Sanders Sound Model 10 Electrostat Speaker Review--站点名称
Sanders Sound Model 10 Electrostat S
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I first heard Inner Sound electrostatic speakers, the predecessors to Sanders Sound speakers, nearly a decade ago at an audio show.& I was immediately impressed and each successive year at Rocky Mountain Audio Fest I made a point of listening to them, often bringing friends to do the same.& At last year’s RMAF I spent hours in the Sanders Sound room, and asked designer and proprietor Roger Sanders whether I could review the speakers.& He graciously agreed.
Background
I recently conducted&, to which I direct those readers who are interested in Roger’s views, philosophies, and approaches to audio.& To avoid redundancy, here I will touch on just a few main points.
Roger has been designing and building electrostatic speakers for forty-plus years, and published his first article on electrostats in Speaker Builder magazine in 1974.& This and his subsequent articles can be found on Roger’s homepage& under “Audio Related Articles.”& Roger favors electrostats for their speed and transparency, but recognized early on that the panels could not “move enough air” to provide realistic bass response.& Accordingly, his speakers are a hybrid design, in which the electrostat panel is paired with a cone woofer, about which I will have much more to say later.& In 1980, Roger described a curved electrostat panel, but immediately rejected it as being inferior to flat panels.& Coincidentally — or perhaps not — in 1981 a new company came onto the scene, featuring an electrostat with a curved panel.& To this day, that company uses curved panels in their entire product line.& In 1993, Roger’s “Electrostatic Loudspeaker Design Cookbook” was published, so it can accurately be said that Roger wrote the book on electrostats.& Since that time he has continued to refine the design, the culmination of which is the subject of this review, the Sanders Sound Model 10.
As mentioned, Roger’s designs were originally sold under the name “Innersound.”& Roger left Innersound in 2004, and started Sanders Sound Systems, LLC &in 2007. &Innersound went out of business in 2008 but out of concern for his previous Innersound customers, he continues to provide service and support for Innersound products.& All Sanders Sound products are designed and manufactured in Colorado, USA.
Intelligent Design
For this review, I anticipated receiving one or two large crates, and assumed I would need help from one or more friends to get the speakers into my listening room.& Unbeknownst to me, Roger has devised a clever means of simplifying shipping.& Instead of a large crate, what I received were two boxes each with a woofer cabinet, one flat box, and two long tubular containers.& To assemble the speakers, Roger provides instructions that are truly the epitome of simplicity.& First, one removes the woofer cabinets from their cartons.& These are the heaviest of the cartons, but are easily managed.& Following Roger’s instructions, one positions the carton so as to not damage the driver, then removes the carton from the woofer cabinet rather than&vice versa, thus avoiding any heavy lifting.
Second, one removes from the tubular container, four vertical supports.& One support attaches to the left front of the woofer cabinet, the other to the right front.& Each support is held in place with four supplied screws.& The supports have Velcro on them, which is key to the simplicity of the rest of the assembly.
The flat box contains the left and right electrostat panels.& These, too, have Velcro on their left and right sides both front and back, for reasons that will become clear at the later steps, so one simply aligns them with the top of the supports, and applies some mild pressure.& The instructions make clear that it is not a problem if the panels d simply detach them from the support, and re-align them.
The next step is to snap together the electrical connector, one per speaker, one half of which is on the panel, the other on the woofer cabinet.& In the penultimate step, one puts on the woofer grills.& These also have Velcro on them, both front and back, so one aligns them beneath the electrostat panel, and applies gentle pressure.
The last step is to add the decorative vertical slats, which match the woofer cabinets.& These too — you guessed it — have Velcro, and are attached to the Velcro on the outer surface of the woofer grills and the outer surface of the electrostat panel.
As is the case for all electrostats, the Model 10’s must be plugged into a wall socket, which allows a static charge, thus the name, electroSTAT, to be placed on the membrane.
The first panel took perhaps fifteen minutes to assemble, t assembly is that easy.& Moreover, should a panel or woofer fail, both have life time warranties, and failures are extremely rare, one need not replace the entire speaker.& The design of these speakers is not smart.& It is&very&smart.
