Martin Logan Logos Owners manual
User's Manual
The Logos Center Channel
Important
Contents
Your Logos
Limited 90 Day Warranty coverage.
You have the option, at no additional charge, to receive
Limited 3 Year Warranty coverage. To obtain Limited 3
Year Warranty coverage you need only complete and
return the Certificate of Registration that was included
with your speaker along with a copy of your invoice to
Martin-Logan, within 30 days of purchase.
Martin-Logan may not honor warranty serviceMartin-Logan may not honor warranty service
Martin-Logan may not honor warranty service
Martin-Logan may not honor warranty serviceMartin-Logan may not honor warranty service
claims unless we have a completed Warrantyclaims unless we have a completed Warranty
claims unless we have a completed Warranty
claims unless we have a completed Warrantyclaims unless we have a completed Warranty
Registration card on file!Registration card on file!
Registration card on file!
Registration card on file!Registration card on file!
Should you be using your Martin-Logan product in a
country other than the one in which it was originally
purchased, we ask that you note the following:
1) The appointed Martin-Logan distributor for any given
country is responsible for warranty servicing only on
units distributed by or through it in that country in
accordance with its applicable warranty.
2) Should a Martin-Logan product require servicing in a
country other than the one in which it was originally
purchased, the end user may seek to have repairs
performed by the nearest Martin-Logan distributor,
subject to that distributor's local servicing policies,
but all cost of repairs (parts, labor, transportation)
must be born by the owner of the Martin-Logan
product.
3) If you relocate to another country, other than where
you purchased your Martin-Logan product, after
owning your speakers for 6 months your warranty
may be transferable. Contact Martin-Logan for
details.
If you did not receive a Certificate of Registration with
your Logos
received a new unit. If this is the case, please contact
your Authorized Martin-Logan dealer.
speaker is provided with an automatic
speaker you cannot be assured of having
Introduction 3
History 4
The Electrostatic Concept 6
Martin-Logan Exclusives 7
Installation Options 8
Operation 9
Logos Bracket Assembly/Setup 1 0
Room Acoustics 1 2
Dispersion Characteristics 1 4
Home Theatre 1 5
Questions 1 6
Troubleshooting 1 7
Glossary 1 8
Page 2
Logos Specifications 2 0
Logos User's Manual
Introduction
Congratulations, you have invested in the world's first
electrostatic hybrid home theatre speaker!
The advantages of Martin-Logan hybrid technology will
present themselves to you from moment the movie
begins. The box effect (a phenomenon similar to cupping
your hands around your mouth when speaking) produced
by dynamic midrange drivers is absent and the natural
openness of the human voice comes through. Never
before in home theatre has the midrange been so clear.
Sounds float around the screen clearly defining the area
from where they were created, not the area of the
speaker that created them. This superior performance is
made possible through the use of our proprietary curved
electrostatic transducer. This is the same design technology that is used in the state-of-the-art Martin-Logan
Loudspeaker Systems.
All materials in your new Logos speaker are of the
highest quality to provide years of enduring enjoyment
and deepening respect. The cabinetry is constructed from
a special high-density hardwood powderboard for
structural integrity and is finished with a durable and
attractive matte surface finish.
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
specially tooled, high-grade steel, the panel is then
coated with a special high dielectric compound that is
applied via a proprietary electrostatic deposition process.
This panel assembly houses a membrane 0.0005 of an
inch thick! Ruggedly constructed and insulated, as much
as 200 watts of continuous power has driven the Logos
energized diaphragm into massive excursions with no
deleterious effects.
Please read and follow these instructions as you initially
install the Logos
important and will prevent you from experiencing any
delay, frustration, or system damage which might occur in
a trial-and-error procedure.
The other sections of your
detail the operation of your Logos
philosophy applied to its design. A clear understanding of
your speaker will insure that you obtain maximum
performance and pleasure from this most exacting
transducer.
Happy Listening!
into your system. These instructions are
User’s Manual User’s Manual
User’s Manual will explain in
User’s Manual User’s Manual
speaker and the
Logos User's Manual
Page 3
History
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, Bell Telephone Laboratories made the decision
to develop a complete musical playback system consisting of an electronic phonograph and loudspeaker to take
advantage of the new recording medium. Bell Labs
assigned the project to 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 that Bell Labs had been 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".
Bell Laboratory’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 the
membrane of a pigs 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
shocked and impressed. The electrostat 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 at Bell Labs 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 Bell management to go with
the cone. For the next thirty 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 Victrola-style 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.
Page 4
Logos User's Manual
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, woofers from Acoustic Research. These systems
were highly regarded by all audio enthusiasts.
presented a difficult load that some amplifiers did not like,
its dispersion was very directional, and its power handling was limited to around 70 watts. As a result, many
people continued to use box speakers with cones.
In the early 1960's Arthur Janszen joined forces with the
KLH loudspeaker company and together they introduced
the KLH 9. Due to the large size of the KLH 9, it did not
have as many limitations as the Quad. The KLH 9 could
play markedly louder and lower in frequency than the
Quad ESL. Thus a rivalry was born.
Janszen continued to develop electrostatic designs. He
was instrumental in the design of the Koss Model One,
the Acoustech, and the Dennesen speakers. Roger West,
the chief designer of the JansZen Corporation became
the president of Sound Lab. When JansZen Corporation
was sold, the RTR loudspeaker company bought half of
the production tooling. This tooling was used to make the
electrostatic panels for the Servostatic, a hybrid electrostatic system that was Infinity's first speaker product. Other
companies soon followed; each with their own unique
applications of the technology. These include Acoustat,
Audiostatic, Beverage, Dayton Wright, Sound Lab, and
Stax to name a few.
