The Expression ESL 13A is part of the Masterpiece Series. It features
a dual 10-inch woofer system with ARC-honed performance, for perfectly
blended low-frequency response. The groundbreaking integration of this
woofer array with MartinLogan’s signature 13-inch wide XStat CLS
Transducer, coupled with a powerful dual amplifier section, delivers an
expressive and dynamic audio experience, with less coloration. It
reveals the pure emotional impact of your audio.
Using two 10-inch laser-engineered low-distortion aluminum cone
woofers in independently enclosed compact chambers, exclusive
PoweredForce Forward™ bass alignment technology controls the interaction
between the rear-firing woofer and the wall behind that woofer. With
smart phase-shifting logic, we minimize the effect that wall has on bass
information that might bounce back into the listening room. This
uniform frequency response results in realistic bass effects you can
feel. It’s one more way MartinLogan innovation improves your listening
experience in any room.
Achieving the Laboratory Standard in Your Own Room
In the lab, MartinLogan engineers strive for transparency. Outside
the lab, there’s one wildcard our engineers can never account for: Your
listening room. The unique size and shape of your listening space (and
the size and shape of its contents) can make bass waves do unpredictable
things, greatly affecting a speaker’s overall performance.
The Expression ESL 13A integrates exclusive Anthem Room Correction
(ARC) technology. By engaging ARC to control the low-frequency curve in
relation to the output of the ESL panel (as seen in this graph), you
will experience performance on par with MartinLogan’s audio test lab.
ARC measures low-frequency sound output in your room and compares it
to optimal response curves that account for spatial anomalies. The
advanced algorithms of ARC then effectively remove the anomalies,
leaving only the ideal standard: realistically blended, natural-sounding
bass performance in your listening space.
By minimizing room interactions with PoweredForce Forward bass
technology and the advanced room correction capabilities of ARC, along
with its unique synthesis of the ESL and bass sections, the Expression
ESL 13A produces perfectly-etched imaging and focus; optimum natural
reproduction of sound at lifelike listening levels; and agile,
full-range operation in open air.
Clearly, it is this level of ultimate performance that separates the merely excellent from a true masterpiece.
New Ultra-Rigid AirFrame Blade Design
Expression ESL 13A XStat panels are joined to their speaker cabinets using MartinLogan’s redesigned AirFrame Blade
construction, precision manufactured from an aerospace-grade extruded
aluminum alloy. This material, and this exclusive manufacturing process,
makes the panels extremely rigid.
The bold, forward-moving styling of this AirFrame Blade
rail system, narrow and strong in front, broad and forceful from the
side, is a modern design statement. It never obstructs playable surface
area or interferes with the panel’s dipole sound radiation pattern. It
also provides electrical and acoustical isolation, minimizing
intermodulation distortion caused by vibration and resonance. The
flowing lines emphasize the groundbreaking integration of the panel
itself with the compact woofer and amplifier section. The breathtaking
AirFrame Blade design enhances imaging, low-level sonic detail, accuracy, and speaker efficiency.
Curvilinear Line Source (CLS) Electrostatic Panel
CLS technology is an essential ingredient of every electrostatic
loudspeaker we produce. Through our proprietary manufacturing method, we
have built-in the panel’s gentle horizontal curvature. This unique
design enhances the high frequency detail produced by the large
radiating surface, without compromising overall sound quality. Notice
how the gentle modern curve and perforation pattern gives way to the
flat grille of the woofer section.
Controlled Dispersion Sound Radiation
The sound we hear from a loudspeaker is a combination of direct
radiation from it to our ears, and reflections off of room
surfaces—walls, floor, and ceiling. How our brains integrate this
information is far from simple. Depending on the angle of incidence to
the ears and the arrival-time difference between direct and reflected
sound, reflections can either blur detail and stereo imaging, or enhance
the natural impression of depth and openness.
Electrostatic panels, which are true dipole speakers, produce a
nearly-ideal controlled dispersion radiation pattern. They send very
little sound to the sides, thereby minimizing side-wall reflections,
whose short arrival times tend to interfere with the perception of the
direct sound. Their strong rear radiation, however, produces a generous
amount of natural, ambience-enriching later-arriving mid- and upper
New PoweredForce Forward™ Bass Technology
PoweredForce Forward bass technology combines two MartinLogan audio
innovations: PoweredForce, which allows small enclosures to accurately
produce massive amounts of bass, and ForceForward, which significantly
reduces performance-robbing front-wall bass reflections.
PoweredForce Forward bass technology uses an advanced crossover
topology with phase-timed woofers to minimize destructive reflected
energy. By virtually eliminating front-wall bass reflections and working
in tandem with the panel, PoweredForce Forward Bass Technology gives
you more placement flexibility, and enhances the true audio realism of
your sound source.
