ULTRA AUDIO -- Archived Article

June 1, 2008

Esoteric MG-20 Loudspeakers

Every so often I hear something that changes what I know to be possible. For instance, I vividly remember when I first heard an electric violin. Or a Moog synthesizer playing Bach. A Javanese gamelan. Oscar Peterson’s piano, Jan Garbarek’s saxophone. Even the first time I listened to a really good tube amplifier after decades of allegiance to solid-state gear.

My reaction in such moments is predictable. First, jaw-dropping wonderment: What on earth is this amazing, unique, never-heard-before sound? Second, the inner critic: But do I like it?

That was pretty much the sequence of my experiences on listening to Esoteric’s MG-20. This is not your father’s high-end loudspeaker, and doesn’t sound like it. It’s the latest high-end technology from an audio company that relishes the opportunity to do things in new ways that they believe will get better results than anyone else is getting.

Esoteric’s magnesium driver

I don’t know what the TEAC-Esoteric Company’s formal corporate mission statement is, but if their activities are any indication, it appears to be something like "the tireless, unrelenting development of state-of-the-art audio technology resulting in cost-no-object products as well as more affordable products benefiting from trickle-down technology." Esoteric often succeeds at that mission (their digital playback components being Exhibit A), which boded well for the performance of their new line of loudspeakers, and particularly the object of this review: the two-way, d’Appolito-array, floorstanding MG-20 ($10,500 USD per pair, including bases). There’s also the MG-10, a minimonitor version using the same technology, less one midbass driver ($7500/pair, including bases).

Motoaki Ohmachi, president of TEAC-Esoteric, was behind the project to design these new models. Ohmachi has a long history with TEAC, and is no novice to innovation. He was responsible for developing the TEAC reel-to-reel tape recorders that I fondly remember using at KCUR-FM in Kansas City during my three-year stint as a radio producer in the late 1970s. Esoteric’s new MG speakers continue the tradition of breakthrough technology, primarily in the design of their magnesium midbass drivers and in the use of magnesium for the dome tweeter, which allows the speakers to produce their entire frequency range without changing the color of the sound. Note that these are not the magnesium-alloy drivers that have been around for some time and are widely respected for their speed and detail, a prime example being the 7" driver in the Excel line from SEAS of Norway. Despite its considerable virtues, the SEAS driver sounds "hard" to some listeners and has a significant breakup point slightly above 3000Hz.

Esoteric liked the basic properties of magnesium -- its lightness, rigidity, inherent vibration damping, and lack of internal resonance -- and wanted to build a driver of an alloy whose proportion of magnesium had been increased to 96%. But pure or nearly pure metallic magnesium is terribly difficult to work with -- it has a propensity to burst into flame, for instance. Working closely with a Japanese chemical company, Esoteric developed a thin, two-layer coating (an "organic membrane with ceramic coating," to quote their literature) for their magnesium cone that makes the material practical to use and damps internal vibrations even more than pure magnesium. They also corrugated the cone to further minimize resonances and maximize rigidity.

To find out more about the technology of this driver, I talked with Mark Gurvey, Esoteric’s vice president of sales and marketing for North America. "All paper cones add coloration to the sound, and we wanted the driver to give an acoustically neutral, open experience of the music," he said. "The magnesium cone provides very fast dissipation of resonance and a very stiff cone. This also makes a significant difference in the level of detail that you hear." Gurvey first noticed this with his own pair of MG-10s, when he heard details, such as the pedaling of a piano, that he’d never heard before in recordings.

I was also curious about the role of the driver’s relatively soft surround, which is more flexible than in most drivers that try to recreate highly detailed sound. Gurvey contacted Kazutaka Tsuda at Esoteric in Japan to find out more about this for me. Tsuda e-mailed me that the surround is made of nitrile rubber -- a very flexible synthetic rubber copolymer chosen to give longer excursion to the lightweight 6.5" midbass driver so that it can deliver deeper bass response. It also, in their view, provides the best stability and damping for the driver cone at all temperatures.

