MartinLogan Speaker Monolith III User Manual

User's Manual  
The Monolith III Speaker System  
 
Introduction  
Congratulations, you have invested in  
one of the world’s premier loudspeaker  
systems!  
many areas of loudspeaker design.  
Bass response has better extension,  
superior impact and improved defini-  
tion, high frequency response also has  
better extension and is much more  
natural in character. Much effort was  
spent on minimizing all diffractive or  
reflective surfaces. This has improved  
overall transparency and image quality.  
hardwood powderboard for structural  
integrity and is finished with a durable  
and attractive leatherette.  
The Martin-Logan MONOLITH III repre-  
sents the culmination of an intensive,  
dedicated group research program  
directed toward establishing a world  
class reference monitor utilizing  
leading-edge technology, without  
compromising durability, reliability,  
craftsmanship, or aesthetic design.  
Through rigorous testing, the curvilinear  
electrostatic panel manufactured and  
used by Martin-Logan 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 nylon/  
Delrin based polymer that is applied via  
In addition, a great amount of energy  
was spent on the interface between the  
electrostatic element and the woofer,  
The original Monolith made its official  
debut in June of 1982 at the Interna-  
tional Consumer Electronics Show  
with astonishing results. The fruit of this a proprietary electrostatic deposition  
labor has brought us the passive IIIp  
INTERFACE and the superior electronic  
process. This panel assembly houses  
a membrane 0.0005 of an inch thick!  
Ruggedly constructed and insulated, as  
much as 200 watts of continuous  
where it was selected for the prestigous IIIx CROSSOVER. With either of these two  
Design and Engineering Exhibition as  
one of the most innovative consumer  
electronics products of that year. Since  
then, the Monolith has become the  
devices, the transition from the electro-  
static element to the woofer becomes  
invisible and an unbelieveable continu-  
ity of sound prevails. With the IIIx  
power has driven the MONOLITH III's  
energized diaphragm into massive  
excursions with no deleterious effects.  
speaker of choice by the most demand- CROSSOVER another veil is lifted and  
ing musicians, electronics manufactur-  
ers, and recording studios, as well as  
the most discerning critical listeners.  
you are brought even closer to the  
musical truth. Dynamic information  
suddenly becomes frightening. Power  
handling and system efficiency are  
enhanced as well.  
We again thank you for purchasing the  
MONOLITH III. By following the Installa-  
tion in Brief instructions you may  
connect them to your system, sit back,  
relax, and enjoy this most exacting  
transducer. It has been designed and  
As a result of our continuous research  
and development program here at  
Martin-Logan, we decided that it was  
time to incorporate some of our latest  
technologies into the already outstand-  
ing Monolith. So, in January of 1990 we  
introduced the MONOLITH III to the  
marketplace.  
Like the original Monoliths, all materials constructed to give you years of trouble-  
in your new MONOLITH III speakers are  
of the highest quality to provide years of  
enduring enjoyment and deepening  
respect. All trim pieces are constructed  
from selected hardwoods. They are  
then grain and color matched and finally  
hand finished. The cabinetry is con-  
structed from a special high-density  
free listening enjoyment.  
Happy Listening!  
With the MONOLITH III, we have ad-  
vanced the current state of the art in  
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Monolith III User's Manual  
 
Installation in Brief  
We know you are eager to hear  
Step 1: Placement  
your new MONOLITH III loudspeak-  
ers, 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  
Place each Monolith at least two feet from any wall and slightly angle them  
toward your listening area. This is a good place to start. Please refer to the  
Room Acoustics and Placement sections of this manual for more details.  
manual. It will give you perspective  
on how to obtain the best possible  
performance from this most  
Step 2: Power Connection (AC)  
exacting transducer.  
Martin-Logan Monoliths require AC power to energize their electrostatic cells.  
Using the AC power cords provided, plug them in, making sure that you have  
made a firm connection, first to the AC power receptacle on the rear panel of  
the speaker and then to the wall outlet. Extension cords may be used, if  
necessary, since the AC power requirement of the Monolith is extremely small.  
If you should experience any  
difficulties in the set-up or opera-  
tion of your MONOLITH III speakers  
please refer to the Room Acoustics,  
Placement or Connection section  
of this manual.  
Step 3: Signal Connection  
Should you encounter a persistent  
problem that cannot be resolved,  
please contact your Authorized  
Martin-Logan dealer. He will  
provide you with the appropriate  
technical analysis to alleviate the  
situation.  
WARNING !  
Turn your amplifier off before making or breaking any signal connections!  
The chassis is earth grounded and can present a short circuit to your  
amplifier if contact is made!  
Use the best speaker cables you can! 16 gauge zip-cord is the minimum you  
should use, and higher quality cables, available from your specialty dealer, are  
recommended and will give you superior performance! Spade or banana  
connectors are suggested for optimum contact and ease of installation.  
Be consistent when connecting speaker leads to the terminals on the back of  
the MONOLITH III: 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, reverse the (+) and (-) leads on one side to bring the  
system into proper polarity. Attach your speaker cables to the Amplifier Signal  
input section of the IIIp INTERFACE if you have the MONOLITH IIIp or directly to the  
appropriate Signal Input section on the back of the MONOLITH III if you are using  
the MONOLITH IIIx CROSSOVER. Please refer to the appropriate Connection  
section of this manual for further details and instructions.  
Step 4: Listen and Enjoy  
Now, you may turn on your system and enjoy!  
Page4  
Monolith III User's Manual  
 