As good as these systems were, they would soon be
surpassed by another electrostatic speaker.
In 1955, Peter Walker published three articles on
electrostatic loudspeaker design in
Wireless World
, a
British electronics 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 play very loud, it had poor bass performance, it
Logos User's Manual
Electrostatic speakers have progressed and prospered
because they actually do what Peter Walker claimed they
would. The limitations and problems experienced in the
past were not inherent to the electrostatic concept. They
were related to the applications of these concepts.
Today, these limitations have been addressed. Advancements in materials due to the U.S. space program give
designers the ability to harness the superiority of the
electrostatic principle. Today's electrostats use advanced
insulation techniques or provide protection circuitry. The
poor dispersion properties of early models have been
addressed by using delay lines, acoustical lenses,
multiple panel arrays or, as in our own products, by
curving the diaphragm. Power handling and sensitivity
have been increased.
These developments allow the consumer the opportunity
to own the highest performance loudspeaker products
ever built. It's too bad Rice and Kellogg were never able
to see just how far the technology would be taken.
Page 5
The Electrostatic Concept
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
An Electrostatic TransducerAn Electrostatic Transducer
An Electrostatic Transducer
An Electrostatic TransducerAn Electrostatic Transducer
foundation of the electrostatic
concept.
An electrostatic transducer
consists of three pieces: the
stators, the diaphragm and the
spacers.
See Figure 1
. The
Diaphragm
Spacer
diaphragm is what actually
moves to excite the air and
create music. The stator's job is
to remain stationary, hence the
word stator, to provide a
reference point for the moving
diaphragm. The spacers
provide the diaphragm with a
Figure 1Figure 1
Figure 1. Cut away view of an electrostatic transducer.
Figure 1Figure 1
Notice the simplicity due to minimal parts usage.
fixed distance in which to move
between the stators.
An Electromagnetic TransducerAn Electromagnetic Transducer
An Electromagnetic Transducer
An Electromagnetic TransducerAn Electromagnetic Transducer
As your amplifier sends music
signals to an electrostatic
Surround
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
Basket Assembly
Magnet
simultaneously with and against
the diaphragm, consequently
moving it back and forth,
producing music. This tech-
Figure 2.Figure 2.
Figure 2. Cut away view of a typical moving coil driver.
Figure 2.Figure 2.
Notice the complexity due to the high number of parts.
Cone
nique 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 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 require that the cone
or dome be perfectly rigid,
Stator
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 on formers,
spider assemblies, and
surrounds to keep the cone
See
Dust Cap
Voice Coil Former
or dome in position.
Figure 2.
These pieces, when
combined with the high mass
of the cone or dome materials used, make it an extremely complex unit with
Spider
many weaknesses and
potential for failure. These
faults contribute to the high
distortion products found in
Magnet Assembly
Magnetic GapVoice Coil
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!).
Page 6
Logos User's Manual
Martin-Logan Exclusives
Vapor Deposited FilmVapor Deposited Film
Vapor Deposited Film
Vapor Deposited FilmVapor Deposited Film
The diaphragm material used in all Martin-Logan
speakers employs an extremely sophisticated vapor
deposited conductive polymer membrane. A
proprietary conductive compound is vaporized then
electrostatically driven into the surface of the
polymer film in a vacuum chamber. This process
allows an optically transparent membrane, adds no
mass to the diaphragm and is extremely uniform in its
surface resistivity characteristics. This uniform surface
resistivity controls the electrostatic charge on the
diaphragm surface and regulates its migration. As a
result, no discharging or “arcing” can occur.
Transducer IntegrityTransducer Integrity
Transducer Integrity
Transducer IntegrityTransducer Integrity
All Martin-Logan transducers begin with two pieces
of high grade, cold rolled steel. These steel pieces
are then custom perforated and insulated with an
exotic composite coating. This proprietary coating
insulates the stator to 3 times its actual needed
working voltage and gives the Logos a wide margin
of safe operation. In addition to the electrical
insulation properties, this coating also provides the
Logos with a durable, attractive finish that dampens
the steel to prevent ringing. The finished metal plates
are curved into a 30 degree arc. Placed between
them is our exclusive vapor deposited diaphragm
and spacers. This assembly is then bonded together
with aerospace adhesives whose strength is so great
that it is commonly used as an alternative to welding.
The result of these advanced technologies is a
transducer that is attractive, durable, highly rigid, well
dampened, and neutral.
Mechanical/AcousticalMechanical/Acoustical
Mechanical/Acoustical
Mechanical/AcousticalMechanical/Acoustical Tone ShapingTone Shaping
Tone Shaping
Tone ShapingTone Shaping
The clear Lexan® panels on the back of the Logos stator
are the key elements of an innovative pressure compen-
sation technology. Martin-Logan is able to tone-shape the
diaphragm + or - 6dB without the use of an insertion loss
crossover. The advantage of this system is a high
efficiency driver with wide bandwidth capabilities of
dimensions which are easily integrated into a domestic
environment.
Curvilinear Line SourceCurvilinear Line Source
Curvilinear Line Source
Curvilinear Line SourceCurvilinear Line Source
Since the beginning of audio, achieving smooth full
range dispersion has long been a problem for all
loudspeaker designers. Large panel transducers
present even more of a challenge because the
larger the panel, the more directional the dispersion
pattern becomes.
Full range electrostatics have always been one of
the most complex 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, Martin-Logan 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, we developed the production capability to
bring this technology out of the laboratory and into
the market place.
You will find this proprietary Martin-Logan technology
used in all of our 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 all MartinLogan products.
Logos User's Manual
Page 7
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