Suffice it to say, Esoteric has thought a lot about this driver, and the composition of the cone and surround were just the first steps in that process. They’ve also thought about the piston assembly, designing it to provide more linear movement and kill resonances and vibration. They’ve made the die-cast driver chassis with antiresonant materials, not just aluminum. Even the construction of the ferrite magnet is intended to maximize dynamic range and lower distortion.

But wait, there’s more!

As interesting as it is, though, the main driver is only part of this speaker’s story. Perhaps the most striking thing about the MG-20 is its size. At about 42" tall by only 8.5" wide and 11" deep, it’s small and comparatively unobtrusive. At 33 pounds, it’s also alarmingly light to those of us who expect serious speakers to provide a more substantial foundation for the drivers’ motion. The upside is that the MG-20, with cherrywood veneer and side rails that scored high with my spouse, is downright handsome. Its elegant surface covers a firmly braced structure of birch plywood that forms a trapezoid to reduce internal standing waves.

A bit more about the MG-20’s pedigree is also in order. Esoteric brought in veteran loudspeaker manufacturer Tannoy from England to handle some aspects of design and construction, and called on the services of Tannoy’s technical director, Alex Garner, to specify key elements in the design. The silver-coated internal wiring is from van den Hul, and the hardwired (no PC board) crossovers use British-built ICW polypropylene, audio-grade Clarity Cap capacitors and oversized steel-core inductors of laminated silicone. The terminals on the cabinet rear have five connectors for biwiring, with an extra terminal for the ground. (In my setup, the ground made no difference I could hear, so I left it unconnected.)

The specs claim the MG-20’s sensitivity is 89dB and its minimum impedance 3.7 ohms, which should make it a relatively easy load to drive, although beyond the range of microwatt amps. The frequency range at 6dB down is from 38Hz to 44kHz -- impressive at the top end, not so much at the bottom. I expected the speaker to have a hard time presenting convincing bass, and made a point of putting that on my listening checklist.

The MG-20’s base, which adds 36mm to the speaker’s height and 8.5 pounds to its weight, is made of a heavy metal and composite material and uses a proprietary system of three pinpoint feet. For some reason, the base is considered optional. Why a pair of bases, even high-tech ones, should cost $1500 isn’t entirely clear. But compared with the thin, sharp-pointed, wobbly footers that come free with the speakers (and which I removed about three minutes after installing them), the base is essential. It provided a much firmer footing for the speaker, and added to its low-frequency performance.


Mark Gurvey warned me about setting up the MG-20s and how long it would take to break them in. He noted that his own MG-10s had "needed to be burned in for 300-400 hours, and after that, the sound became much more natural, clear, and transparent."

The review samples, however, seemed to already be broken in. I nonetheless played them continuously for over ten days, but heard little change in that time. Nor did I have much difficulty finding good positions for them in my room. The manual notes that the speakers should work best when aimed slightly in front of the listening position, which is a new setup in my experience. I found that they worked best in my room when aimed straight at my listening spot from 9’ away, about 8’ apart, and 20" out from the front wall.

As much as I was interested in evaluating the entire speaker, I was curious to hear how those magnesium drivers sounded. I was able to compare Esoteric’s magnesium driver directly with SEAS’ 7" magnesium-alloy Excel model, which is used in one of my reference speakers, the Salk Sound Veracity HT3 ($4495/pair and up), as well as with the carefully designed and similarly sized paper drivers in my Triangle Stratos Australe references ($5699/pair). I also took advantage of attending a conference in Madison, Wisconsin, to drop in on the offices of Madisound, a supplier of loudspeaker kits and components. One of the kits they sell is the Thor, a two-way d’Appolito floorstander that uses magnesium-alloy drivers from SEAS. They also have a room where you can listen to their kits when they’re assembled and installed in cabinets. The opportunity was too good to pass up.

Besides those three comparison speakers, the other gear used in this review included an Esoteric X-03SE SACD/CD player, a Bent Audio NOH passive transformer linestage, a Conrad-Johnson Premier 350 power amplifier, Legenburg Apollo speaker cables and Hermes interconnects, ESP Essence Reference power cables, and a PS Audio Power Plant Premier power regenerator.


