MartinLogan EM-ESL C Owner's Manual

user’s manual

®

WARNING! Do not use your
EM-ESL C loudspeakers outside of
the country of original sale—voltage
requirements vary by country. Improper voltage can
cause damage that will be potentially expensive
to repair. The EM-ESL C is shipped to authorized
MartinLogan distributors with the correct power
supply for use in the country of intended sale. A list
of authorized distributors can be accessed at www.
martinlogan.com or by e-mailing info@martinlogan.

The lightning bolt flash with arrowhead
symbol, within an equilateral triangle,

is intended to alert the user to the
presence of potentially “dangerous voltage” within the
product’s enclosure that may be sufficient to constitute
a risk of electric shock.

The exclamation point within an
equilateral triangle is intended to alert

the user to the presence of important
operating and maintenance (servicing) instructions in
the literature accompanying the appliance.

In accordance with the European Union
WEEE (Waste Electrical and Electronic
Equipment) directive effective August 13,

2005, we would like to notify you that
this product may contain regulated materials which
upon disposal, according to the WEEE directive,
require special reuse and recycling processing.
For this reason Martin Logan has arranged with our
distributors in European Union member nations to
collect and recycle this product at no cost to you.

Installation in Brief .....................4

Introduction ..........................5

Connections .........................6

Low-Voltage (DC) Power Connection .......6

Speaker Level Conneciton ..............6

Installation ..........................7

Break-In ..........................7

Installing on a Flat Surface .............7

Vertical Dispersion ...................7

Home Theater ........................7

Electrostatic Advantages ................9

MartinLogan Exclusives ................10

CLS™ (Curvilinear Line Source) .........10

XStat Transducer ...................10

MicroPerf Stator ...................10

Vacuum Bonding ...................10

Folded Motion™ Tweeter .............10

Electrostatic History ...................11

Frequently Asked Questions .............13

Troubleshooting ......................15

General Information ..................16

Warranty and Registration ............16

Serial Number ....................16

Service .........................16

Specifications .......................17

Glossary of Audio Terms ...............17

Dimensional Drawings .................20

To find your local distributor contact the dealer from whom
you purchased this product, email [e-mail]
or visit the distributor locator at www.martinlogan.com.

Please note, only this product itself falls under the
WEEE directive. When disposing of packaging and
other related shipping materials we encourage you to
recycle these items through the normal channels.

2

Serial Number:_____________________________

x 1

Record your serial number here for easy reference. You will need this information when filling out your
warranty registration. The serial number is located near the binding posts and on the product carton.

3

WARNING! Do not use your EM-ESL C loudspeakers outside of the country of
original sale—voltage requirements vary by country. Improper voltage can cause
damage that will be potentially expensive to repair. The EM-ESL C is shipped to
authorized MartinLogan distributors with the correct power supply for use in the
country of intended sale. A list of authorized distributors can be accessed at www.
martinlogan.com or by emailing [e-mail].

InstallatIon In BrIef

We know you are eager to hear your new
ElectroMotion ESL C (EM-ESL C) speakers, so this
section is provided to allow fast and easy set up.
Once you have them operational, please take the
time to read, in depth, the rest of the information in
this manual. It will give you perspective on how to
attain the greatest possible performance from this
most exacting transducer.

If you should experience any difficulties in the setup
or operation of your EM-ESL C speakers, please
refer to the Room Acoustics, Placement or Operation
sections of this manual. Should you encounter a
persistent problem that cannot be resolved, please
contact your authorized MartinLogan dealer. They
will provide you with the appropriate technical anal­ysis to alleviate the situation.

WARNING!

• Hazardous voltages exist
inside—do not remove cover.

• Refer servicing to a qualified
technician.

• To prevent fire or shock hazard, do not
expose this module to moisture.

• Turn amplifier off and unplug speaker
should any abnormal conditions occur.

• Turn amplifier off before making or
breaking any signal connections!

• Do not operate if there is any visual
damage to the electrostatic panel element.

• Do not drive speaker beyond its rated power.