Power and Connections
The Models 10’s are a two-way design and because they are actively crossed-over (more on this below), they require four channels of amplification in the typical form of two stereo amplifiers, but one could use four monoblocks, or one stereo and two monoblocks.& Included in the purchase price is a Sanders Sound stereo Magtech amplifier.& This amplifier has enormous power and a regulated power supply, and was specifically designed to meet the needs of what Roger calls “magnetic speakers,” though it is equally suited for use with the electrostat panel.& By “magnetic speakers,” Roger means any speaker whose moving surface is drive these include drivers with voice coils like cones and domes, as well as ribbon, planar magnetic, and plasma speakers. &In contrast, electrostatic speakers are driven by high voltage force fields, not by magnetism.& The user must provide an additional amplifier for the electrostatic& panels.
Electrostats are actually large capacitors, and thus their impedance drops to very low levels — close to 1 Ohm — at high frequencies.& The chosen amplifier must be able to cope with this low impedance, and have enough power to not clip on transients.& Regarding the issue of how much power a speaker needs, I recommend Roger’s&.& As I mentioned, the Magtech fills the bill nicely, and does so at a price of $5,500 for the stereo version, which is a bargain.& For those customers looking to save a little money, Roger’s ESL amp at $4,500 is simi it differs from the Magtech only in not having a regulated power supply. &Read the ESL amp White Paper&. &For most of the review I used a Magtech on the woofer, and an ESL on the panel.
The Behringer crossover
The active crossover is a Behringer Ultra-Drive Pro DCX2496, which is included in the price and comes fully programmed. &Roger makes a number of modifications to the Behringer. &On the aesthetic side, he machines off its rack-mount “ears,” strips off the labels and white lettering from its lid, and powder-coats it black. &These changes make it look less like “pro-gear,” and more like high-end audio equipment. &Internally, some changes are made to improve reliability. &Roger adds feet, reassembles the unit using stainless steel hardware, and does burn-in and test processes over a two week period of time. &Roger then provides a lifetime warranty for the modified Behringer, as he does the rest of the speaker system.
Like all active crossovers, the Behringer is connected between the preamp and the amplifiers. &One thus needs one set of interconnects between the preamp and the Behringer, two sets of interconnects between the Behringer and amplifiers, and of course two sets of speaker wires between the amplifiers and speakers. &The Behringer uses XLR inputs and outputs, but can be operated in either balanced or unbalanced mode. &For customers who have only RCA interconnects, Roger can provide XLR/RCA adaptors &at extremely reasonable prices. &He also can provide, again at extremely reasonable prices, interconnects and speaker wire that have the correct electrical properties. &While more exotic cables might provide better, or at least, different sonic properties, I used Roger’s cables with superb results.
The Behringer serves two functions. &First, it is an active cross-over, splitting the signal between the electrostat panel and the woofer. &Second, it provides a shelf, which requires some explanation.
Electrostatic panels are by their very nature, dipoles, and put out as much energy to the front as to the back. &Because the Model 10’s have no cabinet, the front-waves and back-waves can and do interact. &At higher frequencies — which have smaller wavelengths — this is not a problem, because the panel itself effectively separates the front- and back-waves. &However, at lower frequencies, in which the wavelengths becomes large in relation to the panel width, the front- and back-waves “wrap around” the panel, and interact with one another. &In a dipole the front- and back-waves are 180 thus when they interact, they cancel one another (“destructive interference”), resulting in attenuation of the signal. &Because of the width of the Model 10’s electrostat panel, the attenuation becomes significant at approximately 2 kHz, and the attenuation increases as the frequency gets lower. &The Behringer provides a shelf function which is in essence, an equalization. &That is, a progressive “boost” is provided below 2 kHz such that, when combined with the natural dipole cancellation and with the cross-over, a flat frequency response is obtained. &The Behringer also provides a small boost below 35 Hz, to compensate for the decreased air resistance which occurs
this phenomenon is known as “radiation resistance losses”. &This pushes the low-frequency response to a lower roll-off, but does so while maintaining a flat frequency. &This is in contrast to the more common practice of providing a boost at a particular frequency, the goal of which is to provide the illusion of more bass.
Because the Behringer is a complex device with numerous functions, its user’s manual is extensive, and can be somewhat daunting.& For those owners who do not have the time, patience, or inclination to read it, there is a single page in Roger’s speakers’ manual that gives simple, quick, and easy instructions that make it a snap to connect the crossover and make adjustments.