Monolith III Specifications  
The MONOLITH III hybrid speaker  
system consists of a broad-range  
single element electrostatic transducer  
integrated with a quick-response  
woofer. This approach takes maximum  
advantage of the positive aspects that  
both technologies have to offer.  
electrostatic transducer element itself,  
an elegantly simple solution.  
Dispersion is a controlled 30 degrees.  
This was achieved by curving the  
MONOLITH III SPEAKER  
System Frequency Response  
28-24,000 Hz +/-2dB  
Impedance  
High-pass:  
Weight  
120 lbs/speaker; 54.4 kg/speaker  
Nominal: 4 ohms, below 10kHz  
Minimum: 1 ohm @ 20kHz  
Low-pass:  
Nominal: 4 ohms  
Minimum: 4 ohms  
Electrostatic Frequency Response  
95-24,000 Hz +/- 2dB  
Size (HWD)  
73.75" x 26.75" x 11.75"  
187.3cm x 67.9cm x 29.8cm  
Woofer Frequency Response  
28-2,000 Hz +/- 2dB  
Components  
Power Handling  
250 watts per channel  
Glass-epoxy boards,  
Dispersion  
Horizontal: 30 Degrees  
Vertical: 4' Line Source  
custom-wound audio transformers,  
30-amp gold plated binding posts,  
regulated HV power supply  
Recommended Amplifier Power  
80 - 250 watts per channel  
Sensitivity  
89dB/2.83 Volts/meter  
IIIp INTERFACE  
IIIx CROSSOVER  
Circuit Topology  
Crossover Frequency  
125 Hz @ 12dB/octave  
Crossover Frequency  
Audio circuits are fully complimen-  
tary, class-A current-biased J-FET  
buffers that isolate passive filter  
networks.  
125 Hz:  
@12dB/octave low-pass  
@18dB/octave high-pass  
Impedance  
Nominal: 4 ohms, below 10kHz  
Minimum: 1 ohms @ 20kHz  
Input Impedance  
47,000 ohms  
Power supply employs a toroidal  
transformer , discrete voltage and  
self-tracking current regulation.  
40-volt peak to peak swing allows  
for 30dB of dynamic headroom.  
Components  
Output Impedance  
100 ohms  
Glass-epoxy boards,  
polypropylene capacitors,  
100% OFC coils,  
Distortion  
wirewound resistors,  
30-amp gold plated binding posts,  
non-ferrous enclosure  
0.003% THD @ 1kHz @ 1Vrms  
Components  
Glass-epoxy boards, metal film  
resistors, polypropylene capacitors,  
hand picked J-FETs, TIFFANY  
input/output connectors  
Signal to Noise  
Greater than -95dB  
Page5  
Monolith III User's Manual  
 
