have to readjust them every time if you turn it off, though there are big number LED’s to make that quick and easy from your chair.

There is some assembly required. you do not take thse out of the box, connect a wire and juice them up. If you are disabled or otherwise challenged, that may be an issue, but the assembly is very well documented and if I can do, so can you.

Lastly, there is that sweet spot issue. It’s not nearly as bad as earlier generations and may be perfectly acceptable to those who mainly listen solo or whose partner is not too particular.

So. A very positive review. But would I actually buy these speakers myself? If I were not a reviewer, these would never have gone back to Roger. But because of their unique characteristics in amplifier demands and the default bi-amp set-up, they would just not be versatile enough for the breadth of gear with which I have to work. Sometimes practical trumps preference. I did want to buy the ESL amp, but Roger informed me that he has a new groundbreaking amp ready to go that has a linear power supply. Frankly, after listening to his description and knowing his philosophy and demand for perfection, I paid for it sight unseen and totally unheard. And yes, we will have the world’s first review of it, too.

If you are in the least bit interesting in pursuing these speakers or amplifiers, or even if you just want to learn more about audio, you should visit Roger’s website. There is more information there than we could ever include here. Roger also tells me that he will soon have a smaller version of the Model 10b called the Model 11a. It will have the same type of electronic crossover and bass amp that he sells with the 10b. However, its price will be considerably less at $9,995.



Because of the extraordinary value-to-performance ratio,the Sanders 10b Speaker System was given our

Speaker of the Year Award for 2008. Congratulations to Roger Sanders

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