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MartinLogan Impression ESL 11A Hybrid Electrostatic Loudspeaker

MartinLogan Impression ESL 11A Hybrid Electrostatic Loudspeaker

MartinLogan’s new Impression ESL 11A is a direct replacement for the company’s Montis that I reviewed so enthusiastically almost three years ago. Like the earlier model, which is priced identically to the new one at $9995 a pair, the Impression is the third from the top of the company’s floorstanding Masterpiece line and consists of one of ML’s proprietary CLS electrostatic panels affixed to an enclosed dynamic subwoofer. Inasmuch as both my colleague Dick Olsher and I have written extensively about MartinLogan speakers in the past few years, I refer readers to our respective reviews of the Montis (Issue 244) and the Summit X (Issue 209) for technical and historical background, and to Dick’s chapter on the company in TAS’ Illustrated History of High-End Audio, Volume One: Loudspeakers.

The main talking points are two: First is ML’s electrostatic panel, which it designates CLS for “Curvilinear Line Source,” owing to the mild horizontal convex curve designed to overcome the typical narrow high-frequency dispersion of flat panels. Second is the use of powered dynamic woofers to surmount the usual bass and dynamic limitations of most ESLs. Owing to the superior transparency of electrostatics and flat panels’ dipole radiation pattern, matching ESL panels to dynamic woofers has proved vexing both for designers and for audiophiles who prefer to add aftermarket woofers. In recent years and models, however, MartinLogan has managed to solve the integration problem virtually to perfection. Since then, however, evidently feeling that “virtually” is not close enough, ML’s engineers—largely Joe Vojtko, whom his colleagues often refer to as their resident genius—have completely redesigned the woofer section for all-around superior performance, which shall be the focus of this review.

Glance at a single Impression from the front and you’d be forgiven for thinking it’s identical to the Montis. Look at it from the side and the back and you see that the compact, almost square woofer housing of the earlier model and its ten-inch driver have given way to a cabinet extending almost two feet back that houses a pair of eight-inch woofers, one front-mounted, the other rear-mounted. (A friend of my wife’s inquired if they were some kind of contemporary chair.) At first I assumed the cabinet was to allow the woofers to mimic the panel’s dipole radiation. In fact, with help from the digital circuitry, the two woofers, crossed over at 300Hz, are made to work in a kind of sliding phase arrangement whereby the phase shifts with frequency in order to suppress the backwave and also to prevent frequency-specific cancellations that may result from woofers arranged to mimic dipole radiation. According to Vojtko, digital manipulation of phasing directs most of the two woofers’ output forward, not toward the back wall, an arrangement claimed to facilitate setup and speaker placement: “The sliding phasing is weighted toward the frequencies where directionality is more critical, where the manipulation of the phasing is taking place, and the woofers come into phase together at the lower frequencies.” This does address what has always been one of the thornier problems with ESL/dynamic hybrids, namely, that optimal placement of the panels does not necessarily correspond to optimal placement of the woofers, hence the preference among many audiophiles for the positional flexibility of stand-alone woofers.

But the ace up ML’s sleeve in the Impression is the provision for Anthem Room Correction (ARC), a highly effective digital-signal-processing program designed to cope with typical bass response anomalies of most listening rooms. I say “provision” because while the speaker comes equipped with the circuitry, it can’t be activated without purchasing the ARC microphone, which is an optional accessory priced at $100. In other words, if you don’t purchase the microphone, then the Impression can be used as-is without DSP, just like previous ML speakers. But, as I’ll come to, the Anthem feature is so effective it’s hard to for me to believe that any user, once committed to ten grand, wouldn’t spring for the extra hundred bucks.

Using ARC is quite easy once you get it to lock onto the online program that allows it to work. Unfortunately, if you’re an Apple-man like me and are PC-phobic to boot (me again), this is easier said than done. I eventually got it to work properly thanks in no small part to my wife, who is ambidextrous when it comes to computers and has a PC laptop. But if you’re an Apple-only household, you might want to ask your dealer to do it or else enlist the help of a PC-savvy friend.

