MartinLogan Purity User Manual

TM

P URITY

Fully Powered Hybrid Electrostatic Loudspeaker

user’s manual

Thank you—to you the MartinLogan owner,

for loving what we do,

and

for making it possible for us to do what we love.

Serial Numbers: _______________ / _______________

Record your serial numbers here for easy reference. You will need this
information when filling out your warranty registration. Purity’s serial num­ber is located near the bottom of the backplate and on the shipping
container. Each individual unit has a unique serial number.

Purity

Tested to Comply

with FCC Standards

FOR HOME OR OFFICE USE

This device complies with part 15 of
the FCC Rules. Operation is subject
to the following two conditions: (1)
This device may not cause harmful
interference, and (2) this device must
accept any interference received,
including interference that may cause
undesired operation.

CONTENTS

Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

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

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

Connections & Controls . . . . . . . . . . . . . . . . 6

AC Power Connection
Status Light
Line Level (RCA) Connection

Speaker Level Connection . . . . . . . . . . . . . . . . . . . .7

Bass Level Control
Break-In

Placement & Room Acoustics . . . . . . . . . . . . 8

Listening Position
The Wall Behind the Listener
The Wall Behind the Speakers
The Side Walls
Experimentation

Final Placement . . . . . . . . . . . . . . . . . . . . . . . . . . 9

The Extra “Tweak” . . . . . . . . . . . . . . . . . . . . . . . 10

Your Room
Terminology

Rules of Thumb . . . . . . . . . . . . . . . . . . . . . . . . . .11

Dipolar Speakers and Your Room
Solid Footing

Dispersion Interactions . . . . . . . . . . . . . . . . 12

Controlled Horizontal Dispersion
Controlled Vertical Dispersion
Three Major Types of Dispersion

Home Theater . . . . . . . . . . . . . . . . . . . . . . 13

Electrostatic Advantages . . . . . . . . . . . . . . 14

MartinLogan Exclusives . . . . . . . . . . . . . . . 15

Full Range Operation

CLS™ (Curvilinear Line Source) . . . . . . . . . . . . . . .16

Generation 2 Diaphragm
MicroPerf Stator

Vacuum Bonding
AirFrame™ Technology

Electrostatic Loudspeaker History . . . . . . . . 17

Frequently Asked Questions. . . . . . . . . . . . 19

Troubleshooting . . . . . . . . . . . . . . . . . . . . . 21

General Information . . . . . . . . . . . . . . . . . 22

Specifications
Warranty and Registration
Serial Number
Service

Dimensional Drawings . . . . . . . . . . . . . . . . 23

Glossary of Audio Terms . . . . . . . . . . . . . . 24

Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

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 MartinLogan has arranged with our
distributors in European Union member nations to collect
and recycle this product at no cost to you. To find your
local distributor please 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.

The lightning bolt flash with arrowhead symbol, within

an equilateral triangle, is intended to alert the user to
the presence of uninsulated “dangerous voltage” within
the product’s enclosure that may be of sufficient magni­tude 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.

WARNING! Do not use your Purity 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 Purity 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 info@martinlogan.

Contents 3

INSTALLATION IN BRIEF

We know you are eager to hear your Purity 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 Purity 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 Purity speakers from their packaging.

Step 2: Placement

Place each Purity at least two feet from the back wall and
angle them slightly toward your listening area. This is a
good place to start. Please see the Placement section
(pages 8–11) of this manual for more details.

Step 3: Power Connection (AC) (see warning)

Your Purity speakers require AC power to energize their
electrostatic cells and internal amplifiers. Using the AC
power cords provided,
receptacle on the rear panel of the speaker
that you have made a firm
outlet. Please see AC Power Connection (pages 6) for more
details.

Step 4: Signal Connection

Attach your speakers using either the Line Level input or the
Speaker Level input on the rear panel of your speakers.

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

When using the Speaker Level inputs be consistent when
connecting speaker leads to the terminals on the back of
the Purity speakers. Take great care to assign the same
color to the (+) terminal on both the left and right chan­nels. If bass is nonexistent and you cannot discern a tight,
coherent image, you may need to reverse the (+) and
(–) leads on one side to bring the system into proper polar­ity. Spade connectors are suggested for optimum contact
and ease of installation.

For detailed setup instructions, please turn to the
Connections and Controls section (Page 6–7) of this man­ual for more details.

Step 5: Listen and Enjoy

Now, you may turn on your system and enjoy!

plug them in

connection, and then to a wall

first to the AC power

, making sure

4 Installation in Brief

INTRODUCTION

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

Internally powered with a high-resolution digital ampli­fier, the Purity provides an unprecedented level of system
connection flexibility. Equipped with a standard line-level
input, the Purity is able to connect directly to devices such
as digital music players, flat screen televisions or even
computers. Additional speaker level inputs also allow
Purity to exist in a more traditional receiver or pre-amp
equipped 2-channel or home theater system.

The MartinLogan Purity represents an advanced combina­tion of sonic technologies establishing an unprecedented
direction for audiophile design. The result of years of
research, the new Purity hybrid electrostatic loudspeaker
delivers new standards for efficiency, dynamics and preci­sion in a floorstanding loudspeaker.

Housed within a radical, ultra-rigid extruded aluminum
AirFrame™, the Purity’s CLS 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 Statement™ e2 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 Purity crossover utilizing precision
audiophile-grade components to preserves sonic subtleties
while effortlessly handling the broadest range of dynamics
contained within even the most demanding sonic source.

The materials in your new Purity 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 Purity 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.

