MartinLogan Montis loudspeaker

One of my formative audiophile experiences was the first time I heard electrostatic speakers. I walked into an audio store and heard music played by a live jazz combo. But where were the musicians? I saw none, though I did notice a couple of room-divider panels in the part of the store where the music seemed to be coming from. Eventually, it dawned on me that these must be loudspeakers—but they sounded like no other speakers I'd ever heard, and nothing like the Advents I had at home.

Those room dividers turned out to be KLH Nine electrostatic speakers. My Advents, good as they were, sounded like speakers; these sounded more like live music. The price was something like $2000/pair, more than 10 times the price of the Advents—completely out of my price range at the time.

Back then, I had a habit of checking the Stereo Equipment section of the newspaper's classified ads, looking for bargains, and a few years after my initial experience with the KLH Nines, I saw an ad for a pair of them. It wouldn't hurt to just go and hear them, would it? I ended up buying them for a somewhat-manageable $500, and I was happy. The speakers sounded terrific—when they worked. The tweeter was particularly trouble-prone; after a while it would begin to make buzzing sounds that, I discovered, indicated arcing. I replaced it three times, and always dreaded that it would start acting up again. Then there was a problem with the power-supply-and-crossover module, which was potted in paraffin wax and had to be shipped to Boston to be fixed. This happened twice. I finally lost my patience and got rid of the Nines, but not without regret. I later owned a pair of original Quads, which were more reliable, but their limited dynamic range and lack of bass bothered me. I tried adding subwoofers, but that solution wasn't entirely satisfactory.

I've long admired the electrostatics made by MartinLogan, and at one point was about to review one of their hybrid models when those plans fell through. Then, a few months ago, MartinLogan's then PR agency suggested that I consider reviewing either the entry-level ElectroMotion EM-ESL ($2195/pair) or the about-to-be-introduced Montis ($9995/pair). I'd heard the EM-ESL at a dealer's and had been impressed by its sound, especially for the price—but I was even more impressed by the sound of the Summit X ($14,995/pair). The Montis uses the same electrostatic tweeter/midrange drive-unit as the Summit X, but has a single 10" woofer instead of the Summit X's two. I went for the Montis.

Not in Kansas Anymore
I've always thought of MartinLogan as being located in Lawrence, Kansas—and, indeed, that's the address on the company's website. I was then surprised when the review samples of the Montis arrived, and stickers on the boxes said "MADE IN CANADA." I knew that MartinLogan, like Paradigm and Anthem, is now owned by ShoreView Industries, of Minneapolis, but hadn't realized that all ML speakers are now built in the same Canadian factory where Paradigm speakers and Anthem electronics are made. (Product development for MartinLogan is still in Kansas.) To ensure that MartinLogan speakers maintain the level of quality established in the Kansas facility, they've set up a production line in the Mississauga, Ontario factory dedicated to MartinLogans, and have thoroughly trained the workers in the technology required for these speakers. In fact, ShoreView Industries used the transfer of production from Kansas as an opportunity to automate critical parts of the manufacturing of the electrostatic drivers, thus tightening tolerances and improving consistency. I was impressed by the obvious attention to detail and concern for maintaining the highest possible quality in manufacturing.

MartinLogan specifies the Montis as being 59.3" high, 12.7" wide, and 18" deep. This is correct in the sense that a shipping box for the speaker must accommodate these dimensions, but most of the 18" depth is accounted for by the woofer box; the depth of the electrostatic tweeter/mid driver, including the frame, is only about 11/4". Compared to MartinLogan's Prodigy (see Larry Greenhill's review), the Montis is shorter by more than 7.7" and narrower by 4.5". Larry described the Prodigy (which weighs 133 lbs compared to the Montis's 58 lbs) as "imposing," which is not a word I would use to describe the Montis—perhaps svelte or elegant. The Montis's size and proportions looked just right in my 16' by 14' by 7.5' listening room, the perforated steel stators of its electrostatic tweeter/mid producing a see-through effect.

By almost any standard, the Montis is beautiful. The review samples' bass cabinets were finished in hand-rubbed, glossy black cherrywood, which does look almost black in low light but is an attractive dark red in brighter light. The middle third of the top of the bass cabinet has a black metal trim, curved to match the design of the tweeter/mid electrostatic element, and features the MartinLogan logo, which lights up in blue when the speaker is playing. (It can be turned off.) On the rear panel is a single set of five-way binding posts—again, very stylish, and easy to tighten by hand if you're using spade lugs—and a knob for setting the woofer level. The speaker comes with four rubber feet installed; these can be replaced with spikes (provided). When feet or spikes are fully screwed in, the electrostatic panel is tilted slightly back; this can be adjusted by partially unscrewing the front or back feet.