• The power cord should not be installed,
removed, or left detached from the speaker
while the other end is connected to an AC
power source.

• No candles or other sources of open flame
should be placed on the speaker.

• No liquids either in glasses or vases should
be placed on speaker.

• Speaker should not be exposed to dripping
or splashing liquids.

• The terminals marked with the lightning bolt
symbol should be connected by an instructed
person or by way of ready made terminals.

Step 1: Unpacking

Remove your new EM-ESL C speaker from the
packaging.

Step 2: Placement

Place the EM-ESL C at your desired location and
and angle the stat panel towards your listening
area. Please see the Placement section of this
manual for more details.

Step 3: Power Connection (see warning)

Your EM-ESL C speaker requires power to energize
the electrostatic cells. Using the power cord
provided, plug it in first to the power receptacle
on the rear panel of the speaker, making sure that
you have made a firm connection, and then to a
wall outlet. Please see Low-Voltage (DC) Power
Connection for more details.

4

Step 4: Signal Connection

Use the best speaker cables you can. Higher
quality cables, available from your specialty
dealer, are recommended and will give you
superior performance.

Attach your speaker cables to the signal input
section on the rear panel. Be consistent when
connecting speaker leads to the terminals on the
back of the EM-ESL C.

IntroductIon

For detailed setup instructions, please turn to the
Speaker Level Connection section of this manual
for more details.

Step 5: Listen and Enjoy

Now, you may turn on your system and enjoy!

Congratulations! You have invested in one of the
world’s premier speaker systems.

The ElectroMotion ESL C (EM-ESL C) represents
an advanced combination of sonic technologies
establishing an unprecedented direction for
audiophile design. The result of years of research,
the new EM-ESL C hybrid electrostatic loudspeaker
delivers new standards for efficiency, dynamics
and precision in a floor standing loudspeaker.

The EM-ESL C’s CLS XStat™ transducer builds
upon the legacy of MartinLogan’s electrostatic
heritage with the incorporation of advanced
vacuum bonding and MicroPerf stat panels,
providing even greater efficiency and precision.
The integration electrical interface technology
developed by MartinLogan’s CLX engineering
team extends effortless dynamics and purity,
resulting in even higher sonic standards of
efficiency and precision.

Featuring an advanced crossover topology,
MartinLogan carefully builds each EM-ESL C
crossover utilizing precision components to
flawlessly preserve sonic subtleties while effortlessly
handling the broadest range of dynamics

contained within even the most demanding sonic
source.

The materials in your new EM-ESL C speakers are
of the highest quality and will provide years of
enduring enjoyment and deepening respect. The
cabinetry is constructed from the highest quality
composite material for acoustical integrity.

Through rigorous testing, the curvilinear electrostatic
panel has proven itself to be one of the most
durable and reliable transducers available today.
Fabricated from a custom tool punched high-grade
steel, the patented panel is then coated with a
special polymer that is applied via a proprietary
electrostatic bonding process. This panel assembly
houses a membrane just 0.0005 of an inch thick.

The other sections of your User’s Manual explain
in detail the operation of your EM-ESL C speakers
and the philosophy applied to their design. A clear
understanding of your speakers will insure that you
obtain maximum performance and pleasure from
this most exacting transducer. It has been designed
and constructed to give you years of trouble-free
listening enjoyment.

5

connectIons

LOW-VOLTAGE (DC) POWER CONNECTION

Your EM-ESL C speakers use external low-voltage
power supplies to energize their electrostatic pan­els. For this reason the proper low-voltage power
supplies are provided. A power supply should be
firmly inserted into the ‘DC Power In’ receptacle on
the rear connection panel of each speaker, then
to any convenient AC wall outlet. Your EM-ESL C
speakers integrate a signal sensing circuit which will
switch the EM-ESL C off after a few minutes of no
music signal, and requires less than two seconds to
recharge the panels when a music signal is present.

Your EM-ESL C speakers are provided with a power
supply for the power service supplied in the country
of original consumer sale. The AC power require-

Fig. 1

Fig. 2

ments applicable to a particular unit is specified both
on the packing carton and on the DC power supply.