Long before the official break-in period was over -- in fact, almost immediately after I heard the first sounds emanate from the MG-20s -- I knew something was different. The sound seemed more solid, in a way more real, than I’d heard from any other speaker in my listening room. It was similar to the distinction between solid-state and tube amplification, where tubes provide a kind of roundness and reality that make some solid-state gear sound thin and artificial.

But I wasn’t immediately sold. (Note that my list of associated gear includes nothing with tubes.) My inner critic’s "But do I like it?" rang insistently in my ears -- what I was hearing differed enough from past experience that I had to not only listen to the sound, but come up with an explanation for what I was hearing before I was able to relax and get into it.

My experience has been that "solid and round" means "lacking in detail." But the MG-20 didn’t lack detail at all. For instance, in the complex orchestrations of Loreena McKennitt’s An Ancient Muse [CD, Verve B0007920002], I heard background instruments more clearly and was able to identify them more easily. There was also a more convincing quality to in inner identity of tones. For instance, I like trumpets to have the ripping "goes up forever" sound that they do in real life, and the MG-20 delighted me in how it expressed the high trumpet frequencies in Louis Lane and the Atlanta Symphony’s recording of Aaron Copland’s Fanfare for the Common Man [SACD, Telarc SACD-60648]. They even approached the speaker that’s my benchmark for high-frequency reproduction, the Reference 3A Grand Veena ($7995/pair). My sense is that this was the result of the nonresonant magnesium cones, and that in this respect, I was hearing the increased detail that Mark Gurvey had described. He confirmed this: "The solid sound means you’re hearing more data."

I also listen for internal variations in tone such as vibrato. Here, the MG-20 performed as well as the top speakers I’ve heard. For instance, in Maxim Vengerov’s performance of the Tchaikovsky Violin Concerto with Claudio Abbado and the Berlin Philharmonic [CD, Teldec 90881], his violin was expressive; I could easily hear the microtransients associated with his fingering and vibrato. Violins and horns in this recording, and these and female and male voices in other recordings, all had a very appealing solidity. The sound also motivated me to see what would happen if I kept pushing the envelope to get more detail. I added Bybees to the signal path and tinkered with the vibration control under components, and, unlike my experience with other speakers that start to sound thin when pushed in that direction, the MG-20s conveyed even more detail while maintaining the richness of the sound.

The MG-20’s bass performance, too, was surprising, given its specs. Here, the soft surround clearly had the intended effect: bass notes were very tuneful (though perhaps not quite as crisp as midrange tones), and went well below where I was anticipating they would end. Indeed, the MG-20 was far closer to standalone, no-subwoofer-needed speakers than the Madisound Thor with SEAS magnesium drivers, and sonically came close to matching the bass performance of my reference Triangle Stratos Australe, which is rated as 3dB down at 34Hz (vs. 6dB down at 38Hz for the MG-20). Nonetheless, it turned out that Esoteric recommends the use of subwoofers, and uses REL subs when demonstrating their speakers at audio shows. "We recommend that a subwoofer be used with the MG-10 and perhaps also the MG-20, depending on the music you listen to," said Gurvey.

The most telling differences I found, though, came from comparing the tonal quality of the drivers in the three reference speakers with that of the MG-20’s midbass driver. First was a head-to-head comparison with the SEAS magnesium-alloy midrange driver in the Salk Sound Veracity HT3. The music I used for this comparison was the Fry Street Quartet’s IsoMike recording, with Ray Kimber of Kimber Kable, of the Adagio cantabile of Haydn’s String Quartet in D Minor, Op.9 No.4 [CD, IsoMike FSQCD4], which opens with several minutes of predominantly midrange violin and viola passages.