This seems like a good spot for a slight digression on active crossovers.& I should first point out that the benefits of active crossovers apply to any speaker with a woofer, not just electrostatic hybrid models.& Woofers are by necessity large, with high mass.& One of the main factors influencing their transient response is not their ability to start but rather, their ability to stop.& Imagine a musical signal with two transients, separated by a very short interval.& In response to the first transient the woofer begins to move but as it moves back it overshoots its mark due to inertia, and is therefore unable to respond to the second transient.& Accordingly, it is important to prevent — or at least, minimize — the overshoot.& Fortunately, there is a straightforward way to do so.
As the woofer moves it generates an electrical signal, termed “back EMF,” which as its name implies, is directed back toward the amplifier.&& The amplifier resists the back EMF, and thus serves as a “brake” for the woofer.& “Damping factor” is a measure of an amplifier’s ability to provide this braking function, and thus its ability to control the woofer.& Damping factor is a function of an amp’s output impedance, which explains why solid state amps typically provide better bass control than do tube amps: In most cases, solid state amps have lower output impedance — and thus higher damping factors — than do most tube amps.
Returning to the benefits of active crossovers:& A typical solid state amplifier might have a damping factor of between 50 and 100.& This is very high and in principle, would provide excellent control of the woofer.& But most speakers have a passive cross-over situated between the amplifier and the woofer so, as Hamlet said, there’s the rub.& The speaker’s back EMF does not “see” the amplifier but rather, it sees the crossover.& An unfortunate consequence of this arrangement is that the damping factor is reduced, usually dramatically.& Instead of the amp’s high damping factor, the woofer sees a damping factor as low as only 2 or 3! &An excellent discussion of this topic may be found here:. So the amplifier’s very high damping factor is metaphorically cut off at the knees.& As a result the woofer is not properly controlled, and we end up with sloppy bass.
The obvious solution to this dilemma is to get the crossover out of the way.& One does this by using an active crossover which inserts in the signal chain&before&the amplifier, rather than after it.& In this situation, when the woofer “looks back” it sees the amplifier and its high damping factor, rather than the lower damping factor of a passive crossover.& An added benefit of an active crossover is that it provides, at a minimum, the ability to optimize the bass volume for the particular room and tastes of the listener.& Though in fairness, a speaker with a passive crossover can be designed so as to provide this as well, though it is less common than with active crossovers.
Spreading the Word — On Dispersion
As noted earlier, the Model 10’s use a flat electrostat panel.& By their nature such panels “beam,” and this has been the subject of considerable controversy.& Studies by Floyd Toole and Sean Olive of Harmon have shown listener’s preference for speakers with an even power response, i.e., an off-axis response which is similar in frequency response to the on-axis response.& But as Roger pointed out to me in one of our many discussions, such studies did not compare speakers with a wide dispersion and even power spectrum, with speakers with narrow dispersion.& A sad fact about which many, if not most audiophiles live in denial, is that the room is one of the most important determinants of the sound that reaches our ear.& I can’t begin to count the number of times a fellow audiophile has told me how great his DAC, or speakers, or preamp, or amp, is, but then explains that I can’t hear this greatness because of his room.& Nor can I count the number of audiophiles who will spend many thousands of dollars on new interconnects, power cords, and even, I kid you not, wall sockets, but will not so much as add some absorption to the first reflection points.& Anyone who doubts the contribution of the room need only listen to a pair of headphones.& Even modestly priced models will provide greater clarity than most audiophiles will ever hear from their mega-buck systems, and the reason for this is simple: Headphones take the room out of the equation.
But for a variety of legitimate reasons, many of us prefer to not listen to headphones, or at least, not exclusively so.& So how can we get around the negative influence of a listening room?& If we’re fortunate, we can have a well-designed and well-treated room.& But such rooms are expensive and even if money were no object, for most it is simply not possible for reasons of domestic tranquility.& So how about if instead, we use speakers that allow us to hear far more of the direct sound, and far less of the indirect, i.e., room-induced sound?& Enter the Sanders Sound Model 10 speakers.& Interested readers are directed to Roger’s “Dispersion White Paper” on his website.
Because the Model 10’s have narrow dispersion, the energy reaching the listener from the walls is greatly attenuated compared to that reaching the listener directly.& A legitimate question, and in fact one I myself asked, relates to the speakers being dipoles: Since as much energy fires out the back — and thus towards the walls — as out the front, wouldn’t this negate the benefits of the narrow dispersion?& The explanation lies in the fact that for optimum performance, the Sounders Sound speakers must be aimed directly at the listener.& Because of this, the rear wave hits the rear or side wall at a sharp angle, from which it is directed at an equivalent angle toward another wall, and so on.& By the time the sound reaches the listener’s ears it is greatly attenuated, and temporally delayed as compared to the direct sound.& Under such circumstances our ear/brain can and does distinguish the direct and reflected sounds as separate and distinct, rather than smearing them as occurs if the reflected sound arrives soon after the direct, as occurs with wide dispersion speakers.