Introduction 5

CONNECTIONS & CONTROLS

AC Power Connection

Because your Purity speakers use an internal power supply
to energize their electrostatic cells and to power the inter­nal amplifiers, they must be connected to an AC power
source. For this reason they are provided with the proper
IEC standard power cords. These cords should be firmly
inserted into the AC power receptacles on the rear con­nection panel of the speakers, then to any convenient AC
wall outlet (see figure 2 & 3). The Purity’s integrate a signal
sensing power supply which will switch off after five min­utes of no music signal, and requires less than two seconds
to recharge the panels when a music signal is present.

Your Purity speakers are wired for the power ser­vice supplied in the country of original consumer sale.
The AC power requirements applicable to a particu­lar unit is specified both on the packing carton and
on the serial number plate attached to the speaker.
If you remove your Purity speakers from the country
of original sale, be certain that the AC power supplied in
any subsequent location is suitable before connecting and
operating the speakers. Substantially impaired performance
or severe damage may occur to an Purity speaker if opera­tion is attempted from an incorrect AC power source.

WARNING! 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.

When using the Line Level connection do not use
the Speaker Level connections at the same time.

Use Purity’s line level connection to attach any of the follow­ing devices (see figure 1):

• Television

• Computer

• Digital Music Player or docking station

• Receiver / Pre-Amp (using pre-amp outputs)

Connection is achieved by connecting an RCA cable from
the output on the device to the Line Level input on the Purity.
If your output device is not equipped with an RCA style
output connector we recommend using a 3.5mm stereo
headphone to dual RCA connector (available at nearly any
electronics retailer).

When using Purity’s Line Level Input, make sure that the out­put device’s connection utilizes a variable level control (i.e.

Status Light

Behind and near the bottom of the stat panel is a status
light. This light notates the following operation modes:

• Blue: The speaker is active and ready to play.

• Red: The speaker is in auto standby mode.

• Flashing Red: The speaker is in auto-protect mode.

This may occur if the internal amplifier overheats. To
reset the speaker unplug it for 10 seconds. This also

occurs if the speaker is being used with an incompat­ible AC voltage (i.e. outside country of original sale).

• Short Red Flash: This will occur when the speaker is

plugged into or unplugged from an AC power source.

6 Connections & Controls

volume control). Usually this is a headphone or pre-amp
output. However, as this varies from device to device we
recommend referencing your device’s user manual.

Please note: When making or breaking connections
from devices that utilize the Line Level input a popping
noise may occur. This is caused by grounding and static
discharge interaction. It is normal and to be expected when
using this method of connection. If a cable is connected to
the speaker, but is left unterminated at the device end you
may also experience a low-level hum. To minimize these
intermittent noises we recommend using a device that is per­manently connected (such as a digital music player docking
station).

Speaker Level Connection

When using the Speaker Level connections do not
use the Line Level connection at the same time.

Use spade connectors for optimum contact and ease of
installation. Hand tighten the binding posts, but do not
overtighten—do not use a tool to tighten the binding posts
(see figure 2).

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 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.

Please note: When using the speaker level inputs a
popping noise may occur when the amplifier is turned on
or off. This is caused by grounding interaction between the
speaker and the amplifier. It is normal and to be expected.
The Purity features a built in muting circuit that will detect
such anomalies and minimize them.

WARNING! Turn your amplifier off
before making or breaking any signal con­nections!

Bass Level Control

On the rear panel of the Purity electronics module
position Bass Level
of low frequency response you desire.

The flat position is considered the normal setting for most
rooms. However, if you feel that the bass in your system
is too light or heavy relative to the mid and high frequen­cies,

simply select the +3dB or –3dB position to adjust the

woofer output.

Some experimentation with these switch settings will allow
you to find the optimal tonal balance for your specific taste,
room and equipment.

switch that allows you to select the type

is a three

Break-In

When you begin to play your speakers, they will sound
a bit bass shy. This is due to the high quality, long-life
components used in our woofers. Our custom made, butyl
surround woofer requires approximately 72 hours of break­in at 90 dB (moderate listening levels) before any critical
listening. The break-in requirements of the crossover com­ponents and the electrostatic stator are equivalent.

Connections & Controls 7

PLACEMENT & ROOM ACOUSTICS

Listening Position

Your speakers should be placed approximately two to
three feet from the front wall, the wall in front of the lis­tening position, and about two feet from the side walls.
Your sitting distance should be further than the distance
between the speakers themselves. You are trying to attain
the impression of good center imaging and stage width.

There is no exact distance between speakers and listener,
but there is a relationship. In long rooms, naturally, that
relationship changes. The distance between the speakers
will be far less than the distance from you to the speaker
system. However, in a wide room, you will still find that
if the distance from the listener to the speakers becomes
smaller than the distance between the speakers themselves,
the image will no longer focus in the center.

Now that you have positioned your speaker system, spend
time listening. Wait to make any major changes in
setup for the next few days as the speaker
change subtly in its sound. Over the first 72 hours of play the
actual tonal quality will change slightly with deeper bass and
more spacious highs resulting. After a few days of listening
you can begin to make refinements and hear the differ­ences.

your initial

system itself will

The Wall Behind the Listener

The front surface ideally should be one long wall without
any doors or openings. If you have openings, the reflection
and bass characteristics from each channel can be different.

The Side Walls

A good rule of thumb is to have the side walls as far away
from the speaker sides as possible. However, MartinLogan’s
unique controlled dispersion electrostatic transducer inher­ently minimizes side wall reflections—a position as little
as two feet from the side walls often proves adequate.
Sometimes, if the system is bright or the imaging is not to
your liking, and the side walls are very near, try putting
curtains or softening material directly to the edge of each
speaker. An ideal side wall, however, is no side wall at all.

Experimentation

Toe-in

Now you can begin to experiment. First begin by toeing
your speakers in towards the listening area and then fac­ing them straight into the room. You will notice the tonal
balance and imaging changing. You will notice that as the
speakers are toed-out, the system becomes slightly bright­er than when toed-in. This design gives you the flexibility
to compensate for a soft or bright room.