I was expecting subtle differences between the drivers, but I was surprised at how distinct they actually were. The SEAS driver conveyed massive detail -- perhaps even slightly more than the Esoteric magnesium driver -- but at a cost. The SEAS sounded metallic and brittle, with a hard, edgy tone. This effect was confirmed in listening to the Madisound Thors, which were detailed and threw up an impressive soundstage, but again were affected by the distinct metallic coloration of the SEAS driver. The deceptive part was that this resonant aspect of the SEAS was easy to overlook in ordinary listening; my brain could be persuaded to interpret it as "lots of detail" and nothing more. But the close A/B comparison revealed the very real difference between this and the Esoteric driver, which sounded far more true to the natural timbres of instruments than the SEAS.

Perhaps the most important comparison was against paper-cone drivers, which Mark Gurvey had generically labeled "colored." My Triangle Stratos Australes aren’t the last word in detail or lack of distortion, but because their development included much careful listening, they offer an extremely realistic representation of the timbres of acoustic instruments. I A/B’d both the Triangles’ full-range performance and their midrange drivers and tweeters against the MG-20s, and their performance was much closer than I imagined it would be.

Up against the paper-coned Triangles, the Esoteric revealed just the slightest hint of its metal composition. The metallic resonance that had been clearly evident in the performance of the SEAS drivers was present in a just-noticeable amount in the Esoteric driver, and in this respect, the Triangles had the slightest advantage in accurately portraying acoustic timbres. But the Triangle drivers couldn’t compete with the Esoteric driver in offering convincing detail, the ability to accurately convey complex passages, and, perhaps most tellingly, in the fullness of their sound. This last effect was the final piece of evidence for me that the Esoteric speaker’s unique sound was due not to a smearing of detail, but was more likely the result of the damped magnesium cone not adding resonant "hash" to the tone.

Overall, in my informal shoot-out, the Esoteric driver’s virtues carried the day. Anyone interested in a fine speaker for listening to acoustic music should consider it high on their list -- and those who listen to other types of music should check it out, too.

Considerations and conclusions

To be an Esoteric product means to be continually evolving. The next steps in the evolution of the MG speaker line appear likely to be a speaker that offers extended low frequencies, as well as a speaker for home-theater use. Mark Gurvey mentioned to me that a 10" magnesium driver is under development, as is a center-channel speaker. According to the manufacturer, although these products are being considered, they may or may not make it to market. An MG-20 with an extended low end would be one great speaker, I’d bet, in part because the burden of low-frequency reproduction would be removed from the midrange drivers and they would likely become all the clearer. But even as it is, the MG-20 leaves very little to be desired. It’s one of the most satisfying speakers I’ve ever listened to.

The MG-20 conveys detail while making the most of what’s on the recording. It’s like an oversized catcher’s mitt: capable of handling most any knuckleball thrown at it and making it sound as good as it can. My initial suspicion was that they were making recordings sound better than they actually are. After careful listening and comparing, I believe that many (if not most) speakers make recordings sound worse than they actually are. During my listening tests with the MG-20, I learned that many drivers have resonances that largely go unnoticed but still significantly affect the sound they produce. My sense is that the MG-20 is not so much forgiving of recordings’ flaws as revealing of the quality that actually exists on many recordings.

There will be those who wonder whether spending $10,500 for a pair of two-way speakers with 6.5" main drivers is worth it. That’s not a call I can make, but I can say that it will be fairer to make your decision based on how the MG-20s sound to you rather than on whether you think the size of their components make them a good value. Few speakers near this price will allow you to hear music reproduced as authentically and as enjoyably.

The Esoteric MG-20 has changed what I thought was possible from a dynamic driver, and has taught me a lesson in how they improve on the performance of competing magnesium-alloy and paper drivers. As with most technological breakthroughs, personal taste enters the picture -- the MG-20 sounds different enough to require an audition before you come to any conclusion of your own. Count me among those who like them very much.

...Albert Bellg

Esoteric MG-20 Loudspeakers
Price: $10,500 USD per pair, including bases.
Warranty: Three years parts and labor.

Esoteric Division
TEAC America, Inc.
7733 Telegraph Rd.
Montebello, CA 90640
Phone: (323) 726-0303

E-mail: esoteric_info@teac.com
Website: www.teac.com/esoteric

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