The Set Up
I am fortunate in having a large, 30’ x 22’ x 11’ dedicated listening room, with many absorbers and diffusers. &After some experimentation I ended up with the speakers 118” from the front wall, 66” from the side walls , 139” apart, and 139” from my listening position, wherein each measurement is from the center of the panel.& As I noted earlier, the Models 10’s are designed to be aimed directly at the listener.& Roger devised a simple yet effective trick to achieve this. &Because the panels are reflective to light, one can simply dim the ambient light, hold a flashlight over one’s head and aim it at the speaker.& When the reflection is centered, the speakers are aimed correctly.& I should mention that I could get proper center fill of the sound no matter at what distance I sat, provided of course that the speakers were properly a however, despite their directivity, and despite my room being well treated, I still preferred the sound when I was no farther away from the speakers than they were from one another.& Roger advised me to ensure that both speakers were equidistant from the listener, and to do so within a half inch.& I did as he suggested and indeed, this paid off.& This sort of care in setup probably benefits any speaker, but especially so the Model 10’s, as they are so phase-perfect.
As noted above, for most of the time I used a Sanders Sound Magtech stereo amplifier for the woofers, and a Sanders Sound ESL stereo amplifier for the panels.& I also used the Merrill Audio Veritas monoblock amplifiers,&&by my colleague Ray Seda, and obtained superb results with both amplifiers.& Upstream, I used the Miracle Audio Devinitive linestage and Phonatic phonostage.& The analogue source was a TT Weights Gem turntable with Schick arm and Miyajima Shilabe cartridge. On the digital side I used my AMR DP-777 DAC, fed by my&&music server, running JRiver.& As described above, the active crossover was a Behringer DCX2496.& The Behringer comes pre-set for nominally flat response but because bass is so room-dependent, it is usually necessary to make an adjustment in bass volume, relative to the panels.& Roger’s instructions describe this, and show the user which buttons to push.
In the interest of full disclosure, I have to mention one problem that occurred.& After setting up the speakers, I noted a marked channel imbalance, 4 dB, to be exact.& After systematic swapping of cables and gear, I verified that the problem was with the speakers.& I assumed that one of the electrostat panels was defective, so I contacted Roger.& Roger explained that it was highly unlikely that it was a panel but to make sure, he suggested I swap the left and right panels.& As I described above, this is a very easy procedure.& This did not solve the problem, so Roger said that it was most likely a failure of the power supply, which provides a static charge to the panel.
Roger sent me a new power supply, along with step-by-step instructions as to how to change it.& Unfortunately, this, too, did not solve the problem.& Roger was about to send me a new woofer cabinet when he suddenly realized that there was one other thing that could account for the channel imbalance:& The Models10’s can be used with either 110 or 220 V, and it was possible that one speaker was set for the higher voltage.& He told me what to look at on the back of the speaker and sure enough, one speaker was mis-set.& He told me how to set it for the correct voltage, which took about 30 seconds, and voila, problem solved.& Obviously, we would all prefer that none of our equipment ever fails but alas, things do happen.& The important question then becomes, how do the manufacturers handle the issues?& In this regard, Roger scored an A+.& He stood behind his product, and was prepared to do whatever was necessary to correct the problem.& Moreover, when the problem was identified, he apologized for it, which speaks volumes about his character.& On a more practical note, he told me that this was the first time this had occurred but to prevent a recurrence, their shipping protocols would be altered such that the voltage setting would be checked immediately before the carton was sealed.
At Long Last…the Sound
How many times have each of us read a review in which a traditional speaker was said to have “electrostat-like” speed and/or transparency?& Electrostats have a major advantage over dynamic driver speakers, an advantage based on simple physics.& Specifically, I am referring to mass.& In race cars, a car with less mass will always have the advantage over a heavier car in terms of acceleration, deceleration, and handling.& And so the lower the mass, the more quickly the driver (or panel) can start, stop, and change direction. &The mass of an electrostat panel is far less than that of a cone or dome, and less than even that of a magnetic planar, as the latter has conductive wires attached to the diaphragm.& Moreover, the electrostat panel is powered over its entire area, unlike a cone or dome which is powered only near its apex and perimeter, respectively, where the voice coil attaches.& For cones and domes, not being powered over their entire area leads to irregularities in their movement, sorry if that sounds like a commercial for a laxative, which translates as distortion.& And the electrostat panel has yet another advantage over comes and domes: The stators, which carry the musical signal, are present on both sides of the panel, so the panel is both pushed and pulled, which adds still further control as compared to cones and domes.