Near-field reflections can also occur from your back wall (the
wall behind the listening position). If your listening position
is close to the back wall, these reflections can cause prob­lems and confuse imaging quality. It is better for the wall
behind you to be absorptive than to be reflective. If you
have a hard back wall and your listening position is close to
it, experiment with devices that will absorb information (i.e.
wall hangings and possibly even sound absorbing panels).

The Wall Behind the Speakers

The front surface, the wall behind the speakers, should
not be extremely hard or soft. A pane of glass will cause
reflections, brightness and confused imaging. Curtains,
drapery and objects such as bookshelves can be placed
along the wall to diffuse an overly reflective surface. A
standard sheet rock or textured wall is generally an ade­quate surface if the rest of the room is not too bright and
hard. Walls can also be too soft. If the entire front wall
consists of heavy drapery, your system can sound dull.
You may hear muted music with little ambience. Harder
surfaces will actually help in this case.

Generally it is found that the ideal listening position is with
the speakers slightly toed-in so that you are listening to the
inner third of the curved transducer section. A simple, yet
effective method to achieve proper toe involves sitting at the
listening position, holding a flashlight under your chin and
pointing it at each speaker. The reflection of the flashlight
should be within the inner third of the panel (see figure 3).

8 Placement & Room Acoustics

Tilting the Speakers Backwards and Forwards

As the diagrams show in the Dispersion Interactions sec­tion of this manual (page 12), the vertical dispersion is
directional above and below the stator panel itself. In
some instances, if you are sitting close to the floor, slight
forward tilting of the speakers can enhance clarity and
precision. Tilt can be adjusted by adjusting the MiniETC
spikes (see page 11).

12° of tilt beyond the standard 1°. Experimenting with
increased tilt may yield a superior listening experience.

1 Turn off you amplifier. Unplug the speakers and discon-

nect all wires from the back of the Purity.

2 Using a blanket to protect Purity’s cabinet, place the

speaker on its side.

Your Purity loudspeaker also is equipped with a pivoting
base which allows the speaker to achieve an additional

3 Loosen and remove the hand nut on bottom of the

speaker.

4 Remove the base, rotate it, and replace it.

5 Re-attach the hand nut.

Imaging

In their final location, your Purity’s can have a stage
width somewhat wider than the speakers themselves.
On well recorded music, the instruments can extend
beyond the edges of each speaker (left and right), yet
a vocalist should appear directly in the middle. The size of the
instruments should be neither too large nor too small, subject
to the intent and results of each unique audio recording.

Additionally, you should find good clues as to stage
depth. Make sure that the vertical alignment, distance from
the front wall, and toe-in is exactly the same for both speakers.
This will greatly enhance the quality of your imaging.

Bass Response

Your bass response should neither be one note nor
should it be too heavy. It should extend to the deep­est organ passages and yet be tight and well defined.
Kick-drums should be tight and percussive—string
bass notes should be uniform and consistent through­out the entirety of the run without booming or thudding.

Tonal Balance

Voices should be natural and full and cymbals
should be detailed and articulate yet not bright and
piercing, pianos should have a nice transient characteristic
and deep tonal registers. This will give you clues on how to
get closer to these ideal virtues.

Final Placement

After the full break in period, obtaining good wall treat­ments, and the proper toe-in angle, begin to experiment
with the distance from the wall behind the speakers. Move

Placement & Room Acoustics 9

your speaker slightly forward into the room. What hap­pened to the bass response? What happened to the
imaging? If the imaging is more open and spacious and
the bass response is tightened, that is a superior posi­tion. Move the speakers back six inches from the initial
setup position and again listen to the imaging and bass
response. There will be a position where you will have pin­point imaging and good bass response. That position is
the point of the optimal placement from the front wall.

Now experiment with placing the speakers farther apart.
As the speakers are positioned farther apart, listen again,
not so much for bass response but for stage width and
good pinpoint focusing. Your ideal listening position and
speaker position will be determined by:

of your system. It can dramatically add to, or subtract
from, a great musical experience.

All sound is composed of waves. Each note has its own
wave size, with the lower bass notes literally encompassing
from 10’ feet to as much as 40’ feet. Your room partici­pates in this wave experience like a three dimensional pool
with waves reflecting and becoming enhanced depending
on the size of the room and the types of surfaces in the room.
Remember, your audio system can literally generate all of
the information required to recreate a musical event in time,
space, and tonal balance. Ideally, your room should not
contribute to that information. However, every room does con­tribute to the sound to some degree. Fortunately MartinLogan
had designed the Purity to minimize these anomalies

• Tightness and extension of bass response

• Width of the stage

• Pinpoint focusing of imaging

Once you have determined the best of all three of these
considerations, you will have your best speaker location.

The Extra “Tweak”

This extra “tweak” may be useful when your speakers are
placed in a dedicated listening room. Use the following
procedure and measurements for your speakers placement
to see what can happen to your system’s performance.
These formulas will help determine optimum placement of
your speakers to minimize standing waves.

1 Distance from the front wall (in front of the listening

position) to the center of the curvilinear transducer: To
determine distance from the front wall, measure the
ceiling height (inches) and multiply the figure by 0.618
(i.e. ceiling height (inches) x 0.618 = the distance from
the front wall to the center of the curvilinear transducer).

2 Distance from the side-walls to the center of the curvi-

linear transducer: To determine distance from the side
walls, measure the width of your room in inches and
divide by 18. Next, multiply the quotient by 5 (i.e.
room width in inches / 18 x 5 = the distance from the
side-walls to the center of the curvilinear transducer).