History  
In the late 1800’s, any loudspeaker was and loudspeaker to take advantage of  
considered exotic. Today, most of us the new recording medium. Bell Labs  
take the wonders of sound reproduction assigned the project to two young  
acoustic gramophone was destined to  
become obsolete.  
for granted.  
engineers, C.W. Rice and E.W. Kellogg. Due to Rice and Kelloggs enthusiasm,  
they devoted a considerable amount of  
It was 1880 before Thomas Edison had Rice and Kellogg had a well equipped  
time researching the electrostatic  
design. However, they soon encoun-  
tered the same difficulties that even  
present designers face; planar speak-  
ers require a very large surface area to  
reproduce the lower frequencies of the  
audio spectrum. Because the manage-  
ment at Bell Labs considered large  
speakers unacceptable, Rice and  
Kelloggs 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.  
invented the first phonograph. This was  
a horn-loaded diaphragm that was  
laboratory at their disposal. This lab  
possessed a vacuum tube amplifier  
excited by a playback stylus. In 1898, Sir with an unheard of 200 watts, a large  
Oliver Lodge invented a cone loud-  
speaker, which he referred to as a  
“bellowing telephone”, that was very  
similar to the conventional cone  
selection of the new electrically cut  
phonograph records and a variety of  
loudspeaker prototypes that Bell Labs  
had been collecting over the past  
loudspeaker drivers that we know today. decade. Among these were Lodge’s  
However, Lodge had no intention for his cone, a speaker that used compressed  
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 loud-  
speaker, as we know it today, should  
have ensued then, but it did not.  
Amazingly, it was almost twenty years  
before this would occur.  
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 “conven-  
tional”,orexotic”.  
During the Great Depression of the  
1930's, consumer audio almost died.  
The new electrically amplified loud-  
speaker never gained acceptance, as  
most people continued to use their old  
Victrola-style acoustic gramophones.  
Prior to the end of World War II, con-  
sumer audio saw little, if any, progress.  
However, during the late 1940's, audio  
experienced a great rebirth. Suddenly  
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 there was tremendous interest in audio  
gold leaf to conduct the audio signal.  
In 1921, the electrically cut phonograph  
record became a reality. This method of  
recording was far superior to the  
mechanically cut record and pos-  
sessed 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 loud-  
speakers were needed to cope with  
this amazing new recording medium.  
products and with that, a great demand  
for improved audio components. No  
sooner had the cone become estab-  
lished than it was challenged by  
products developed during this new  
rebirth.  
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  
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  
By 1923, Bell Telephone Laboratories  
made the decision to develop a  
complete musical playback system  
consisting of an electronic phonograph  
Page6  
Monolith III User's Manual  
 
extremely accurate speaker, but  
Janszen found that the cone speakers  
of the period were too nonlinear in  
surfaces by electrostatic forces. Due to  
these characteristics, electrostats have  
the inherent ability to produce a wide  
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.  
phase and amplitude response to meet bandwidth, flat frequency response with  
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.  
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 perform-  
ance 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 presented a  
difficult load that some amplifiers did  
not like, its dispersion was very  
Electrostatic speakers have pro-  
gressed and prospered because they  
actually do what Peter Walker claimed  
they would. The limitations and prob-  
lems experienced in the past were not  
inherent to the electrostatic concept.  
They were related to the applications of  
these concepts.  
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 electro-  
static tweeter element ready for  
commercial production. This new  
tweeter soon created a sensation  
among American audio hobbyists.  
Since Janszen's tweeter element was  
directional, and its power handling was  
limited to around 70 watts. As a result,  
many people continued to use box  
speakers with cones.  
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.  
Todays electrostats use advanced  
insulation techniques or provide  
In the early 1960's Arthur Janszen  
limited to high frequency reproduction, it joined forces with the KLH loudspeaker  
often found itself used in conjunction  
with woofers, most notably, woofers  
from Acoustic Research. These  
systems were highly regarded by all  
audio enthusiasts.  
company and together they introduced  
the KLH 9. Due to the large size of the  
KLH 9, it did not have as many limita-  
tions as the Quad. The KLH 9 could  
play markedly louder and lower in  
frequency than the Quad ESL. Thus a  
rivalry was born.  
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.  
As good as these systems were, they  
would soon be surpassed by another  
electrostatic speaker.  
Janszen continued to develop electro-  
static designs. He was instrumental in  
the design of the Koss Model One, the  
Acoustech, and the Dennesen speak-  
ers. Roger West, the chief designer of  
the JansZen Corporation became the  
These developments allow the con-  
sumer 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.  
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 president of Sound Lab. When JansZen  
electrostatic loudspeaker. He explained  
that electrostatics permit the use of  
diaphragms that are low in mass, large  
in area, and uniformly driven over their  
Corporation was sold, the RTR  
loudspeaker company bought half of  
the production tooling. This tooling was  
used to make the electrostatic panels  
Page7  
Monolith III User's Manual  
 