The advantages enumerated above are far more than theoretical.& Listening to music – importantly, any type of music – through the Model 10’s revealed unrivaled clarity.& Instruments and voice were portrayed with breathtaking detail in virtually every parameter: tonality, rise time, texture, shading, harmonics, etc.& By comparison, most every other speaker with which I am familiar sounds muted, colored, and sluggish.& The amount of musical information provided by the Models 10’s allows a far greater appreciation of the music and sense of realism, as compared to most other speakers through which so much information is obscured.& A number of years ago, when I was affiliated with another magazine, I wrote an article entitled “Real or Surreal,” in which I spoke of the common practice of speaker manufacturers intentionally boosting certain frequencies, to give the illusion of detail.& Ultimately, such speakers become fatiguing, and lend a sameness to all recordings played through them.& The Model 10’s are th they have a very flat frequency response, and provide gobs of information throughout the entire frequency range. &In point of fact, the Model 10’s are amongst the most evenly balanced speakers I have heard.& They are neither warm, nor harsh.& Instead, they provide an incredibly clear and uncolored window into the music, in which every instrument is heard clearly, cleanly and distinctly.& They allow the listener to hear and comprehend the pace and nuance of the performers, and this is true for all types of music.
From their earliest days (think, Quad 57’s), electrostats have been praised for their transparency and microdynamics, but their limitations were obvious:& an inability to play loudly, concomitantly poor macrodynamics, and limited low frequency extension and “slam.”& When early models were pushed beyond the limits, which was easy to do, they would arc — with catastrophic consequences — or the diaphragm would hit the stators.& To prevent this, protective circuitry was incorporated, which would automatically shut down the speaker.& In addition, electrostat panels were sensitive to humidity, dust and insects.
Over the course of many years of experimentation, Roger overcame each of these limitations.& His panels are virtually indestructible with normal use, are not affected by humidity, and come with a lifetime warranty.& Moreover, they are capable of sustained play at so-called “concert levels.”& But the Models 10’s do more they go from soft to loud in the blink of an eye, and thereby reproduce the music’s energy and dynamics.& One of the tracks on Roger’s demo when played through the Model 10’s, it comes incredibly close to the sound of an actual drummer playing just feet away.& I have played this track for virtually every guest to my listening room and
without exception, they have been stunned by the life-like dynamics, all the more so that this could come from an electrostat.& To my utter amazement, the Model 10’s are every bit as dynamic as my horns, though the Models 10’s do, of course, require a lot more power.
The Top and Bottom Must Meet in the Middle
The Model 10 is a hybrid speaker, in which the lower frequencies are provided by a woofer, rather than by the electrostat panel.& Historically, such designs have suffered from a sonic disconnect, in which the low frequencies appear to “lag,” or not keep up with, the higher frequencies.& In response, some manufacturers produce so-called “full range” electrostats.& I have heard a few different full-range electrostats, including some that are very large and very expensive.& Although they were certainly coherent, to my ears they lacked bass slam, and most were also severely lacking in dynamics.& Though they do not offend, they are, to my ear, boring, as they strip music of its energy and vitality.
Roger believes that the only way to get proper bass is with a hybrid design.& He spent many years designing a woofer system that would have a transient response sufficient to “keep up” with the electrostat panel.& His ultimately chose a transmission line design, details of which can be found in the interview I referenced above, and in his&.& To my ears, and to those of virtually everyone I know who has heard the 10’s, the transition from woofer to electrostat panel is seamless.& I have spent many hours listening to the speakers, and I hear no discontinuity whatsoever.& Moreover, the bass is tight, tuneful, and with plenty of slam.& Bass instruments sound like real instruments, which is not the case with many speakers.& Though the Model 10’s are not as extended, nor quite as tight as the&&I recently reviewed, they never left me wanting for more.