Your Room

This is one of those areas that requires both a little back­ground to understand and some time and experimentation
to obtain the best performance from your system.
Your room is actually a component and an important part

Terminology

Standing Waves

The parallel walls in your room will reinforce certain notes
to the point that they will sound louder than the rest of
the audio spectrum and cause “one note bass”, “boomy
bass” or “bloated bass”. For instance, 100Hz represents a
10 feet wavelength. Your room will reinforce that specific
frequency if one of the dominant dimensions is 10 feet.
Large objects in the room such as cabinetry or furniture
can help to minimize this potential problem. Some serious
“audiophiles” will literally build a special room with no
parallel walls just to help eliminate this phenomenon.

Reflective Surfaces (near-field reflections)

The hard surfaces of your room, particularly if close to your
speaker system, will reflect some waves back into the room
over and over again, confusing the clarity and imaging of
your system. The smaller sound waves are mostly affected
here, and occur in the mid and high frequencies. This is
where voice and frequencies as high as the cymbals occur.

Resonant Surfaces and Objects

All of the surfaces and objects in your room are subject to
the frequencies generated by your system. Much like an
instrument, they will vibrate and “carry on” in syncopation
with the music, and contribute in a negative way to the
music. Ringing, boominess, and even brightness can occur
simply because they are “singing along” with your music.

Resonant Cavities

Small alcoves or closet type areas in your room can be
chambers that create their own “standing waves” and can
drum their own “one note” sounds.
Clap your hands. Can you hear an instant echo respond

10 Placement & Room Acoustics

back? You have near-field reflections. Stomp your foot.
Can you hear a “boom”? You have standing waves or
large panel resonances such as a poorly supported wall.
Put your head in a small cavity area and talk loudly. Hear
a booming? You’ve just experienced a cavity resonance.

Rules of Thumb

Hard vs. Soft Surfaces

If the front or back wall of your listening room is soft, it
might benefit you to have a hard or reflective wall in
opposition. The ceiling and floor should follow the same
basic guideline as well. However, the side walls should be
roughly the same in order to deliver a focused image.

This rule suggests that a little reflection is good. As a matter
of fact, some rooms can be so “over damped” with carpet­ing, drapes and sound absorbers that the music system
can sound dull and lifeless. On the other hand, rooms can
be so hard that the system can sound like a gymnasium
with too much reflection and brightness. The point is that bal­ance is the optimum environment.

Breakup Objects

Objects with complex shapes, such as bookshelves, cabinetry
and multiple shaped walls can help break up those sonic
gremlins and diffuse any dominant frequencies.

ing. Consequently the result is blurred imaging and excessive
brightness. Soft walls, curtains, wall hangings, or sound
dampeners (your dealer can give you good information here)
can be effective if these negative conditions occur.

Solid Footing

After living and experimenting with your Purity speakers, you
may want to use ETC (energy transfer coupler) Spikes (see
figure 7), which are available from your local MartinLogan
dealer or from the Xtatic shop at www.martinlogan.com.
With the use of these spikes, the Purity will become more
firmly planted on the floor and, consequently, bass will tight­en and imaging will become more coherent and detailed.
It is best not to implement the spikes, however, until you are
secure in the positioning, as the spikes can damage the
floor if the speaker is moved. MartinLogan ETC spikes will
fit any common 1/4” x 20 thread insert that may be found
on your other audio equipment (racks, etc.)

Spike Installation Instructions:

1 Carefully place your speaker on its side.

2 Remove existing feet. Thread new spikes into holes

and screw them in all of the way. If the speaker does
not sit level loosen one spike until level is achieved.

Dipolar Speakers and Your Room

MartinLogan electrostatic loudspeakers are known as dipo­lar radiators. This means that they produce sound from
both their fronts and their backs. Consequently, musical
information is reflected by the wall behind them and may
arrive, either in or out of step, with the information pro­duced by the front of the speaker.

The low frequencies can either be enhanced or nulled by the
position from the front wall. Your Purity’s have been designed
to be placed two to three feet from the front wall (the wall in
front of the listening position) to obtain the best results; how­ever, your room may see things differently. So listening to the
difference of the bass response as a result of the changes
in distance from the front wall can allow you to get the best
combination of depth of bass and tonal balance.

Now that you know about reflective surfaces and resonant
objects, you can see how the midrange and high frequen­cies can be affected. The timing of the initial wave as it
radiates to your ears, and then the reflected information as
it arrives at your ears later in time, can result in confusion of
the precious timing information that carries the clues to imag-

3 Tighten the jam nut snugly by hand. Do not over tighten.

4 Right the speaker.

Caution: Make sure your hands and any cabling are

clear of the spikes. Do not slide speaker as spikes are
sharp and can damage your floor or carpet.

5 Adjust to level by rotating spikes. Tighten the jam nut

securely when satisfied that speaker is level. Caution:
Walking the speaker may result in a broken spike.

Figure 7. The ETC Spike.

Placement & Room Acoustics 11

DISPERSION INTERACTIONS

Three Major Types of Dispersion

Your Purity’s launch a 30 degree horizontal dispersion pat­tern. This horizontal dispersion field gives a choice of good
seats for the performance while minimizing interactions with
side walls (see figure 12). Make sure both speakers stand
exactly at the same vertical angle, otherwise the image can
be skewed or poorly defined. The wave launch of both
speakers is extremely accurate in both the time and spectral
domain. Consequently, small refined adjustments can result
in noticeable sonic improvements.

Controlled Vertical Dispersion

As you can see from the illustrations, your Purity speakers
project a controlled dispersion pattern (see figure 13). Each
Purity is a 28 inch line source beginning 24 inches above
the base. This vertical dispersion profile minimizes interac­tions with the floor and the ceiling.