Connection  
AC Power Connection  
Signal Connection  
Electrostatic speakers use an internal power supply to  
energize their electrostatic elements with high-voltage DC  
(low current). As such, they must be connected to an AC  
wall outlet. For this reason we have provided your speakers  
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. Extension cords may be used, if  
necessary, since the AC power requirement of the speaker  
is extremely small (less than 2.5 watts).  
Use the best speaker cables you can! The length and type  
of speaker cable used in your system will have an audible  
effect. Under no circumstance should a wire of gauge  
higher (thinner) than #16 be used. In general, the longer  
the length used, the greater the necessity of a lower gauge,  
and the lower the gauge, the better the sound, with dimin-  
ishing returns setting in around #8 to #12.  
A variety of speaker cables are now available whose  
manufacturers claim better performance than with standard  
heavy gauge wire. We have verified this in some cases,  
and the improvements available are often more noticeable  
than the differences between wires of different gauge.  
We do not recommend the use of "super cords", as many  
of these designs eliminate the ground prong of the male  
plug and therefore do not follow IEC convention standards.  
If proper plugs are fitted, then the choice is up to you.  
We would also recommend, if possible, that short runs of  
speaker cable connect the power amplifier(s) and speak-  
ers and that high quality long interconnect cables be used  
to connect the preamplifier and power amplifier. This  
results in the power amplifiers being close to the speakers,  
which may be practically or cosmetically difficult, but if the  
length of the speaker cables can be reduced to a few  
meters, sonic advantages may be obtained. The effects of  
cables may be masked if the equipment is not of the  
highest quality.  
Your Martin-Logan speakers have been designed to  
remain on continuously and should remain connected to a  
continuous AC power source. As mentioned earlier, power  
consumption of the MONOLITH III is very small and the life  
expectancy of its components will not be reduced by  
continuous operation.  
The power cord should not be installed, removed,  
or left detached from the speaker while the other  
end is connected to an AC wall outlet.  
Connections are done at the SIGNAL INPUT section on the  
rear electronics panel of the MONOLITH III. Use spade or  
banana connectors for optimum contact and ease of  
installation. Make certain that all your connections are  
clean, tight and positive.  
Your Martin-Logan speakers are wired for the power  
service supplied in the country of original consumer sale  
unless manufactured on special order. The AC power  
rating applicable to a particular unit is specified both on the  
packing carton and on the serial number plate attached to  
the speaker.  
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 probably need to  
reverse the (+) and (-) leads on one speaker to bring the  
system into proper polarity.  
If you remove your Martin-Logan speakers from the country  
of original sale, be certain that AC power supplied in any  
subsequent location is suitable before connecting and  
operating the speakers. Substantially impaired perform-  
ance or severe damage may occur to a Martin-Logan  
speaker if operation is attempted from an incorrect AC  
power source.  
The MONOLITH IIIp INTERFACE provides you with three  
different methods for connecting the MONOLITH III to your  
audio system, while the superior MONOLITH IIIx CROSSOVER  
uses active bi-amplification.  
If your home is not equipped with three-prong wall outlets,  
you may use “cheater” plugs to connect the speakers to AC  
power. However, please make certain that you connect the  
grounding wire or tab of the plug to a ground. These may  
be obtained at your dealer or any hardware department.  
Page8  
Monolith III User's Manual  
 
IIIp Connection  
ONE: Standard Connection for MONOLITH IIIp.  
Please take note of the jumpers installed  
across the binding posts of the IIIp INTER-  
FACE. These jumpers attach the high-pass  
and the low-pass sections of the interface  
together. Leaving these in place, connect  
the (+) wire from your amplifier to either of  
the red AMPLIFIER SIGNAL binding posts of  
the Interface and the (-) wire to either of the  
black posts. Next, connect the IIIp INTERFACE  
to the MONOLITH III with the provided cables.  
See Figure 1.  
Figure 1: Standard connection for the MONOLITH IIIp.  
TWO: Bi-wire Connection for the MONOLITH IIIp.  
This method of connection replaces the  
jumpers installed across the binding posts  
of the IIIp INTERFACE with individual runs of  
speaker wire from your amplifier. This  
doubles the signal carrying conductors from  
the amplifier to the speaker thus, direct-  
coupling each portion of the crossover to the  
amplifier.  
To bi-wire you must first remove the  
jumpers from the IIIp INTERFACE. Connect  
one set of wires to the HI+ and HI- binding  
posts of the IIIp INTERFACE. Then connect a  
second set of wires to the LO+ and LO-  
binding posts. Next, connect both sets of  
wires to the appropriate terminals on your  
amplifier. See Figure 2. Please take care to  
connect both (+) wires to the (+) amplifier  
terminals and both (-) wires to the (-)  
Figure 2: Bi-wire connection for the MONOLITH IIIp.  
amplifier terminals. This is known as a  
parallel connection.  
Page9  
Monolith III User's Manual  
 