As I say, once you’re hooked up and online, it’s a snap: Set up the microphone according to the instructions, then sit back for the few minutes it takes for the application to do its work. (A before-and-after curve is displayed on the screen.) Once it’s done, it’s done, though of course if you change your listening location or move the speakers, then you must redo the procedure. It should go without saying but I’ll say it anyhow: Prior to engaging ARC, you are advised to make every effort to place the speakers optimally in your room. As remarkable as digital room correction is when it works—and this Anthem system certainly works a treat—it’s most effective when it corrects speakers that have already been set up to good or better advantage.

Before I get into the sound, let me take you on a tour of the signal path and the woofer cabinet’s back panel. From the binding posts, the full-range signal goes through two filters, an analog 300Hz high-pass filter to the ESL panels and a digital low-pass filter to the woofers. The low-pass signal is digitized, filtered, and then passed through the ARC circuit. The corrected signal is next sent to a switching amplifier and to the woofers (back in analog). If you’re a digi-phobe—in my opinion, a really silly prejudice in this day and age—then know that if you opt for the ARC feature, at least part of the signal will have undergone A-to-D and D-to-A conversion.


As for the back panel, in addition to the binding posts there is a bass-level knob, a midbass level switch, the ARC in/out switch, the ARC set-up input (a mini-USB connector), and the ARC Setup Speaker Link (which requires an RJ-45 [Ethernet] connector), plus two status lights, one for the whole speaker, the other for the ARC equalization. The speaker-link connector, which ties the right and left arrays together, allows the ARC to program both speakers simultaneously. If you don’t have the requisite cable, all it means is the minor inconvenience of programming each speaker separately. The bass-level control is basically a tone control that operates below 75Hz while the midbass level boosts or cuts the bass 2dB at 200Hz. Both of these controls operate independently of ARC and regardless of setting are bypassed while ARC is in calibration mode.

With ARC on hand, you might wonder why these additional controls are there in the first place. Well, as noted, the Impression comes ARC-ready but not ARC-functional unless you purchase the optional microphone. These controls allow you a modicum of control over the mid-to-low bass and the upper bass apart from ARC. But even with ARC, these circuits come in handy for additional trimming and other fine-tuning of the bass, including compensating for bass characteristics of recordings, if you care to use them for that. For example, while the ARC does a very effective job of addressing room acoustics, a bass-shy recording—like a great number of my favorites by Szell and the Cleveland Orchestra—is still a bass-shy recording and will sound that way. The bass-level control is surprisingly effective for correcting this even after you’ve performed the room equalization. As for the 200Hz switch, again, many audiophiles like a lean upper bass which the Impression’s 2dB cut will help provide; at the same time, if you like more warmth in this area, then the 2dB boost will help, too.

Impression Bass with and without ARC
Let me say it up front: The Impression 11A with its built-in ARC engaged has provided the best bass response I’ve ever heard in my room in the areas of overall smoothness of response and of clarity, definition, and pitch differentiation. A few examples: One of my favorite recordings is the Sitkovetsky arrangement of Bach’s Goldberg Variations (Nonesuch) for string orchestra and harpsichord. There is only one double bass in the group, yet for the first time I heard it with a foundational definition that was rather revelatory. I don’t want to suggest that without ARC the bass is inaudible—far from it—only that with ARC you can follow the musical line with greater ease and a less effortful concentration, and there is a greater impression of air around it. The same holds for the one non-stringed instrument, the harpsichord, which is also separated out and easier to hear and to follow. In saying this, I don’t want to give the impression of anything unnatural or clinical in this clarity—rather, it’s just easier to listen into, as it were, yet at the same time allowing it to assume its rightful place in the overall texture without being submerged or calling undue attention to itself.