Figure 8–9. As can be seen here, point
source concepts invite a great deal of room
interaction. While delivering good frequency
response to a large listening audience, imaging
is consequently confused and blurred.

It is a known fact that as the sound wave becomes pro­gressively smaller than the transducer producing it,
the dispersion of that wave becomes more and more
narrow, or directional. This fact occurs as long as the
transducer is a flat surface. Large flat panel speakers
exhibit venetian blind effects due to this phenomenon.
This is one reason why many manufacturers opt for small
drivers (i.e. tweeters and midrange) to approximate
what is known as a point source wave launch.

Historically, most attempts to achieve smooth dispersion
from large flat panel transducers resulted in trade-offs.
After exhaustive testing of many different methods, we
conceived an elegantly simple, yet intensely hand craft­ed process. By curving the radiating surface, we create
the effect of a horizontal arc. This allows the engineers at
MartinLogan to control the high frequency dispersion pat­tern of our transducers.

Figure 10–11. Even though they suffer from
“venetian blind” effect, angled multiple panel
speakers can deliver good imaging, but only
to specific spots in the listening area.

Figure 12–13. A controlled 30 degree cylin­drical wave-front, a MartinLogan exclusive,
offers optimal sound distribution with minimal
room interaction. The result is solid imaging
with a wide listening area.

12 Dispersion Interactions

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.

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
high-resolution home-viewing formats such as HD-DVD
and Blu-ray as well as high-definition content provided via
cable or satellite have evolved which include multi-channel
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.

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 one or
more 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.

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.

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 that the center speaker be
extremely accurate and mate well with the front speaker,

Figure 14. Purity speakers as front channels, Vignette speakers above
the television and along the back wall as the center and surround (effects)
channels, and Dynamo subwoofers in the front corners as the 0.1 (effects)
channel.

Home Theater 13

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 (see figure 15). 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 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 on formers, spider
assemblies, and surrounds to keep the cone or dome in
position (see figure 16). 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!).

Figure 15. Cut away view of an electrostatic transducer. Notice the
simplicity due to minimal parts usage.

14 Electrostatic Advantages

Full Range Operation

Another significant advantage of MartinLogan’s exclusive
transducer technology reveals itself when you look at exam­ples of other loudspeaker products on the market today.

The Purity uses no crossover networks above 450 Hz
because they are not needed. The Purity consists of a single,
seamless electrostatic membrane reproducing all frequen­cies above 450 Hz simultaneously. How is this possible?

First we must understand that music is not composed of
separate high, mid and low frequency pieces. In fact,
music is comprised of a single complex waveform with all
frequencies interacting simultaneously.

The electrostatic transducer of the Purity essentially acts
as an exact opposite of the microphones used to record
the original event. A microphone, which is a single work­ing element, transforms acoustic energy into an electrical
signal that can be amplified or preserved by some type
of storage media. The Purity’s electrostatic transducer
transforms electrical energy from your amplifier back into
acoustical energy.

Due to the limitations of electromagnetic drivers, no single
unit can reproduce the full range of frequencies. Instead,
these drivers must be designed to operate within a nar-

row, fixed bandwidth of the frequency range, and then
combined electrically so that the sum of the parts equals
the total signal. While nice in theory, we must deal with
real-world conditions.

In order to use multiple drivers, a crossover network
is enlisted to attempt a division of the complex musical
signal into the separate pieces (usually highs, mids, and
lows) that each specific driver was designed to handle.
Unfortunately, due to the phase relationships that occur
within all crossover networks and during the acoustical
recombination process, nonlinearities and severe degra­dation of the music signal take place in the ear’s most
critical zone (see figure 17).

The Purity’s electrostatic transducer can single-handedly
reproduce all frequencies above 450 Hz simultaneously.
You have in one transducer the ability to handle in elegant
simplicity the critical frequencies above 450 Hz.

The crossover phase aberrations that are associated with
traditional tweeter, midrange, and woofer systems are
eliminated. The result is a dramatic improvement in imag­ing and staging performance due to the minutely accurate
phase relationship of the full-range panel wave launch.

MartinLogan Exclusives 15

CLS™ (Curvilinear Line Source)

MicroPerf Stator

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.

Generation 2 Diaphragm

Purity’s diaphragm employs an extremely sophisticated
conductive coating applied to the polymer surface at an
atomic level using a plasma bonding process. A propri­etary compound is driven into the surface of the polymer
film in an oxygen free argon chamber. This process
allows extremely uniform surface resistivity characteristics,
an optically transparent surface, and a nearly massless
diaphragm. 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.

Sleek. Compact. MicroPerf stator technology, featured in
Purity’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
Purity 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 high-purity 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.

AirFrame™ Technology

Ultra-rigid extruded aerospace grade aluminum alloy
AirFrame™ technology rigidifies and secures the elec­trostatic panel to the woofer cabinet while at the same
time providing sonic and electrical isolation. Advanced
AirFrame™ technology maximizes the electrostatic pan­els playable surface area and dipole dispersion pattern
while minimizing potentially acoustically destructive
intermodulated distortion caused by spurious vibrations
and resonance. The result? Ultimate imaging capability,
low-level detail resolution, improved efficiency and overall
accuracy.

16 MartinLogan Exclusives

ELECTROSTATIC 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 a 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
ma) speaker, and an electrostatic speaker.

that used compressed air, a corona discharge (plas-

Rice and Kellogg had

narrowed the field of

“contestants down” to the

cone and the electrostat.