IIIp Connection  
THREE: Passive Bi-amplification.  
The MONOLITH III may be passively bi-  
amplified using the IIIp INTERFACE.  
outputs. If your pre-amplifier is not so  
equipped then you must purchase or  
construct a "Y" adapter.  
However, we recommend that you use  
two identical amplifiers (i.e. same brand  
and model). If the ampliers of choice do  
not have the same gain characteristics,  
then a sonic imbalance will occur  
between the high-pass and low-pass  
sections of the speaker and integration  
between the two will suffer greatly. By  
using identical amplification on the  
high-pass and the low-pass you will  
You cannot use an external electronic  
crossover with the MONOLITH III (other  
than the IIIx CROSSOVER which re-  
places the IIIp INTERFACE)!  
Horizontal bi-amping allows you to  
use two different types, models or  
brands of amplifiers (i.e. tubes on top,  
transistor on the bottom), assuming  
that they have identical gain or that one  
stereo pair has adjustable gain.  
Passive bi-amplification takes the bi-  
wiring concept one step further. Now  
you will have a dedicated channel of  
amplification directly connected to the  
high and low-pass sections of the  
crossover.  
There are two different methods to  
passively bi-amplify. The first, and  
most common, is referred to as  
Horizontal Bi-amping. The second  
method that is gaining in popularity is  
referred to as Vertical Bi-amping. With  
either method you may use two stereo  
amplifiers, or four mono amplifiers, or  
two mono amplifiers and one stereo  
amplifier. Get the idea here? With  
either form of passive bi-amplification,  
your pre-amplifier must have dual  
Figure 3a: Horizontal passive bi-amplification connection for the MONOLITH IIIp.  
Page10  
Monolith III User's Manual  
 
eliminate the negative effects of time  
delay (also referred to as group delay)  
that occurs when a signal passes  
through two dissimilar amplifiers. The  
very nature of vertical bi-amping  
low-pass section. To  
                                                                                                                              
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z
                                                                                                                                    
                                                                                                                                      
o
                                                                                                                                      
                                                                                                                                        
n
                                                                                                                                        
                                                                                                                                          
t
                                                                                                                                          
                                                                                                                                           
a
                                                                                                                                           
                                                                                                                                             
l
                                                                                                                                             
                                                                                                                                              
l
                                                                                                                                              
                                                                                                                                              
y
                                                                                                                                               
                                                                                                                                                  
b
                                                                                                                                                  
                                                                                                                                                    
i
                                                                                                                                                    
                                                                                                                                                     
-
                                                                                                                                                     
outputs to the appropriate left and right  
inputs of both amplifiers. See Figure  
3a.  
amp your Monoliths you must remove  
the jumpers from the AMPLIFIER SIGNAL  
binding postsof the IIIp INTERFACE.  
Connect the low frequency amplifier to  
the LO+ and LO- AMPLIFIER SIGNAL  
binding posts of each IIIp INTERFACE.  
With vertical bi-amping, each of the  
stereo amplifiers is dedicated to one  
speaker. For instance, the left channel  
dictates that both amplifiers be identical.  
With horizontal bi-amping, one  
Connect the high frequency amplifier to of each amplifier drives the low -pass  
amplifier drives the high-pass section  
while the second amplifier drives the  
the HI+ and HI- binding posts. Next  
connect the left and right preamplifier  
section while the right channel drives  
the high-pass section. To vertically bi-  
amp your Monoliths, you must remove  
the jumpers from the AMPLIFIER SIGNAL  
binding posts of each IIIp INTERFACE.  
Start by connecting the left amplifier  
channel of amplifier #1 to the LO+ and  
LO- binding posts and the right  
amplifier channel of amplifier #1 to the  
HI+ and HI- binding posts of the IIIp  
INTERFACE. Then repeat the same  
procedure for the other speaker with  
amplifier #2. Connect the left preampli-  
fier outputs to both inputs of the left  
channel amplifier (#1) and the right  
preamplifier outputs to both inputs of  
the right channel amplifier (#2). See  
Figure 3b.  
Figure 3b: Vertical passive bi-amplification connection for the MONOLITH IIIp.  
Page11  
Monolith III User's Manual  
 