The same applies to another string orchestra arrangement—Bernstein’s recording of Beethoven’s Opus 131 string quartet with the full complement of the Vienna Philharmonic’s string section, including (where appropriate) the basses doubling the cellos. This is one of my desert-island discs. Played over these Impressions I didn’t hear details I’ve never heard before, but I was rewarded with clarity of line, texture, and articulation throughout the bass range that filled me with new respect for this inspired and inspiring performance and the way it is recorded. Another of my favorite recordings, Kei Koito’s organ recital of Bach [Claves] displays the same virtues of increased clarity and definition. The organ is a notoriously difficult instrument to record because it’s a difficult instrument in and of itself. Many churches tend toward a highly reverberant acoustical character that even in the best of hands militates against textural clarity. And truly full-range organ recordings that are recorded clearly can become muddy in systems that can’t handle the bass, especially when driven too hard.

This Claves organ recording is considered by Diapason magazine to be a textbook example of how to record the instrument optimally. The reason, I assume, is that it displays an ideal combination of clarity, articulation, reverberation, extension, and power—all of which (save only the last attribute) is pretty much what you get from the Impressions. And make no mistake; you certainly hear plenty enough power, especially in view of the relatively diminutive woofers. But that sense of ultimate room-filling bass power, plus crunch and slam—the kind I hear from my reference Harbeth Monitor 40.1—is “merely” excellent here without being truly outstanding. I believe this is because there is only so much you can get out of small drivers such as these eight-inch transducers, especially given the lack of any sort of baffle reinforcement. Having said that, however, I should add once you set aside these special categories of big music, only rarely throughout the evaluation period did I ever feel any serious shortcomings or limitation in the 11A’s bass response.

Fortunately, however, there is an easy remedy at hand for those who love the big stuff, though it comes at a cost: Add an REL subwoofer. Any number of good subwoofers will do the trick, but I favor the RELs because they are designed to be true sub-bass systems, that is, to add that last half-octave of bottom-end extension to speakers that already have excellent bass response. In that respect, MartinLogans, like full-range Harbeths, make ideal partners for RELs. The only potential drawback is that inasmuch as the RELs take the signal from the main amplifier’s speaker terminals, the ARC cannot operate upon the subwoofer. I didn’t find this a problem. For one thing, the bass acoustics of my room are very good and don’t present any oddities. For another, because the 11A’s bass response is already so extended, there is no need to set the crossover of the REL any higher than its lowest position. After that, get the phasing right and adjust the level, and you’ll be rewarded by some of the cleanest, most precise, articulate, and powerful bass you can buy. The difference is really audible on an awesomely spectacular recording like the Zander Mahler Sixth with the hammer blows in the last movement. By themselves the Impressions render these sensationally; with the RELs you feel them in the pit of your stomach.

Are there any downsides to ARC? Only one: As employed by MartinLogan, “all” ARC can do is make the bass response as accurate as possible in any given room. But this means that it will also “correct” characteristics you might find pleasing, such as a bit more warmth or power owing to standing waves or other modal effects. Objectively you will hear improvement, but your subjective response may evaluate it differently. I would have no problem living with the bass response of a un-ARC’d pair of carefully placed Impressions, but, though I do not consider myself a detail-over-everything audiophile, and the acoustics of my room are very attractive, I always preferred these speakers with ARC-corrected response.


The Curvilinear ESL panels
This needn’t require a lot of verbiage because, with one exception, the curvilinear ESL panels perform the way I described them in my review of the Montis. First, they do an astonishing job of projecting height, so that well-recorded vocalists and instrumentalists really are presented with an extraordinary sense of life-sized realism. Second, MartinLogans are renowned for their clarity, transparency, detail, and dynamic range, and these new ones are no exception, not least, I think, because the panels are freed from having to produce the lowest frequencies and also because the room correction pays dividends further up the frequency band. Third, they produce a fabulously wide and deep soundstage. Big music such as large orchestral-choral works and nineteenth-century operas become quite thrilling in the sense of projected size and scale. Those of you who get off on soundstaging that extends beyond the boundaries defined by the speakers are going to love the Impressions.