If you remove your EM-ESL C speakers from the
country of original sale, be certain that the AC
power supplied in any subsequent location is suit­able before connecting the low-voltage power
supply. Substantially impaired performance or
severe damage may occur to a EM-ESL C speaker
if operation is attempted from an incorrect AC
power source.

WARNING! The DC power
supply should not be installed,
removed, or left detached from
the speaker while connected to an
AC power source.

SPEAKER LEVEL CONNECTION

Use the best speaker cables you can. The length
and type of speaker cable used in your system will
have an audible effect. Under no circumstance
should a wire of gauge higher (thinner) than #16
be used. In general, the longer the length used,
the greater the necessity of a lower gauge, and
the lower the gauge, the better the sound, with
diminishing returns setting in around #8 to #12.

A variety of cables are available whose manufactur­ers claim better performance than standard heavy
gauge wire. We have verified this in many cases,
and the improvements available are often more
noticeable than the differences between wires of dif­ferent gauge. The effects of cables may be masked
if equipment is not of the highest quality.

Connections are done at the signal input section
on the rear electronics panel of the speaker. Use
spade connectors for optimum contact and ease
of installation. Hand tighten the binding posts, but

6

do not overtighten—do not use a tool to tighten the
binding posts.

Be consistent when connecting the speaker cables
to the signal input terminals. Take care to assign
the same color cable lead to the (+) terminal on

InstallatIon

both the left and right channel speakers. If bass is
nonexistent and you cannot discern a tight, coher­ent image, you may need to reverse the (+) and
(–) leads on one speaker to bring the system into
proper polarity.

WARNING! Installation other
than that described in the body of
this document requires specific
documentation from MartinLogan.

BREAK IN

Allow approximately 72 hours of break-in at 90 dB
(moderate listening levels) before critical listening.

Fig. 3

INSTALLING ON A FLAT SURFACE

If you have a surface that provides a wide, level,
and stable platform, the speaker can be placed
directly on top. Note: This speaker is not magneti­cally shielded and therefore should not be placed
directly beside or atop a CRT television.

VERTICAL DISPERSION

For optimal performance, the Folded Motion tweet­er and electrostatic panel should be aimed in the
direction of your ears when sitting in your primary
listening position. The bottom of the speaker fea­tures an adjustable foot that allows the speaker to
be easily aimed.

When this speaker is installed on a low surface,
leave the adjustable foot flush with the bottom of
the speaker so the electrostatic panel and Folded
Motion tweeter aims slightly upward.

If your speaker is installed near or slightly below
ear height, extend the adjustable foot so the elec­trostatic panel and Folded Motion tweeter are
vertical.

Home tHeater

It had long been the practice of stereo buffs to
connect their television to a stereo system. The
advantage was the use of the larger speakers and
more powerful amplifier of the stereo system. Even
though the sound was greatly improved, it was still

mono and limited by the broadcast signal.

In the late 1970’s and early 1980’s two new
home movie formats became widely available to
the public: VCR and laser disc.

7

By 1985, both formats had developed into very
high quality audio/video sources. In fact, the sonic
performance of some video formats exceeded
audio-only formats. Now, with theater-quality
sound available at home, the only element missing
was the “surround sound” presentation found in
movie houses.

Fortunately, Dolby and DTS encoded DVD’s
emerged with the same surround sound
information encoded on home releases as the
theatrical release. Additionally, new high­resolution home-viewing formats such as Blu-ray
as well as high-definition content provided via
cable or satellite have evolved which include multi­channel encoded audio that is virtually master
tape quality. All that is required to retrieve this
information is a decoder and additional speakers
and amps to reproduce it.

Home theater is a complex purchase and we
recommend that you consult your local MartinLogan
dealer, as they are well versed in this subject.

Each piece of a surround system can be purchased
separately. Take your time and buy quality. No
one has ever complained that the movie was too
real. The following list and descriptions will give
you only a brief outline of the responsibilities and
demands placed on each speaker.

that the center speaker be extremely accurate and
mate well with the front speaker, and that it is
recommended for use as a center speaker. This is
not the place to cut corners.