IIIx Connection  
Introduction  
the crossover of the speaker they are  
divided into high and low frequency  
signals. The lower frequency signals  
are then directed to the woofers, while  
the high frequencies are routed to the  
electrostatic panels. This is known as a  
high-level passive crossover. This  
means that the frequency division of the  
signal is done after the power amplifier  
at high power (several volts) by means  
of passive components (capacitors,  
resistors, inductors and transformers).  
frequencies of a narrow bandwidth,  
thus it cannot combine high and low  
frequency signals and produce sum  
and difference by-products (intermodu-  
lation distortion or IM). For example, to  
reproduce deep bass such as an organ  
tone or kick drum, very high power  
(current) is needed. Since the low  
frequencies have their own dedicated  
amplifier, this demand for low frequency  
power will not affect the ability of the  
high frequency amplifier to perform its  
function normally, whereas if all  
The MONOLITH IIIx system utilizes the  
electronic IIIx CROSSOVER which  
incorporates technology developed for  
our STATEMENT SYSTEM CROSSOVER.  
Use of the MONOLITH IIIx CROSSOVER  
will result in substantial improvements  
in all aspects of your system's perform-  
ance. Bass will be more extended with  
more impact and control. Special bass  
contour controls allow you to tailor the  
bass response to suit your particular  
room environment or listening tastes.  
The crossover region between the  
woofer and electrostatic panel is  
optimized, thus making the system  
blend much more homogeneous.  
Highs are much more extended,  
detailed and effortless. The system  
becomes much more dynamic with  
less strain. To understand why this  
occurs, we need to look at the differ-  
ences between a single amplified  
system versus a properly interfaced bi-  
amplified system.  
When bi-amplifying with the MONOLITH  
IIIx CROSSOVER, the right and left full-  
bandwidth signals are divided into  
separate high and low frequency  
frequencies were reproduced by the  
same amplifier, its power supply might  
temporarily be depleted by the deep  
bass passage, causing dynamic  
signals after the pre-amplifier by means compression or clipping of the high  
of an active electronic crossover. These  
signals are then fed to dedicated high  
and low frequency amplifiers. This is  
referred to as a low-level active cross-  
over, because all frequency division of  
the signal is done at line level at very  
low power (millivolts) with active  
frequency material.  
Another added benefit of bandwidth  
limiting an amplifier, particularly the  
high frequency amplifier, is the slight  
increase in dynamic power output that  
occurs. The amplifier does not have to  
work as hard due to the reduction in the  
bandwidth amplification requirements.  
Therefore the amplifier can apply more  
power into the smaller frequency region.  
components (transistors).  
In a single amplified system, the left  
and right full-bandwidth signals pass  
from the preamplifier to a stereo power  
amplifier (or two mono amplifiers) and  
then to the loudspeaker's crossover,  
unchanged (we hope) except for  
This configuration has several advan-  
tages. With the frequency division of the  
signal done prior to amplification, each  
amplifier has only to contend with  
amplitude. Once these signals reach  
Warnings  
Packaging  
have occasion to return your unit to our  
factory for service, but in the event that  
servicing should prove necessary, or  
other occasion requiring shipment  
occurs, the original packaging will  
protect your unit from unnecessary  
damage or delay.  
To prevent fire or shock hazard, do not  
expose the MONOLITH IIIx CROSSOVER  
to rain or moisture.  
Please save all packaging and store in  
a dry place away from potential fire  
hazard. Your MONOLITH IIIx CROSSOVER  
is a precision electronic instrument and  
should be packaged properly in its  
original carton any time shipment is  
necessary. We hope that you will never  
Hazardous voltage potentials exist in  
this crossover. Do not operate with the  
cover removed. There are no user  
serviceable components inside. Refer  
servicing to your authorized Martin-  
Logan dealer only.  
Page12  
Monolith III User's Manual  
 