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 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 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
Kellogg’s
for a commercial product. Reluctantly, they advised the Bell
management to go with the cone. For the next 30 years,
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.

work on electrostatics would never be put to use

unacceptable, Rice and

the

Electrostatic History 17

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
od were too nonlinear in phase and amplitude response
meet his criteria. Janszen believed that electrostats were inher­ently more linear than cones, so he built a
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 played
very loud, it had poor bass performance, it presented a dif­ficult load that some amplifiers did not like, its dispersion

model

using a thin

These developments allow

the consumer to own the

highest performance loud-

speaker products ever built.

peri-

to

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 sonic 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.
Corporation was
loudspeaker company bought
half of the production tooling. This
tooling was used to make the
trostatic panels for the Servostatic, a

hybrid electrostatic
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.

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 resolved. 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 also 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.

When Janszen
sold, the RTR

elec-

system that was

18 Electrostatic History

FREQUENTLY ASKED QUESTIONS

How do I clean my speakers?

Use a dust free cloth or a soft brush to remove the dust
from your speakers. We also recommend a specialty
cloth (available at the Xtatic shop at www.martinlogan.
com) that cleans your speakers better than anything else
we have tried. For the wood surfaces it is acceptable to
slightly dampen the cloth. Do not spray any kind

of cleaning agent on or in close proximity
to the electrostatic element. Avoid the use of
ammonia based products or silicone oil on
the wood parts.

What is the advantage of ESL?

Since the diaphragm is uniformly driven over its entire
surface—unlike a tweeter that is only driven at its
edges— it is the only technology that can be made
large enough to play bass, yet is still light enough for
high frequencies. This unique property allows for the
elimination of high frequency crossover points and their
associated distortions.

Could you suggest a list of suitable elec­tronics and cables that would be ideal for
MartinLogan speakers?

The area of electronics and cable choice is probably
the most common type of question that we receive. It
is also the most subjective. We have repeatedly found
that brands that work well in one setup will drive some­one else nuts in another. We use many brands with
great success. Again, we have no favorites; we use
electronics and cables quite interchangeably. We
would suggest listening to a number of brands—and
above all else— trust your ears. Dealers are always the
best source for information when purchasing additional
audio equipment.

Why does my speaker make popping noises
and hums?

The Purity features a built in muting circuit that will
detect popping anomalies and minimize them.

When using the speaker level inputs a popping noise
may occur when the amplifier is turned on or off. This is
caused by grounding interaction between the speaker
and the amplifier. It is normal and to be expected.

When making or breaking connections from devices that
utilize the Line Level input a popping noise may occur.

This is caused by grounding and static discharge inter­action. It is normal and to be expected when using this
method of connection. If a cable is connected to the
speaker, but is left unterminated at the device end you
may also experience a low-level hum. To minimize these
intermittent noises we recommend using a device that is
permanently connected (such as a digital music player
docking station).

Is there likely to be any interaction between my
speakers and the television in my Audio/Video
system?

Actually, there is less interaction between a television
and an electrostatic speaker than between a television
and a conventional system. However, we do recommend
that you keep your speakers at least one foot away
from the television because of the dynamic woofer they
employ.

Will my electric bill go ‘sky high’ by leaving my
speakers plugged in all the time?

No. A pair of MartinLogan’s will draw about 8 watts
maximum (idle). There is circuitry to turn off the static
charge when not in use; however, actual consumption
will remain close to the same. The primary purpose of
the sensing circuitry is to prevent dust collection on the
electrostatic element.

If the diaphragm is punctured with a pencil or
similar item, how extensive would the damage
to the speaker be?

Our research department has literally punctured hundreds
of holes in a diaphragm, neither affecting the quality of
the sound nor causing the diaphragm to rip. However,
you will be able to see the actual puncture and it can
be a physical nuisance. If this is the case, replacing the
electrostatic transducer will be the only solution.

Will exposure to sunlight affect the life or per­formance of my speakers?

We recommend that you not place any loudspeaker
in direct sunlight. The ultraviolet (UV) rays from the sun
can cause deterioration of grill cloth, speaker cones,
etc. Small exposures to UV will not cause a problem.
In general, the filtering of UV rays through glass will
greatly reduce the negative effects on the electrostatic
membrane itself.

Frequently Asked Questions 19

Will excessive smoke or dust cause any prob­lems with my electrostatic speakers?

Exposure to excessive contaminants such as smoke
or dust may potentially affect the performance of the
electrostatic membrane, and may cause discoloration
of the diaphragm membrane. When not in use for
extended periods, you should unplug the speakers and
cover them with the plastic bags in which the speakers
were originally packed. It is a good idea to vacuum
the electrostatic portion of each speaker three or four
times a year. See the vacuuming FAQ.

A problem has recently developed with my
MartinLogan speakers. The right speaker
seems to be hissing even when the amplifier
and such are not connected. I was wonder­ing if this sounds like any problem you have
encountered previously and have a simple
solution for or might it be something which will
need to be looked into more carefully.

Your speakers are dusty. See the vacuuming FAQ. The
electrostatic charge on the element has attracted airborne
dust or pollen. Since 1993, all of our speakers have
been built with a charging circuit board that only charg­es the electrostatic element when music plays. At other
times they are not charged and cannot collect dust. You
can get the same benefit by simply unplugging them
whenever they are not in use. A power strip is an easy
way to do that.

Could my children, pets, or myself be shocked
by the high-voltage present in the electrostatic
panel?

No. High voltage with low current is not dangerous.
As a matter of fact, the voltage in our speakers is 10
times less than the static electricity that builds up on the
surface of your television screen.

How do MartinLogan speakers hold up over a
long term in the humidity of tropical climates?