Surround Speakers

We recommend (along with the film industry) that
the surround speakers play down to at least 80
Hz. Surround speakers contain the information that
makes it appear that planes are flying over your
head. Some may suggest that this is the place
to save money and purchase small, inexpensive
speakers. If you choose to do so, be prepared
to upgrade in the future as discrete multi-channel
digital encoding is proliferating rapidly and the
demands on surround speakers have increased.

Subwoofer

With any good surround system you will need
high-quality subwoofers (the .1 in a 5.1, 6.1,
or 7.1 channel surround system). Most movie
soundtracks contain large amounts of bass
information as part of the special effects. Good
subwoofers will provide a foundation for the rest
of the system.

Front Left and Front Right

If these speakers will be the same two used for
your stereo playback, they should be of very high
quality and able to play loudly (over 102 dB) and
reproduce bass below 80 Hz.

Center Channel

This is the most important speaker in a home
theater system, as almost all of the dialogue and
a large portion of the front speaker information is
reproduced by the center channel. It is important

8

Figure 4. MartinLogan peakers as front, center, and
surround channels, and MartinLogan subwoofers in the
front corners as the 0.1 (effects) channel.

electrostatIc advantages

How can sound be reproduced by something that
you are able to see through? Electrostatic energy
makes this possible. Where the world of traditional
loudspeaker technology deals with cones, domes,
diaphragms and ribbons that are moved with
magnetism, the world of electrostatic loudspeakers
deals with charged electrons attracting and
repelling each other.

To fully understand the electrostatic concept, some
background information will be helpful. Remember
when you learned in a science or physics class
that like charges repel each other and opposite
charges attract each other? Well, this principle is
the foundation of the electrostatic concept.

An electrostatic transducer consists of three
pieces: stators, the diaphragm and spacers. The
diaphragm is what actually moves to excite the
air and create music. The stator’s job is to remain
stationary, hence the word stator, and to provide
a reference point for the moving diaphragm.
The spacers provide the diaphragm with a fixed
distance in which to move between the stators.

As your amplifier sends music signals to an
electrostatic speaker, these signals are changed
into two high-voltage signals that are equal in
strength but opposite in polarity. These high
voltage signals are then applied to the stators.
The resulting electrostatic field, created by the
opposing high voltage on the stators, works
simultaneously with and against the diaphragm,
consequently moving it back and forth, producing
music. This technique is known as push-pull
operation and is a major contributor to the sonic
purity of the electrostatic concept due to its
exceptional linearity and low distortion.

Since the diaphragm of an electrostatic speaker
is uniformly driven over its entire area, it can be

extremely light and flexible. This allows it to be very
responsive to transients, thus perfectly tracing the
music signal. As a result, great delicacy, nuance and
clarity is possible. When you look at the problems
of traditional electromagnetic drivers, you can easily
see why this is so beneficial. The cones and domes
which are used in traditional electromagnetic drivers

Figure 5. Cut away view of an electrostatic
transducer. Notice the simplicity due to minimal
parts usage.

Figure 6. Cut away view of a typical moving
coil driver. Notice the complexity due to the high
number of parts.

9

cannot be driven uniformly because of their design.
Cones are driven only at the apex. Domes are driven
at their perimeter. As a result, the rest of the cone or
dome is just “along for the ride”. The very concept
of these drivers requires that the cone or dome be
perfectly rigid, damped and massless. Unfortunately,
these conditions are not available in our world today.

To make these cones and domes move, all
electromagnetic drivers must use voice coils wound

martInlogan exclusIves

on formers, spider assemblies, and surrounds to
keep the cone or dome in position. These pieces,
when combined with the high mass of the cone
or dome materials used, make it an extremely
complex unit with many weaknesses and potential
for failure. These faults contribute to the high
distortion products found in these drivers and is a
tremendous disadvantage when you are trying to
change motion as quickly and as accurately as a
loudspeaker must (40,000 times per second!).