MartinLogan's initial claim to fame was the development of the Curvilinear Line Source (CLS) electrostatic panel, designed to prevent treble beaming and the resulting highly restricted sweet spot produced by flat panels. Instead of flat electrode panels, the CLS driver has perforated metal panes that are bent to produce a gentle curve. The concept may seem simple, but to put it into practice requires a great deal of technical expertise and meticulous care in manufacturing. The distance between the diaphragm and each electrode, or stator, must be the same throughout the entire panel, to avoid hot spots in the response. Achieving this is partly a matter of manufacturing tolerances—the curve must be exactly the same for each stator—and is partly maintained by the spacers that keep diaphragm and stator apart. These, too, must be manufactured to a high tolerance. As far as I know, MartinLogan is the only manufacturer of electrostatic speakers to use curved panels. The Sound Lab electrostatics, which appear to be curved, actually have faceted panels with flat sections.

Extensive information on electrostatic theory and details of MartinLogan's technologies are available at MartinLogan's website. The Montis electrostatic panel is the largest used in any of ML's current electrostatic hybrid speaker models. The MartinLogan CLX ART has electrostatic panels that are larger still, but the CLX is nominally a full-range electrostat, not a hybrid. (I say "nominally" because the CLX's low-end limit is specified as 56Hz, and in every demo I've heard, it's been combined with a pair of subwoofers.) The Montis's electrostatic panel is a true dipole, radiating to the front and to the rear with no attenuation of the backwave. The crossover to the woofer is at 340Hz. My first thought was that this was on the high side—when I used a subwoofer with the KLH Nines and the Quads, I used to set the crossover frequency in the 80–100Hz range. However, that comparison is misleading. The KLH Nine and the Quad had separate midrange drivers and tweeters, with built-in crossovers. The Montis's electrostatic panel functions as midrange and tweeter, so it doesn't need a tweeter/mid crossover. With a subwoofer, the KLH Nine and the Quad were in effect three-way systems with two crossovers; the Montis is a two-way system with a single crossover.

PowerForce Bass is MartinLogan's name for their powered subwoofer. On the face of it, the Montis's woofer design seems pretty straightforward: a 10", high-excursion, aluminum-cone driver in a sealed box, powered by a 200W amplifier. However, a great deal of the developmental engineering work at ML has dealt with perfecting the blend between the electrostatic panel and the dynamic woofer. With the Montis, their solution was to use an analog high-pass filter derived from the CLX, and digital signal processing (DSP) for the woofer. MartinLogan calls the latter the 24-Bit Vojtko DSP Engine, after Joe Vojtko, the company's chief audio technologist; it functions as a low-pass filter, equalizer, and limiter. The woofer-level control, centered at 100Hz, permits some matching of the bass performance to the room.

Planar speakers, including electrostatics, are considered difficult to set up, and that was certainly true of the KLH Nines and the original Quads. Maybe I was lucky, but the Montises sounded fine plunked down more or less where I usually place speakers in my room (along the 16' wall), and their performance got only better when I adjusted the usual parameters of listener-to-speakers distance (as close to equal as possible), speakers-to-front-wall distance (ditto), and toe-in and vertical angles. The resulting angle between speakers and listening seat was close to the classic 60°, with the top of the electrostatic panel of each Montis 36" from the front wall.

I adjusted the toe-in angle first using the flashlight method suggested by MartinLogan: point a flashlight at each speaker, and adjust toe-in so that the reflection of the light is in about the same place, left and right. I then tweaked the angle a bit by ear, trying to produce as wide a soundstage as possible without losing center fill. For the KLH Nines and the Quads, the tweaking of toe-in angle was very critical—even the slightest difference between the left- and right-speaker angles caused a major lateral shift in the soundstage, with an attendant L/R difference in tonal balance. The Montis's curved electrostatic driver made for a much less critical adjustment of this parameter.

Next was to replace the rubber feet with spikes and adjust the vertical angle, tilting the speaker a bit forward from the standard backtilt, and making sure that the angle was the same for both speakers. I used a plumb line. Once I was satisfied with the speaker positions, I played with the bass-level control while listening to recordings with appreciable midbass and low-bass content, such as Mickey Hart's Planet Drum (CD, Rykodisc RCD 10206).

2101 Delaware Street
Lawrence, KS 66046
(785) 749-0133
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Et Quelle's picture

Those blue lights seem cool for a while then like they're looking at you. 4 ohms should be better; less resistance. The tube sound is so realistic and evidently so are the Montis, even if you have to dust em.

dmusoke's picture

Nice review ... but i'm puzzled to hear of no comparison to the Spires, the speaker it replaced. They both use the same exact panel and woofer, with the Montis performing the filtering in its DSP versus the analog filtering used in the Spires that was from the venerable CLX series. $1500 more is the price one has to pay to have the DSP compared to the Montis. The two speakers are practically sonically identical (+99%) to most listeners but the Spires can be had for $5000 or so now since they've been discontinued.


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