We should tell you that MartinLogan indeed has a very
substantial number of customers in tropical regions of
the world. Our speakers have been serving them nicely
for many years. This concern may have come from our
earlier design of speakers, which were charged con­tinuously. Since 1993, all of our speakers have been
designed so that they only charge the panel while
music is being played. This improvement has made a
tremendous difference in the consistent performance of
our product. There may be a little more maintenance
involved in humid regions when not in an air condi­tioned environment. Simply enough, the concern is to
keep the electrostatic panels dust free. Humidity will
combine with any dust on the panel to make it slightly
conductive. This will result in a slight pathway for the
charge to leave the membrane of the speaker. The solu­tion is simple. They only require occasional vacuuming
with a strong vacuum hose.

How do I vacuum my MartinLogan speakers?

Vacuuming will be most effective if the speakers have
been unplugged for six hours to twelve hours (or over­night). You need not worry about the vacuum pressure
damaging the "delicate" membrane. It is extraordi­narily durable. Dirt and dust may be vacuumed off. Use
an open hose with your finger tips at the opening act­ing as a soft bumper to prevent the hose from scratching
the coating of the panel. When vacuuming or blowing
off your panels do so to both sides, but focus the major­ity of your attention on the front of the panels.

Should I unplug my speakers during a thun­derstorm?

Yes, or before. It’s a good idea to disconnect all of
your audio/video components during stormy weather.

20 Frequently Asked Questions

TROUBLESHOOTING

No Output

• Check that all your system components are turned on.

• Check your speaker wires and connections.

• Check all interconnecting cables.

• Try hooking up a different set of speakers. The lack of
output could point to a problem with other equipment in
your system (amp, pre-amp, processor, etc.)

Weak or no Output from Electrostatic Panel, Loss
of Highs

• Check the power cord. Is it properly connected to the
speaker and to the wall?

• Is the power cord connected to a switched outlet?

• Dirt and dust may need to be vacuumed off. Please see
the FAQ regarding vacuuming.

• Check the binding posts. Are the dirty? If so clean them
with rubbing alcohol.

• Check the binding posts. Are the loose? Make sure
they are firmly hand-tightened.

• Has a foreign substance (such as a household cleaning
chemical or soap) been applied to the panel? If so the
speaker will require servicing.

Popping and Ticking Sounds, Funny Noises

• These occasional noises are harmless and will not hurt
your audio system or your speakers. All electrostatic
speakers are guilty of making odd noises at one time or
another. It is the result of airborne contaminates (most
notably dust). Vacuuming is recommended.

• These noises may be caused by dirt and dust particles
collecting on the speaker, by high humidity.

• Dirt and dust may need to be vacuumed off. Please see
the FAQ regarding vacuuming.

Exaggerated Highs, Brightness

• Check the toe-in of the speakers. Read the Placement
section of this manual for more information.

Muddy Bass

• Check placement. Try moving the speakers closer to the
front and sidewalls.

• Possibly means low electrostatic panel output. See
'Weak Output from Electrostatic Panel, Loss of Highs’.

Lack of Bass, No Bass

• Check your speaker wires. Is the polarity correct?

• Check the binding posts. Are the dirty? If so clean them
with rubbing alcohol.

• Check the binding posts. Are the loose? Make sure
they are firmly hand-tightened.

Poor Imaging

• Check placement. Are both speakers the same distance
from the walls? Do they have the same amount of toe­in? Try moving the speakers away from the back and
sidewalls.

• Check the polarity of the speaker wires. Are they con­nected properly?

• Try switching the left speaker with the right.

• Are your speakers set up in an L-shaped room? If so,
you may experience off-center imaging. Talk to your
dealer about acoustical room treatment options.

Troubleshooting 21

GENERAL INFORMATION

Specifications* Warranty and Registration

System Frequency Response:

41–23,000 Hz ± 3db

Dispersion

Horizontal: 30 Degrees
Vertical: 28” (71 cm) Line Source

Sensitivity

93 dB/2.83 volts/meter (binding posts)
95 dB/2.83 volts/meter (line level input)

Impedance

4,000 Ohms (binding posts)
14,000 Ohms (line level input)

Crossover Frequency

450 Hz

Components

Custom-wound audio transformer, air core coils, high-effi­ciency, high-resolution amplifier

Bass Level Control

+3dB, flat, –3dB

Your Purity speakers are provided with an automatic
Limited 90 Day Warranty coverage. You have the

option, at no additional charge, to receive a Limited
5 Year Warranty coverage. To obtain the Limited
5 Year Warranty coverage you need to complete and
return the Certificate of Registration, included with your
speakers, and provide a copy of your dealer receipt, to
MartinLogan within 30 days of purchase. For your conve­nience MartinLogan also offers online warranty registration at
www.martinlogan.com.

MartinLogan may not honor warranty service claims unless
we have a completed Warranty Registration card on
file! If you did not receive a Certificate of Registration with

your new Purity speakers you cannot be sure of having
received new units. If this is the case, please contact your
authorized MartinLogan dealer.

Serial Number

Purity’s serial number is located near the binding posts. Each
individual unit has a unique serial number.

Service

Woofer Type

Two 6.5” (16.5 cm) high excursion, aluminum cone with
extended throw driver assembly, non-resonance asymmetri­cal chamber format, bass reflex

Internal Amplifier

200 watts

Recommended Amplifier Power

50–200 watts

AC Mains Power Draw

Maximum Current Draw: 3 amps
Maximum Power: 250 watts
Standby Power: 10 watts

Weight

51 lbs. each (23.2 kg)

Size

52.3” h x 9.7” w x 14.7” d
(132.9 h x 24.5 w x 37.3 d cm)

Should you be using your MartinLogan product in a country
other than the one in which it was originally purchased,
we ask that you note the following:

1 The appointed MartinLogan 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 MartinLogan 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 MartinLogan 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 MartinLogan product.

3 If, after owning your speakers for six months, you

relocate to a country other than the one in which
you purchased your speakers, your warranty may be
transferable. Contact MartinLogan for details.