CLS™ (CURVILINEAR LINE SOURCE)

Since the beginning of audio, achieving smooth dis­persion has been a problem for all designers. Large
panel transducers present unique challenge because
the larger the panel, the more directional the disper­sion pattern becomes. Wide range electrostats have
long been one of the most problematic transducers
because they attain their full range capabilities via
a large surface area. It looked as if they were in
direct conflict to smooth dispersion and almost every
attempt to correct this resulted in either poor disper­sion or a serious compromise in sound quality.

After extensive research, MartinLogan engineers
discovered an elegantly simple solution to achieve
a smooth pattern of dispersion without degrading
sound quality. By curving the horizontal plane of
the electrostatic transducer, a controlled horizontal
dispersion pattern could be achieved, yet the purity of
the almost massless electrostatic diaphragm remained
uncompromised. After creating this technology,
MartinLogan developed the production capability
to bring it out of the laboratory and into the market
place. You will find this proprietary MartinLogan
technology used in all of our electrostatic products.
It is one of the many reasons behind our reputation
for high quality sound with practical usability. This is
also why you see the unique “see through” cylindrical
shape of MartinLogan products.

XSTAT™ TRANSDUCER

XStat™ transducers incorporate a myriad of
technology and design innovations including
CLS™, MicroPerf, Generation 2 Diaphragms,
ClearSpars™, and Vacuum Bonding.

MICROPERF STATOR

Sleek. Compact. MicroPerf stator technology,
featured in EM-ESL C’s electrostatic transducer, reveals
more open playable area in each panel, offering
increased performance from even more compact stat
panels. It is significant to note that the electrostatic
transducer in the radical new EM-ESL C loudspeaker
supports the bandwidth and dynamics associated with
traditional electrostatic panels nearly twice its size.

VACUUM BONDING

To achieve the power, precision, and strength of
the electrostatic transducer, two insulated high­purity carbon steel stators along with a proprietary
plasma bonded diaphragm and ClearSpar™
spacers are fused into a curved geometry with an
aerospace adhesive whose strength exceeds that of
welding. Our proprietary Vacuum Bonding process
guarantees uniform diaphragm tensioning and
extremely precise construction tolerances, resulting
in unequivocal precision, linearity and efficiency.

10

FOLDED MOTION™ TWEETER

The Folded Motion Tweeter works by moving air
(which creates sound) perpendicular to the folded
ridges of the diaphragm, similar to how an accor­dion works. This extremely low mass diaphragm
“squeezes” air and requires almost 90% less

electrostatIc HIstory

excursion than the typical 1” dome tweeter, which
drastically minimizes distortion while providing a
lightning fast response time. The increased surface
area also provides a wide, yet controlled sound
dispersion to create a realistic and carefully etched
sound stage.

In the late 1800’s, any loudspeaker was considered
exotic. Today, most of us take the wonders of sound
reproduction for granted.

It was 1880 before Thomas Edison had invented
the first phonograph. This was a horn-loaded
diaphragm that was excited by a playback
stylus. In 1898, Sir Oliver Lodge invented a
cone loudspeaker, which he referred to as a
“bellowing telephone”, that was very similar to
the conventional cone loudspeaker drivers that we
know today. However, Lodge had no intention for
his device to reproduce music because in 1898
there was no way to amplify an electrical signal!
As a result, his speaker had nothing to offer over
the acoustical gramophones of the period. It was
not until 1906 that Dr. Lee DeForrest invented the
triode vacuum tube. Before this, an electrical signal
could not be amplified. The loudspeaker, as we
know it today, should have ensued then, but it did
not. Amazingly, it was almost twenty years before
this would occur.

In 1921, the electrically cut phonograph record
became a reality. This method of recording was
far superior to the mechanically cut record and
possessed almost 30 dB of dynamic range.
The acoustical gramophone couldn’t begin to
reproduce all of the information on this new disc.
As a result, further developments in loudspeakers
were needed to cope with this amazing new
recording medium.

By 1923, the decision to develop a complete
musical playback system consisting of an electronic
phonograph and a loudspeaker to take advantage
of the new recording medium – the project of two
young engineers, C. W. Rice and E. W. Kellogg.