AC Power Connection  
convenient AC wall outlet. For absolute  
protection, do not defeat the power plug  
ground. This provides powerline  
grounding of the MONOLITH IIIx CROSS-  
OVER chassis and will protect you from  
electrical shock.  
Your MONOLITH IIIx CROSSOVER has no  
power switch as it has been designed  
to remain on continuously and should  
remain connected to a continuous AC  
power source.  
Plug in AC mains only after all  
signal connections have been  
made and you have verified that  
both amplifiers are switched off.  
Your crossover is wired for the power  
We do not recommend the replacement service supplied in the country of  
We have provided your MONOLITH IIIx  
CROSSOVER with the proper IEC  
standard 3-conductor power cords with  
3-prong grounding plug. This cord  
should be firmly inserted into the AC  
power receptacle located on the rear  
panel of the crossover, then to any  
or use of "deluxe" or "super" AC power  
cords. Many of these designs eliminate  
the ground prong of the male plug and  
therefore do not follow IEC convention  
standards. As such, they present the  
possibility of shock hazard.  
original consumer sale unless manu-  
factured on special order. The AC  
power rating applicable to a particular  
unit is specified both on the packing  
carton and on the serial number plate  
attached to the crossover.  
Signal Connection  
Insert your pre-amps' output cables into  
the crossovers' INPUT jacks, then  
connect your low-pass amplifiers' input  
cables to the crossovers' LOW OUT-  
PUT jacks, and your high-pass amplifi-  
ers' input cables to the  
HIGH OUTPUT jacks.  
Plug in AC mains only after all  
signal connections have been  
made and you have verified that  
both amplifiers are switched off.  
Next, connect the speaker leads from  
the high-pass amplifier to the HI  
SIGNAL INPUTS on the back of the  
MONOLITH III. Then connect the low-  
pass amplifier to the LO SIGNAL  
INPUTS. Please refer to the pictorial  
diagram, Figure 4 , at right.  
Figure 4: MONOLITH IIIx CROSSOVER connection.  
Page13  
Monolith III User's Manual  
 
IIIx Operation  
optimal setting is to locate the  
Crossover Settings  
Bass Contour Controls  
microphone of a spectrum analyzer in  
the room near your seating position,  
play pink noise through the system  
and begin to observe the relationship  
of the electrostatic transducer and the  
subwoofer at the crossover point  
which is 125 Hz. Your gain settings  
will be correct when the display is flat  
and consistent. You want the energy  
below 100 Hz to be roughly compa-  
rable to the energy above 100 Hz. If  
you now have reasonable tonal  
balance from 60 Hz onward to 200  
Hz, then you have the optimal  
Before you do any formal listening,  
you must set a pair of switches in the  
crossover. However, if you are using  
identical amplifiers (i.e. same make  
and model) for the high and low-pass  
sections of the Monolith, you may use  
the factory settings and skip this step.  
You will notice that there are two  
controls on the front of the MONOLITH  
IIIx CROSSOVER. The left control is  
labeled frequency and the right  
control is labeled boost/cut. (See  
Figure 6.) These are a very accurate  
and precise pair of controls that allow  
you to adjust your speakers output in  
the most problematic area of music  
reproduction; the bass region.  
On the back panel of the crossover  
there are two cut-outs that allow you  
to access two red dip switches. These  
switches adjust the low-pass gain so  
that you may balance the gain  
between the high-pass and low-pass  
amplifiers if they have different gain  
characteristics. We have even  
frequency balance at the crossover  
point.  
Your Room and Bass  
Today we are finding that all elements  
in the audio chain can and will affect  
your system's performance. Of these  
elements, your room is the worst  
offender. Once the precisely tailored  
musical signal is launched from your  
speaker system, your room then has  
Keep in mind that specifications and  
equipment can determine the best  
place to begin, but your ears are the  
most critical instruments available.  
Listen to music and adjust for your  
best personal balance.  
enclosed a red "dip stick" tool to assist  
you with this procedure.  
The following formula will help you  
calculate the relative gain of your  
amplifiers:  
its way with that  
musical signal;  
particularly with the  
larger wave-  
Amplifier gain is defined as:  
lengths of the  
bass region. Your  
room will enhance  
and cancel certain  
20 log  
(Rated Output @ 8 ohms) x 8  
Input Sensitivity  
ON  
GAIN  
ON  
GAIN  
None  
*1  
-6.0 dB  
-4.5 dB  
-3.0 dB  
-2.0 dB  
-1.5 dB  
-1.0 dB  
0 dB  
*5  
5&2  
5&3  
*6  
+1.5 dB  
At right, in Figure 5, is a list of switch  
settings to help you select the proper  
gain switch settings.  
+2.0 dB  
frequencies,  
*2  
+2.5 dB  
+3.0 dB  
+3.5 dB  
+4.0 dB  
+4.5 dB  
+5.0 dB  
+6.0 dB  
making a perfect  
speaker look less  
than perfect in the  
best of instances  
and like a jumbled  
mess in the worst  
of instances. The  
front panel  
2&1  
*3  
As you detent the switch towards the  
ON position, you are engaging that  
switch. Each switch detent away from  
position4eitherincreasesor  
decreases the output of the low-pass  
amplifier. In order to properly engage  
a switch, you need to have all other  
switches in the OFF position. If the  
high-pass and low- pass amplifiers are  
identical or have the same gain, the  
system is designed to operate with  
bothswitchessetto4(Position4”  
represents 0dB of gain).  
6&3  
6&5  
*7  
3&1  
*4  
4&1  
4&2  
+0.5 dB  
+1.0 dB  
7&6  
*8  
controls of the  
Figure 5: Low-pass attenuation switch settings.  
NOTE: Start with "*" settings first, then fine  
tune using the intermediate settings.  
crossover can be  
used much like an  
accurate bass/  
If equipped, the best way to obtain the  
Page14  
Monolith III User's Manual  
 