Choose Your Music
High-end audio is replete with speakers that sound their best only with certain types of music.& This is typically because the speakers are bandwidth-limited, and also as such, they are most suitable for chamber music, and the typical “girl with guitar.”& Not so the Model 10’s.& Because they are nearly full-range, falling just a bit shy in the lowest octave, because they are so dynamic, and because they are so lacking in coloration, they are equally adept with any type of music.& Chick with guitar, wailin’ rock, electronica, symphony, or anything in between, the Models 10’s excel.& There is no editorializing, no added warmth or harmonics, and no exaggerated peaks.& Instead, the listener is rewarded with an incredibly accurate reproduct nothing more, and nothing less.& With adequate amplification, no apologies ever have to be made with the Model 10’s.
Take a Seat
As discussed above, the Model 10 speakers have narrow dispersion.& When listened to off-axis, especially in my room which is well-treated with absorbers and diffusors, there is a noticeable drop-off of high frequencies.& I have heard the Model 10’s in the home of Merrill Wettasinghe, the designer and manufacturer of the Veritas amplifiers.& Merrill’s listening room is smaller than my own, and less extensively treated.& In his room, the off-axis roll-off is less pronou not unexpectedly, the roll-off became more pronounced when Merrill added some absorption to the walls. &An important point this demonstrates is that even narrow dispersion speakers send considerable energy off- it is easy to understand why the sonics of wide dispersion speakers are so compromised.
Some audiophiles who have not experienced the Model 10 speakers believe that they must listen with their “head in a vice.”& Let me put this to rest, hopefully once and for all.& All that is required for optimal listening is to sit in a chair, equidistant from the speakers.& And while the Model 10s are more sensitive in this regard than are more traditional wide-dispersion speakers, one should be similarly positioned to obtain optimal results with&any&speaker.
When properly set up, the Model 10’s throw a realistic, deep and layered soundstage.& They did not provide the pinpoint imaging some ot this is typical of dipoles, especially those with large radiating areas.& I am aware that there are those who categorize themselves as “imaging freaks.”& As I’ve discussed on numerous occasions, in my opinion pinpoint imaging does not not once have I left a concert and heard anyone in the audience raving about how tight the images were, and for the life of me I cannot fathom why so much importance is ascribed to this phenomenon.& But of course, “to each his own” applies here, as it does most everywhere.& And while I don’t expect to change anyone’s mind, I would be remiss if I failed to point out that anyone who passes up the Models 10’s because of their lack of pinpoint imaging, is missing out on the remarkable way they reproduce music.& Let me say that again, with feeling:&the way they reproduce music.& ‘nuff said.
Old Habits and Preconceived Notions
The Behringer Ultra-Drive Pro DCX2496 that comes with the Models 10’s, is a digital crossover, and inserts immediately after the preamp.& Thus, analog signals that originate from a DAC or phono stage, or tape player, are sent to the preamp, thence to the Behringer where they are (1) converted to digital by the Behringer’s A-to-D converter, (2) processed in the digital domain, then (3) converted back to analog in the Behringer’s D-to-A converter.& The Behringer retails for about $400, whereas my AMR DP-777 DAC retails for $5,000.& Despite how good the Model 10’s always sounded at shows, it didn’t seem possible that the Behringer wouldn’t seriously degrade the signal from my AMR — a case of preconceived notions running smack in the face of actual experience.& Even worse was the thought of digitizing the signal from my v this heretic act would surely be ruinous.& Earlier versions of the Model 10 used an analog crossover, so when I arranged for the review, I asked Roger if I could try one of those as well, to which he agreed.& The analog crossover was built into his ESL amplifier but as that amplifier has been upgraded, I wanted to use the current-production amplifier, with both the digital and analog crossovers.& Fortunately, the amp section in the older unit can be bypassed, so I was able to use just the crossover.
It should be noted that the comparison wasn’t purely that of analog to digital, as other differences exist between the two crossovers, for reasons I’ll now explain.& The fundamental resonance of the Model 10 electrostat panel is around 86 Hz. &The output from the crossover must be down by at least 48 dB at this frequency to assure that the resonance is not excited. &As Roger explained, “The resonance will degrade the bass frequency response.& The resonance is high Q, which will cause the bass quality to become muddy, loose, flabby, and poorly defined due to a lot of overshoot and ringing. So it is essential to keep the crossover point high enough that the fundamental resonance is not excited.”& For his analog crossover, Roger chose a slope of 24 dB/octave.& All else being equal, a steeper slope is preferable but, in Roger’s words, “making steeper slopes with passive inductors, resistors, and capacitors becomes very difficult because the tolerance of the components is so poor that you can’t get their poles to match precisely enough to work correctly. &After all, most capacitors have a tolerance of +/- 20%, and it is common for large capacitors like those used in speaker crossovers to have tolerances of +/- 50%. &Inductors have only slightly better tolerances.”
