MartinLogan Summit X Loudspeakers
Category: Innovation in Design
Loudspeakers -- MartinLogan Vantage, Summit
Power amplifier -- Halcro MC50
Preamplifier -- NuForce P-9
Source -- Marantz DV-9600 SACD/CD/DVD-A/V player
Interconnects -- Synergistic Research Tesla Apex and
Speaker cables -- Synergistic Research Tesla Apex
Power cords -- Synergistic Research Tesla Hologram A and
D, Precision AC
Power conditioners -- Synergistic Research PowerCell, PS
Audio Noise Harvesters, DIY parallel filter
Accessories -- DIY isolation amp stands, Bright Star
Audio and Black Diamond Racing isolation devices, Shakti stones, Synergistic Research
TeslaPlex AC outlet, Acoustic Revive CB-1DB Receptacle Base Plate and CFRP-1F Carbon Fiber
Outlet Plate, Mapleshade Silclear contact enhancer
I am a longtime electrostatic-speaker
junkie who has owned several MartinLogan models, including my current Vantages. When SoundStage!
publisher Doug Schneider asked if I was interested in reviewing the new Summit X ($13,995
USD per pair), which replaces MartinLogans Summit, we both knew it was an offer I
In a world in which ultra-high-end speakers can cost upward
of $100,000/pair, $14,000 for a presumably world-class brace of speakers could, by some,
be considered pretty reasonable. But $14,000 is a lot of money even in the best of
economic times, and for most people these days -- especially if youre a working
stiff like me -- its far more.
Before receiving the Xs, I wondered if they would take me
significantly closer to the promised land of electrostatic nirvana than I had ever been. A
short while later, two familiarly tall, slender MartinLogan boxes arrived at my door. As
they say in the world of sports, this review was on.
eXploring the Summit X
The Summit X is a hybrid loudspeaker: an electrostatic
panel paired with two 10" dynamic woofers, each powered by their own 200W amplifier.
The most advanced hybrid in MartinLogans lineup, the X is eclipsed in stature and
price by only two models of the companys CLX line of full-range electrostatic
speakers, both of which cost over $20,000/pair. As discussed below, the X is jam-packed
with technology, any discussion of which requires the negotiation of what seems a
record-breaking number of trademarked names.
The first thing anyone will notice about the X is its
transparent XStat panel, which rises from the woofer cabinet. This panel, gently convex in
MartinLogans Curvilinear Line Source (CLS) shape, is responsible for reproducing all
of the audioband down to the crossover to the woofers, at 270Hz. According to ML, the CLS
shape reduces sidewall reflections, and thus minimizes unwanted interactions with such
things as ceilings, floors, and walls, while minimizing late arrival time.
The XStat panels frame, which ML calls the AirFrame,
is manufactured from aerospace-grade billet and extruded aluminum alloy. Extremely rigid,
it provides electrical and acoustical isolation that dont interfere with its ability
to radiate sound in dipole fashion, which tends to cancel out sounds at the edges of the
speakers, further reducing sidewall reflections. A proprietary vacuum-bonding process
ensures the uniform tensioning of the AirFrame and makes possible the precise tolerances
to which they must be made.
This panel comprises two large exterior steel stators, an
almost weightless diaphragm of Mylar-like film coated with a conductive material, and
ClearSpar spacers that keep the stators from touching the diaphragm. Theyre fused
with an aerospace adhesive whose strength exceeds that of welding. The stators sandwich
the diaphragm and remain stationary while the speaker is in operation. They also transfer
to the diaphragm the source signal, which, as described below, directs the
diaphragms movements back and forth to create the sound.
To permit sound to pass through them, the stators are
perforated. In developing their MicroPerf technology, MartinLogan has reduced the size of
the perforations and increased their number over the companys earlier models. This
not only nearly doubles the diaphragms radiating area and, ML claims, allows the
Summit X to attain significant improvements in performance, it also makes possible a
speaker about half the size of the companys earlier behemoths.