This last, however, is a not without a penalty. The rationale behind the curved panels is to overcome the high-frequency beaming of most panel speakers. And to some extent this works surprisingly well, not so well as the omnidirectional Muraudio ESLs, but those who find Quads of any vintage entirely too directional will find these more satisfactory or at least much less unsatisfactory. The sacrifice, however, is less precise imaging. One member of my listening group was driven crazy by the Impressions in this regard (and also by other MartinLogans) because he felt that things never occupied a precise and defined place. I personally feel he is overreacting here. I like precise imaging but I don’t have a fetish about it, and while I’m aware of what my buddy is talking about, I didn’t find that it much impaired my enjoyment of the Impressions. But he does have a valid point: There’s always a very subtle vagary about the positional placement of solo instruments and vocal soloists within the soundstage. (See Robert E. Greene’s review of the Sanders Model 10e in Issue 276 for some reasoned speculation about the effects of a curved panel.)

This leaves me with only one additional matter. Perhaps the thing I liked best—indeed, loved—about the Montis was its tonal balance, which I described this way: “ever so slightly forgiving in the 2k–4k region, and above a mild sloping response. Together these characteristics are neither gross nor obvious, and do not manifest themselves as coloration or a significant deviation from overall neutrality. The effect is rather more like a shift in perspective from, say, row A–G to H–P. This means that with recordings that are far too closely miked, which is to say most recordings, the Montis will actually sound more natural in ways that a literally accurate speaker will not. If I were to search for a thumbnail characterization, I’d say its tonal character is reminiscent of what in the old days used to be called ‘New England’ sound: essentially neutral, uncolored, smooth, civilized, maybe a bit polite. But with one huge difference: No ‘New England’ speaker I’ve ever heard was ever capable of a presentation as full of life and vitality as the Montis, able to scale instruments to life size and bring the room as alive with music. And no such speaker ever sounded as open and free from a box as this one.”

In the Impression 11A, however, a distinct Yang character has replaced the Montis’ lovely Yin personality with a presentation that is crisper, sharper, more forward, and, depending on the recording, even a bit aggressive. There’s also an impression of glare, a subtly “shouty” quality that, again depending on the recording, can be rather pronounced and never entirely disappears. Allow me to call upon an obviously flawed recording to indicate more clearly what I’m talking about here. Bernstein’s first recording of Appalachian Spring [Sony] is notoriously bright. Over speakers that are a bit recessed throughout the presence region and that do not rise above that—the Montis or Harbeth’s wonderful SuperHLP5plus—the recording still sounds bright but is listenable. Over speakers that are essentially neutral—my reference Harbeth Monitor 40.2 or Quad 2805 ESL—the recording sounds as excessively bright as it is, indeed, almost fierce, but remains tolerable. Over the Impression the fierceness really takes over and it becomes a recording I don’t especially want to listen to—a pity inasmuch as this remains the best performance and interpretation of the piece that I know (I was glad to have McIntosh’s superb new C52 preamplifier, with its seven bands of equalization on hand for review, so I could tame the recording).

As I say, that recording is flawed, but it illustrates the issue. In case you think I’m relying on what we all know is sometimes notoriously unreliable audio memory, I should point out that the review pair of the Montis are now owned by a couple who are industry professionals, live nearby, and are very close friends: Rarely a month goes by that I don’t get to listen to those speakers two or three times. As in all judgments like this, we’re dealing with matters of taste and I must emphasize that these new Impressions are very much in line with the trend of speaker sound these last twenty years, the kind of sound that a lot audiophiles, not to mention speaker designers, seem to like. There is no gainsaying the fact that all the typical ML virtues are here in abundance. So if you’re tempted—and there is a great deal to like about these speakers assuming the tonal balance appeals to you—an audition is mandated.

Specs & Pricing

Type: Hybrid electrostatic floorstanding loudspeaker
Driver complement: 1 XStat CLS electrostatic transducer panel (44″ × 11″); dual 8-inch Powered Force Forward woofers with dual 275Wpc amplifiers and 24-bit Vojtko DSP Engine
Frequency response: 29–23,000Hz ±3dB 
Recommended amplifier power: 20–550 watts
Impedance: 4 ohms, 0.6 at 20kHz
Dimensions: 60.75″ × 11.9″ × 27.4″
Weight: 90 lbs.
Price: $9995/pr.

2101 Delaware St.
Lawrence, KS 66046
(785) 749-0133

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