To achieve the requirement of the signal being down 48 dB at the resonant frequency using a 24 dB slope, the crossover point had to be at 344 Hz or higher. &Roger chose a crossover point of 350 Hz for his analog crossover.& Unfortunately, this means that the woofer contributes significant energy all the way up to 1,400 Hz, at which frequency its output is down by 48 dB. &Thus, the woofer’s output mixes with that of the electrostatic panel throughout most of the midrange, i.e., 500 Hz to 2 KHz.& This degrades the clarity and detail of the midrange, which is best reproduced solely by the nearly-massless electrostatic panel.
In contrast to analog crossovers, digital crossovers, such as that in the Behringer, come with selectable crossover slopes and filter types.& Roger chose a 48 dB/octave crossover slope, which made “it possible to completely eliminate the contribution of each driver within just one octave of the crossover point, thereby reducing the shared bandwidth to a minimum and greatly reducing the stress on the drivers.”& Using a crossover point of 172 Hz, the output of the panel at its fundamental resonance is down by 48 dB, and the woofer output is down by 48 dB at 344 Hz, thus there is essentially no woofer energy in the midrange.& Of course, to compare apples to apples, we could have re-programmed the Behringer for a 350 Hz crossover, but that was more work than either of us wanted to undertake.
Yet another difference relates to time alignment.& The Behringer, but not the analog crossover, &allows one to delay the early-arriving driver, resulting in perfect time-alignment between the electrostat panel and the woofer.& This, too, is part of the pre-programming Roger provides.
So while the comparison between analog and digital crossovers was far from perfectly controlled, it was nonetheless quite informative.& Upon first listening I preferred
it sounded warmer, and more “musical.”& Over the course of a few days, I realized that in fact the sound was muddier, and more veiled, than when the Behringer was in place.& This was a “teachable moment” because I realized that after so many years of hearing a veiled sound, it had became normal and “comfortable” to me.& In fact, many people have this reaction when first hearing the Model 10’s; the speakers are so incredibly transparent that it seems like something is missing, but that something is coloration and distortion.
But returning to my original concerns of the digital crossover, it was apparent that it was not doing anything terribly wrong.& Whether or not an analogue crossover with 48 dB slopes and a 172 Hz crossover point would sound better than the Behringer, remains an open question.& Mostly to satisfy my curiosity, I am looking into obtaining and testing such a crossover.
But incredibly, with the Behringer in the system, vinyl still sounds like, well, vinyl.& When guests come over I usually begin with digital recordings.& Soon as I switch to vinyl they invariably comment on how much better vinyl is than digital.& I then point out to them that the signal has in fact being digitized.& Not uncommonly, I am greeted with blank stares, and I have to explain — slowly — the precise signal path, and what exactly the Behringer is doing.& The blank stares then change to ones of disbelief.& I confess to getting a perverse thrill out of this.
But again in the interests of full disclosure, some listeners claim to hear “the cheap Opamps” in the Behringer. I don’t know if they are hearing something that really exists, or they are hearing something that they presume must exist.& But truth be told, old habits die hard, and I have not yet completely shaken my own skepticism about the Behringer’s sonics.& I am currently investigating alternatives including some that are digital, and will report my findings in a follow-up article.& But the take home message is that even if the Behringer is degrading the sound, it must be doing so to a rather small degree, as the resulting sound is world-class.
Conclusions
In the opening paragraph I said that at RMAF I had spoken to Roger about obtaining a pair of Model 10’s for review.& That was only a half-truth.& In point of fact, what I told Roger was that I wanted to purchase a pair of Model 10’s, and that I would write a review of them.& So yes, the “review pair” is, in fact, mine.& In the months I have had them, they have re-defined my sense of high-end audio, and brought hour after hour of musical listening pleasure, to both myself and many of my friends and colleagues.& My only regret is not having purchased them years ago.& The Sanders Sound Model 10’s are amongst the finest speakers I have heard, and certainly the best I have owned.& At their price of $14,000 including a stereo amp and active crossover, they are also one of the greatest deals in high-end audio.& They unequivocally earn my highest recommendation.
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