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Sanders Sound Model 10 Electrostat Speaker Review

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Sanders Sound Model 10 Electrostat Speaker

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 driven by magnetic forces; 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 White Paper.  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 similarly ideally suited; it differs from the Magtech only in not having a regulated power supply.  Read the ESL amp White Paper here.  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 180o out of phase; 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 at lower frequencies; 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.

13 Responses to Sanders Sound Model 10 Electrostat Speaker Review

  1. Dean K says:

    I have owned the 10c speakers for a couple of years and continue to enjoy them. I obtained a replacement audio output board for the dcx 2496 that simplifies the circuit, uses better opamps, and also uses a remote control to vary gain…it can be used as a system volume control. A board is also available to replace the digital input / clock circuit. All I can tell you is that I wish Roger would offer this as part of his 10c system, it elevates the transparency, removes grundge, and just makes the speakers better. Contact Ward Maas at for more info.

    • Mark Maloof says:

      Roger does not believe op amps make a difference (he used very inexpensive ones in the Innersound crossover amp, and told a friend of mine who is an op amp guru that “they all sound the same”). I replaced five of the op amps at my friends advice and it made a TREMENDOUS difference. I’m very much a fan of science and like much about objectiveness, but while I was once a “doubter” of some of the tweak nature of high end audio, I’ve come to find over time that numerous things I used to mock I could hear differences in if I gave it a chance and a bit of an open mind. Yes, there is snake oil crap, but there are other things that I have noticed making an improvement (like cables, ha ha ha! Yeah, I used to be in the “all sound the same unless poorly designed” camp, and mocked the cable swapping crowd. Then I stopped mocking and started listening more….)

      • Mark Maloof says:

        The op amps I was talking about above (that I replaced) are in the Innersound (now Sanders Sound) crossover amp, not a Behringer unit, just to clarify. Have heard the DCX2496 at shows in Roger’s room, but have not tried it yet in my system).

  2. vdorta says:

    Thanks for both reviewing a great speaker and interviewing one of the great pioneers in high-end audio. I would like to listen to a pair of Model 10s with a DEQX HDP-4 instead of the Behringer. The DEQX would serve as digital crossover with very steep filters (maybe lowering the crossover point below 172Hz significantly), it would correct both speaker and room, and even seamlessly integrate a pair of subwoofers at any reasonable frequency. Let me just dream.

  3. Rick Tomaszewicz says:

    Glad someone in audio review tells it like it is WRT what live music actually sounds like. Having had subscription series to symphony orchestras and listened to more live jazz than most people, I can tell you that imaging is an pot of gold at the end of the audiophile rainbow. Now, that’s not to say that pinpoint imaging doesn’t have its own visceral enticements, but it’s not what real live music sounds like. So, perhaps we need to abandon the notion that audiophiles must pursue “the closest thing to live”. Maybe we should recognize different tastes and expectations for different audiophiles and leave it at that. Personally, I’ll spend my extra money on live music and more vinyl rather than more exotic gear.

  4. Chris B says:

    Lots of active crossover options listed here (both analog and digital)

    Has anyone tried a 48dB/oct analog crossover with the model 10s such as the Marchand XM44 and compared with the Behringer?

    • Phil N says:

      Chris B
      48dB/oct is the standard setting. Roger crosses at 172hz at 48 on both sides.
      I am test driving a Deqx Premate at the moment, with my 10c s. I am told a HDP4 [ 3 way] has a tweeter x-over that does not go low enough, so you are throwing away a crossover. Save money and buy the 2 way Premate. I have yet to ponder that info. and purchase.

      • Phil N says:

        6 weeks later…I have bought the HDP4. For $500 more, you get better transparency and thus imaging. This must be the linear power supply. I saw inside both machines. Anyhow, I thought it no contest in the end. This is so far ahead of my Behringer set up of dcx2496, deq2496 and src2496. I am a happy chappy.

        • Phil N says:

          Oh yes…the included asynchronous usb input is truly excellent. I surpasses my Audio-Gd DI V3. I think it injects I2S directly into the digital receiver. I play [a] from a netbook via usb and JRiver,[b] Squeezebox Touch with EDO mod to usb from a SD card [c] cd from Oppo 95 [d] vinyl via SOTA/SME and AQVOX balanced phono stage.

    • Mark Maloof says:

      Roger once told me that in order to get the crossover slope that is used in this instance with these speakers, it can only be done in the digital realm to get it low enough. The crossover point in the bass panel amp on my Innersound Eros III amp (his speaker company before Sanders sound, but it’s basically the same speaker), is 310 HZ, higher than what can be done with the DC2496. So that would rule out any analog crossover like the Marchand.

      • Mark Maloof says:

        Do you have an active crossover amp, or one of the rare passive crossover Eros models? I have the crossover amp (actually, it’s an Innersound Kaya amp, better transformer and 330 watts at 8 ohms). I have a friend who is an op amp expert, and under his recommendation, I replaced five cheap op amps better (and much more expensive) ones and it made a notable improvement to the sound. I had thought about trying the DCX2496, but afraid the cheap nature of it might ruin the sound (plus I listen to tons of vinyl, have over 3000 lps, so do prefer the idea of not “digitizing” the signal). There are the replacement boards by Pilgham audio mentioned in the first post, so maybe I should pick up a DCX2496 just to try and see if the lower crossover point wins out over my “hotrodded” Innersound crossover amp. If not, I can return the unit. If it shows promise over my crossover amp, then try the upgraded boards mentioned. But….your mention of the Marchand intrigues me. The price is a bit steep (compared to the DCX2496), and I don’t know if Marchand has a return policy, but I do see they sell a board unit only of the crossover which of course is much cheaper. Hmmmm…wonder if it could be installed in my Innersound crossover amp?

  5. Chris B says:

    I purchased both a Behringer DCX2496 and a Marchand XM44 to try with my Eros MKIII.5. Both tuned to 48dB/oct at 172Hz with the equalization as specified by Roger in his DCX setup manual. They both made the lower midrange much more transparent. There was a “hollow sounding” coloration with the stock crossover. However…. The Behringer obscures microdetail which the Innersound are known for. I preferred the stock crossover for its natural detailed sound despite the lower midrange coloration. Then came the Marchand XM44 with the same tuning as the DCX. The stock Marchand was better than the Behringer for sure but i still felt it was slightly “hifi” sounding. After lots of research, I ordered some dual OPA627 and DEXA discrete opamps from Partsconnexion. I put a pair of DEXA in the input section. I ended up using the OPA627s in the high pass section only since the stock opamps are a little punchier in the low pass. Bingo! This combinations sounds amazing! The lower midrange is seamless now, the bass dynamics and articulation much better, the microdetail is still there, and as an added bonus the high frequencies sound much more extended. Somehow the stock crossover was making the Eros sound muffled. These were always awesome speakers, and now sound even better.

  6. Dennis says:

    I have the new 10Ds and I have a modded behringer done by Audiosmiles in the UK and it is truly amazing.

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