Turning Unused Space Into Better Bass
The depth of Masterpiece Series speaker cabinets was carefully chosen to maximize benefits of both PoweredForce and ForceForward technologies, providing powerful bass with extreme detail. Combined with Anthem Room Correction (ARC™), these advanced bass technologies provide a level of low-frequency precision that is truly unique.
Masterpiece Series speaker cabinet dimensions create an ideal
relationship between the woofers, cabinet volume, and amplifiers in
their PoweredForce woofer systems. By providing ample internal
volume for the woofers (two sealed enclosures—one per woofer) along with
powerful amplification, Masterpiece Series speakers with powered woofer
systems are capable of reaching the lowest registers with authority
while preserving bass detail.
With ForceForward bass technology, the farther apart the
woofers are from each other the lower in frequency its beneficial
effects extend. MartinLogan’s ForceForward technology has
solved a problem (found in nearly all speakers) where low bass frequency
soundwaves reflect off the wall behind the speakers and interact with
the waves traveling towards the listener. These interactions create
non-linearity in those frequencies as they arrive at your ears and bass
information suffers from both cancelations and excessiveness that is not
accurate to the original sound. By selectively adjusting phasing of
output from their opposing woofers, powered Masterpiece Series speakers
eliminate problematic bass energy from behind the speakers.
ForceForward also simplifies the task of speaker placement
by removing bass energy from behind the speaker and creating a uniform
bass launch. This allows Masterpiece Series speaker cabinets to go
closer to the wall than previous generations of MartinLogan speakers. As
a rule of thumb we recommend placing the rear of the speaker cabinet no
closer to the wall than the diameter of its woofer (Renaissance ESL
15A: 12-inches, Expression ESL 13A: 10-inches, and Impression ESL 11A
and Classic ESL 9: 8-inches). For an added level of control powered
Masterpiece Series speakers incorporate two level controls (at 75Hz and
200Hz) to allow for fine tuning of bass integration.
Additionally, due to their dipole nature, electrostatic panels
perform best when placed at least 2.5-feet or more from the wall—a
distance that is ideal for the front of nearly any high-end speaker,
regardless of driver technology. The depth of Masterpiece Series
cabinets lends itself to providing electrostatic panels with adequate
distance from the wall, guaranteeing a richly detailed,
New More Performance, Versatility, and Safety, with WBT Binding Posts
Connect your electronics safely and securely using 5-Way audiophile
WBT Binding Posts. Their pure copper connection plate is highly
conductive and free from “eddy current” effects. These posts are
insulated for shock protection, and fully damped against vibrations.
They give you plenty of room for large-gauge professional speaker
New Powerful Dual 300-Watt Class-D Amplification with 24-Bit Vojtko™ DSP Engine
The performance of Expression ESL 13A has been reconsidered from the
ground up. Taking full advantage of innovations like PoweredForce
Forward and ARC Technology, and the integration of the electrostatic
panel with the woofer array, required daring thinking about power and
efficiency. Our new dual 300-watt amplifiers produce clean power, in a
small space, more efficiently than ever before. They enable the
effortless delivery of exhilarating dynamic impact, with plenty of
overhead. Superior, reliable Class-D technology means there’s virtually
no energy lost between the amplifiers and the woofers.
MartinLogan’s dedicated in-house design and engineering team created an
extremely precise 24-bit Vojtko Digital Signal Processing (DSP) engine
to work in conjunction with these powerful new amplifiers. It gives
these speakers the ability to deliver detailed low-frequency performance
reaching down to 22Hz. Advanced DSP allows complete control and
performance optimization over the low pass filters, woofer equalization
and limiting functions, all of which are mapped mathematically in the
digital domain. Complete control of the signal, along with instant
response, huge amounts of clean power, and efficient, integrated
performance, paints an original picture of lifelike audio performance.
Precision-Built Advanced-Topology Vojtko Crossover
Vojtko Voiced, the advanced crossover and electronics in Expression
ESL 13A add enhanced mid-range clarity to this artful composition.
Carefully hand-built using only the finest polypropylene capacitors and
air-core coils, the crossover employs MartinLogan’s proprietary Vojtko
topology for vanishingly low distortion and seamless driver/ESL
integration. This precision-tuned network preserves even the most
microscopic sonic nuances while handling the full dynamics of any
We’ve also considered the signal you will feed your loudspeakers, and
have engineered Expression ESL 13A to work well with practically any
type of electronics. MartinLogan’s state-of-the-art toroidal transformer
and electrical interface engineering ensure an absolutely transparent
link from amplifier to electrostatic panel and woofer array. This
produces sound of unparalleled purity, precision, clarity, and openness —
the next best thing to no speaker at all.