When the Summit X is operating, its diaphragm holds a fixed
positive charge. A transformer changes the power from an amplifier into two high-voltage signals that are then sent to the
stators in opposite polarity: one positive, one negative. As the amplifier signal changes,
the polarity of the stators flips between front and back, causing the diaphragm to be
rapidly pushed and pulled between the stators. This "push-pull" design is said
to cause the diaphragm to precisely and rapidly follow any changes in the signal.
The Xs two dynamic Controlled Dispersion PoweredForce
woofers have 10" aluminum cones. One woofer fires forward, from the front panel, and
the other downward, through the base. According to ML, these woofers extend the Xs
response to as low as 24Hz, territory typically claimed only by freestanding subwoofers.
The woofers are enclosed in their own sealed cabinet.
The X uses MLs newly designed, hand-built Vojtko
crossover, based on technology trickled down from the CLX line. As discussed below, this
crossover must facilitate the integration of the outputs of the electrostatic panels and
the dynamic woofers. The longstanding problem in pairing these two types of transducers is
that the panels are so much faster than the woofers that their outputs dont
integrate with each other well enough to produce a seamless melding of upper and lower
frequencies. Over the years, MartinLogan has made steady progress in solving this problem.
A peek at the rear of the Xs cabinet reveals 25 and
50Hz low-frequency equalization controls. These allow the speakers to be tailored to
accommodate individual room acoustics. The listener can raise or lower the speakers
feet to adjust the speakers controlled vertical dispersion, or tilt the X from -1 to
+11 degrees from the vertical.
Finally, "just because its cool" (per
MLs website), each Summit X has no fewer than three lights. One illuminates the rear
controls, another the blue MartinLogan logo, and the third casts the Xs spike-raised
underbelly in a piercing white glow that resembles something youd see illuminating
the underchassis of a low-rider. But if glowing speakers arent your thing, any or
all of the lights can be turned off.
Setup: X marks the spot
Unpacking the Xes was much easier than Id imagined it
would be. And as each speaker weighs only 75 pounds, I was able to set them up myself.
The Xes are a bit larger than my Vantages; I was concerned
that the former would be too large for my medium-sized room (12 x 22) and thus
sound boomy. One nice thing about the active woofers is that if you do run into this
problem, you can always decrease the woofers output by adjusting the 25 and 50Hz
controls. It didnt take me long to get these settings where I needed them. Of
course, the right settings for these controls will be different for every room.
As with many speakers, placement of the Xes was critical.
After much experimentation, and taking into consideration the narrowness of my room, I
wound up placing the speakers 7 apart, and my listening chair about 8 from
their midpoint. And, because electrostatics often require lots of breathing room, I
positioned them about 2 from the front and sidewalls.
I used about 30 degrees of toe-in -- any more and the Xes
sounded a bit too bright, much less and the soundstage became diffuse. Because I tend to
slouch down in my chair when listening to music, I adjusted the rake of the speakers to
tilt back only about 3 degrees.
I fed the Xes a steady solid-state diet courtesy my Halcro
MC50, a 200Wpc switching amplifier. Note that the active woofers, which have their own
200W amps, make the X a speaker much easier to drive than some of MLs earlier
models; they dont necessarily need as powerful an amp as many might think.
Nonetheless, youll likely not want to pair them with an ultra-low-power girly-man
Performance: X is for X-ray
First up was Paul van Dyks Global (CD, Gmbh
& Co. KG 9201-2). The electronic nature and grinding beat of van Dyks
progressive house music make it an album that most would not choose to audition
electrostatic speakers, but theres more to Global than its addictive rhythmic
pulse. Present in the mix are sweeping synthesizer riffs, luxuriant melodies, and sexy
Listening to any track on Global demonstrated that
the Summit Xes could move more than enough air in the lower octaves to reasonably rock my
house. More than that, the X unmistakably had that MartinLogan signature sound: clear and
open, masterfully layering the various synthesized sounds and flushing out their alluring
midrange warmth. Call it a magical transparency and immediacy that few conventional
dynamic speakers -- and none that Ive heard at or near this price -- can match. To
my surprise, I found that the X displayed a significantly warmer tonal balance than I was
used to hearing from MLs prior offerings.