*Specifications are subject to change without notice.

22 General Information

DIMENSIONAL DRAWINGS

Dimensional Drawings 23

GLOSSARY OF AUDIO TERMS

AC. Abbreviation for alternating current.

Active crossover. Uses active devices (transistors, IC’s,

tubes) and some form of power supply to operate.

Amplitude. The extreme range of a signal. Usually mea-

sured from the average to the extreme.

Arc. The visible sparks generated by an electrical discharge.

Bass. The lowest frequencies of sound.

Bi-Amplification. Uses an electronic crossover, or line-

level passive crossover, and separate power amplifiers for
the high and low frequency loudspeaker drivers.

Capacitance. That property of a capacitor which deter-

mines how much charge can be stored in it for a given
potential difference between its terminals, measured in
farads, by the ratio of the charge stored to the potential
difference.

Capacitor. A device consisting of two or more conducting

plates separated from one another by an insulating mate­rial and used for storing an electrical charge. Sometimes
called a condenser.

Clipping. Distortion of a signal by its being chopped

off. An overload problem caused by pushing an amplifier
beyond its capabilities. The flat-topped signal has high levels
of harmonic distortion which creates heat in a loudspeaker
and is the major cause of loudspeaker component failure.

CLS. The abbreviation for curvilinear linesource.

Crossover. An electrical circuit that divides a full band-

width signal into the desired frequency bands for the
loudspeaker components.

dB (decibel). A numerical expression of the relative loud-

ness of a sound. The difference in decibels between two
sounds is ten times the Base 10 logarithm of the ratio of
their power levels.

DC. Abbreviation for direct current.

Diffraction. The breaking up of a sound wave caused by

some type of mechanical interference such as a cabinet
edge, grill frame or other similar object.

Diaphragm. A thin flexible membrane or cone that

vibrates in response to electrical signals to produce sound
waves.

Distortion. Usually referred to in terms of total harmonic

distortion (THD) which is the percentage of unwanted har­monics of the drive signal present with the wanted signal.
Generally used to mean any unwanted change introduced
by the device under question.

Driver. See transducer.

Dynamic Range. The range between the quietest and

the loudest sounds a device can handle (often quoted in
dB).

Efficiency. The acoustic power delivered for a given elec-

trical input. Often expressed as decibels/watt/meter
(dB/w/m).

ESL. The abbreviation for electrostatic loudspeaker.

Headroom. The difference, in decibels, between the

peak and RMS levels in program material.

Hybrid. A product created by the marriage of two dif-

ferent technologies. Meant here as the combination of a
dynamic woofer with an electrostatic transducer.

Hz (Hertz). Unit of frequency equivalent to the number of

cycles per second.

Imaging. To make a representation or imitation of the original

sonic event.

Impedance. The total opposition offered by an electric

circuit to the flow of an alternating current of a single fre­quency. It is a combination of resistance and reactance and
is measured in ohms. Remember that a speaker’s imped­ance changes with frequency, it is not a constant value.

24 Glossary of Audio Terms

Inductance. The property of an electrical circuit by which

a varying current in it produces a varying magnetic field
that introduces voltages in the same circuit or in a nearby
circuit. It is measured in henrys.

Inductor. A device designed primarily to introduce induc-

tance into an electrical circuit. Sometimes called a choke
or coil.

Linearity. The extent to which any signal handling pro-

cess is accomplished without amplitude distortion.

Midrange. The middle frequencies where the ear is the

most sensitive.

Passive crossover. Uses no active components (transis-

tors, IC’s, tubes) and needs no power supply (AC, DC,
battery) to operate. The crossover in a typical loudspeak­er is of the passive variety. Passive crossovers consist of
capacitors, inductors and resistors.

Phase. The amount by which one sine wave leads or lags

a second wave of the same frequency. The difference is
described by the term phase angle. Sine waves in phase
reinforce each other; those out of phase cancel.

Resistor. A device used in a circuit to provide resistance.

Resonance. The effect produced when the natural vibra-

tion frequency of a body is greatly amplified by reinforcing
vibrations at the same or nearly the same frequency from
another body.

Sensitivity. The volume of sound delivered for a given

electrical input.

Stator. The fixed part forming the reference for the moving

diaphragm in a planar speaker.

THD. The abbreviation for total harmonic distortion. (See

Distortion)

TIM. The abbreviation for transient intermodulation distortion.

Transducer. Any of various devices that transmit energy

from one system to another, sometimes one that converts
the energy in form. Loudspeaker transducers convert electri­cal energy into mechanical motion.

Transient. Applies to that which lasts or stays but a short

time. A change from one steady-state condition to another.

Pink noise. A random noise used in measurements, as it

has the same amount of energy in each octave.

Polarity. The condition of being positive or negative with

respect to some reference point or object.

RMS. Abbreviation for root mean square. The effective value

of a given waveform is its RMS value. Acoustic power is
proportional to the square of the RMS sound pressure.

Resistance. That property of a conductor by which it oppos-

es the flow of electric current, resulting in the generation of
heat in the conducting material, usually expressed in ohms.

Tweeter. A small drive unit designed to reproduce only

high frequencies.

Wavelength. The distance measured in the direction of

progression of a wave, from any given point character­ized by the same phase.

White noise. A random noise used in measurements, as

it has the same amount of energy at each frequency.

Woofer. A drive unit operating in the bass frequencies

only. Drive units in two-way systems are not true woofers
but are more accurately described as being mid/bass
drivers.

Glossary of Audio Terms 25

NOTES

26 Notes

Notes 27

WARNING! Do not use your Purity 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
Purity 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].

®

Lawrence, Kansas, USA tel [phone] fax [phone] www.martinlogan.com

©2007 MartinLogan. All rights reserved. Rev. #050907