Rice and Kellogg had a well equipped laboratory
at their disposal. This lab possessed a vacuum
tube amplifier with an unheard of 200 watts,
a large selection of the new electrically cut
phonograph records and a variety of loudspeaker
prototypes collecting over the past decade.
Among these were Lodge’s cone, a speaker that
used compressed air, a corona discharge (plasma)
speaker, and an electrostatic speaker.

After a short time, Rice and Kellogg had narrowed
the field of “contestants” down to the cone
and the electrostat. The outcome would dictate
the way that future generations would refer to
loudspeakers as being either “conventional”
or “exotic”.

Rice and Kellogg’s electrostat was something
to behold. This enormous bipolar speaker was
as big as a door. The diaphragm, which was
beginning to rot, was made of a pig intestine that
was covered with fine gold leaf to conduct the
audio signal.

When Rice and Kellogg began playing the new
electrically cut records through the electrostat,
they were stunned and impressed. The electrostat

11

performed splendidly. They had never heard
instrumental timbres reproduced with such realism.
This system sounded like real music rather than
the honking, squawking rendition of the acoustic
gramophone. Immediately, they knew they were
on to something big. The acoustic gramophone
was destined to become obsolete.

Due to Rice and Kellogg’s enthusiasm, they
devoted a considerable amount of time
researching the electrostatic design. However,
they soon encountered the same difficulties that
even present designers face; planar speakers
require a very large surface area to reproduce
the lower frequencies of the audio spectrum.
Because the management considered large
speakers unacceptable, Rice and Kellogg’s work
on electrostatics would never be put to use for a
commercial product. Reluctantly, they advised the
management to go with the cone. For the next 30
years, the electrostatic design lay dormant.

During the Great Depression of the 1930’s,
consumer audio almost died. The new electrically
amplified loudspeaker never gained acceptance,
as most people continued to use their old Victrola­style acoustic gramophones. Prior to the end of
World War II, consumer audio saw little, if any,
progress. However, during the late 1940’s,
audio experienced a great rebirth. Suddenly there
was tremendous interest in audio products, and
with that, a great demand for improved audio
components. No sooner had the cone become
established than it was challenged by products
developed during this new rebirth.

In 1947, Arthur Janszen, a young Naval engineer,
took part in a research project for the Navy.
The Navy was interested in developing a better
instrument for testing microphone arrays. The test
instrument needed an extremely accurate speaker,
but Janszen found that the cone speakers of the
period were too nonlinear in phase and amplitude

response to meet his criteria. Janszen believed
that electrostats were inherently more linear than
cones, so he built a model using a thin plastic
diaphragm treated with a conductive coating. This
model confirmed Janszen’s beliefs, for it exhibited
remarkable phase and amplitude linearity.

Janszen was so excited with the results that he
continued research on the electrostatic speaker
on his own time. He soon thought of insulating the
stators to prevent the destructive effects of arcing.
By 1952, he had an electrostatic tweeter element
ready for commercial production. This new tweeter
soon created a sensation among American audio
hobbyists. Since Janszen’s tweeter element was
limited to high frequency reproduction, it often
found itself used in conjunction with woofers—
most notably, those from Acoustic Research.
These systems were highly regarded by all audio
enthusiasts.

As good as these systems were, they would soon
be surpassed by another electrostatic speaker.

In 1955, Peter Walker published three articles
regarding electrostatic loudspeaker design in
Wireless World, a British magazine. In these
articles, Walker demonstrated the benefits of
the electrostatic loudspeaker. He explained that
electrostatics permit the use of diaphragms that
are low in mass, large in area and uniformly
driven over their surfaces by electrostatic forces.
Due to these characteristics, electrostats have the
inherent ability to produce a wide bandwidth, flat
frequency response with distortion products being
no greater than the electronics driving them.

By 1956, Walker backed up his articles by
introducing a consumer product, the now famous
Quad ESL. This speaker immediately set a
standard of performance for the audio industry
due to its incredible accuracy. However, in actual
use, the Quad had a few problems. It could not be

12