But after listening for a bit, it was time to move on.
While electronic music will benefit from a pair of well-designed speakers, it wont
fully demonstrate those speakers ability to, among other things, render the inner
detail, complex tonalities, and elaborate harmonic structures produced by acoustic
So out came a parade of acoustic challenges. In the Tuba
Mirum of Mozarts Requiem, as performed by Sir Charles Mackerras and the
Scottish Chamber Orchestra (CD, Linn CDK 211), the opening trombone displayed remarkably
good pitch definition and texture, and astounding resonance. "Poem of Chinese
Drum," from Yim Hok-Mans Master of Chinese Percussion (HDCD, Lim K2HD
033), had low-level clarity and coherence as well as window-rattling depth. The string
bass on Jorma Kaukonens Blue Country Heart (SACD/CD, Columbia CS 86394) was
tight, with no sign of overhang.
This is not to say that I cant think of a number of
speakers that provide comparable low-end performance. But its the Xs
extraordinary realization of the midrange and highs that draw the masses.
Throughout the Mozart Requiem, the Summit X rendered
the voices of soprano Susan Gritton, mezzo-soprano Catherine Wyn-Rogers, and tenor Timothy
Robinson with silkiness and immediacy. Even the voices of individual members of the
Scottish Chamber Chorus were exposed. "The Sweetest Taboo," from The Best of
Sade (CD, Epic EK 66686), presented Sades voice with a sublime warmth and
delicacy that highlighted her sultry, erotic phrasing. Numerous tracks from Shirley
Horns You Wont Forget Me (CD, Verve 847 482-2) unmasked
heretofore hidden inflections of voice that would impress even her casual fans. Indeed,
time after time, the Xes delivered voices that were more detailed, open, and colorless
than Id previously heard in my listening room.
A midrange of this quality would be enough for some
speakers to call it a day. But for the Summit X, such skill did not come at the expense of
top-end performance. Instead, everything from percussion to bowed instruments was marked
by a distinctively clean airiness. The playful opening cymbal strokes in Steely Dans
"Deacon Blues," from A Decade of Steely Dan (CD, MCA MCAD-11553), threw a
bewildering amount of microdynamic data at the Xes that they deftly sorted through,
disclosing subtleties of the initial impact of stick on cymbal that are often lost among
the ringing waves of energized brass. The Xes also masterfully reproduced the resulting
delicate sheen that hovered almost weightlessly over the soundstage, ending only when the
last metallic reverberation had been revealed. The protracted, ultra-high-frequency
"money notes" in Catalanis "Ebben? . . . Ne andrņ lontana,"
from Galina Gorchakovas Italian Opera Arias, with conductor Constantine
Orbelian and the Russian Philharmonic (SACD, Delos DS 3286), were spine-chilling, and so
extended theyd no doubt unnerve all but the very best dynamic tweeters.
I heard no sharp, screechy, or collapsed highs, or
upper-level grain or harshness, from the Summit X -- unless such defects were present on
the recording. Indeed, the X picked up not only everything on each of my recordings, but
also any extraneous noise generated by my electronics. Accordingly, a high-quality,
low-noise amplifier and well-recorded source material are absolutely essential.
Other strengths of the Summit X were in dynamic range,
soundstaging, and transient delivery. The dynamic range was often startling and
didnt seem the least bit constrained, as some claim can occur with curved
electrostatic panels. The Xes mammoth soundstage can be described only as
"electrostatic"-large, and contained focused images that rooted themselves deep
beyond my rooms front wall. On several occasions I closed my eyes and pointed to the
locations of the various instruments that I was hearing. When I then opened my eyes, I
often found myself pointing not at the speakers, but at some other place in the
soundstage. Transient speed was so fast as to render useless any comparison to speakers
with dynamic drivers.
But the perfect speaker has yet to be made. One area of the
Summit X that could be improved is its off-axis performance. MartinLogan says that the
Xes limited sweet spot is the unavoidable byproduct of a design choice that, as
indicated above, controls dispersion by focusing radiated sound into a limited horizontal
path. Nonetheless, I found that, for optimal tonality, detail, and imaging, I would be
disinclined to invite more than one other person to join me for a serious listening
session -- and even that might be pushing it, unless we occasionally traded seats.
However, I found that the farther I sat from the Summit Xes, the larger the sweet spot
was, with only marginal tradeoffs in detail and tone.
And while Ill opt for transparency and finesse over
brute force any day of the week, the Summit X lacked the sheer weight that some of the
larger dynamic-driver speakers can bring to the upper bass and midrange. The strings in
the Mozart Requiem were exquisite -- silky, detailed, and surrounded by what seemed
physically measurable gobs of air. The Xes also artfully exposed the leading transient
edges of each pizzicato pluck. However, the MLs didnt possess the inner density
Ive heard from the meatiest dynamic speakers. You say you want a Ferrari that can
accommodate your family of seven and your dog?
Comparison: V and S vs. X
I compared the Summit X to MartinLogans own Vantage.
At $5695/pair, the Vantage is more speaker than most listeners will ever need.
Nonetheless, in moving up to the Summit X, the moneyed audiophile will experience weighty
gains in just about every audiophile criterion, not least of which is musicality. Buyers
of the X should know that its far less forgiving than the Vantage, in part because
its more revealing. That the X is better than the Vantage shouldnt surprise --
at two-and-a-half times the price, it should be.
Far more intriguing to me was to compare the Summit X with
the model it replaces -- the Summit itself ($9995/pair), a speaker Id considered
buying a few years ago, until financial reality set in. While preparing to write this
review, I visited a friend who has a pair of Summits in order to refresh my recollections
of their sound.
Right off the bat I realized that, in the Xs high and
midrange regions, MartinLogan has made great strides. The X sounded immensely more lush,
airy, and open than the Summit. The Xes also presented more detail and a larger, more
solid soundstage. In fact, above the crossover point, the X seemed to produce a
substantial reworking of the Summits sound, which was somewhat more cool and
closed-in, more dull and removed.
I found the bass performances of the X and Summit to be
more or less on a par. Well, not exactly -- the Summits low-level detail, extension,
and accuracy turned out to be very comparable to that of the X, but the X handily
outperformed the Summit in the integration of the outputs of the woofers and electrostatic
According to MartinLogan, their Vojtko crossover tightly
aligns the phase at the crossover point, thus providing dispersion in the low end that, as
with the output of the electrostatic panel, minimizes sidewall reflections. The Summit X
woofers are thus said to operate more like the panels than in previous ML models,
resulting in a more seamless transition to the upper bass.
Regardless of how the Vojtko crossover works, the improved
integration of the drivers outputs is a significant accomplishment. While
theres still room for improvement, the blend in the Summit X is much smoother than
in the Summit. Of course, as stated above, the perfect speaker does not exist; the art of
speaker design always entails making the best selection among many compromises.
Conclusion: electrostatic Xuberance
The Summit X is the latest step in MartinLogans
ongoing quest for electrostatic perfection. Theyve improved on the technologys
stunning strengths -- transparency, speed, immediacy, midrange presence, soundstaging --
while minimizing its shortcomings, particularly in the integration of the outputs of the
woofers and upper-range panels. When these speakers make their special magic, theyll
likely astound and emotionally move even the most experienced and hardened audiophile.
I find the Summit X just too addictive to live without.
Im putting my money where my mouth is and buying the review pair to serve as my new
reference loudspeakers. I may never reach the promised land of Audio Nirvana,
electrostatic or otherwise, but thanks to MartinLogan, Im going to enjoy the
. . . Howard Kneller
|MartinLogan Summit X Loudspeakers
Price: $13,995 USD per pair.
Warranty: Five years parts and labor.
Lawrence, KS 66046
Phone: (785) 749-0133
Fax: (785) 749-5320