room equalizer, designed to neutral-  
ize the specific problem areas of your  
room, thus helping you optimize the  
performance of the MONOLITH III.  
sweeping from 100 Hz to 20 Hz and  
back again, and listening in different  
places in your room for what we call  
room nodes, or depressions, you can  
hear where the room either empha-  
sizes certain bass frequencies or  
cancels them. If you set the frequency  
control of the crossover to the same  
frequency as that of the "worst  
increases of music at each note, then  
you have an optimal sound with no  
need to adjust the crossover controls.  
However, if you note an absence or  
increase of energy at a specific area,  
adjust your frequency control to that  
frequency and boost or cut progres-  
sively depending on whether you want  
more bass or less bass. Here,  
Tuning Your Room  
One of the best ways to assess how  
your room is affecting your system's  
performance is by doing a 1/3 octave  
analysis of your room. These devices,  
called 1/3 octave analyzers, may be  
obtained or rented from your dealer.  
Some dealers can even provide you  
with this analysis. The information  
gained by this analysis will help you  
establish the proper control settings  
for your MONOLITH IIIx CROSSOVER,  
thus allowing you to bring your  
offender", and adjust the boost/cut  
control to its appropriate position  
(either up to cancel a void or down to  
cancel a peak), you should begin to  
establish a smooth progression from  
lows to highs. Your goal here is to  
have no lumps or recessions  
experimentation will be the factor.  
Inevitably, this is the final experiment.  
Even after using a sine-wave genera-  
tor or real-time analyzer you will want  
to listen and fine-tune your system  
with real music using your ears.  
throughout the low frequency sweep.  
Remember, what we often perceive  
as deep bass actually occurs at 40 to  
50 Hz. Energy below 30 Hz is virtually  
inaudible. You may sense it and feel it  
as pressurization and movement in  
your body, but you don’t really hear it.  
So, when you are experiencing bass  
energy, you will probably want to set  
your controls in the 30 to 50 Hz range  
and adjust them accordingly.  
If neither a real-time analyzer nor a  
sine-wave generator are available, put  
on your favorite musical cut with  
“moving bass” (bass information that  
moves up and down the scale). Listen  
carefully to this cut once or twice and  
note whether the progression of bass  
is smooth throughout the musical  
spectrum. If it is smooth and extended  
without any noticeable absences or  
system back to “flat” for optimal  
system performance.  
If a real-time analyzer is not available,  
a simple sine-wave generator and  
your ears may be used. By attaching  
the sine-wave generator to your  
system and slowly and consistently  
40 Hz  
0dB  
35 Hz  
30 Hz  
45 Hz  
50 Hz  
-2dB  
-4dB  
+2dB  
+4dB  
f r e q u e n c y  
b o o s t / c u t  
Figure 6: MONOLITH IIIx CROSSOVER Bass Contour controls.  
Page15  
Monolith III User's Manual  
 
IIIx Operation  
IIIx Technical Description  
Musical Tastes  
Theory of Operation  
In being a dedicated electronic  
crossover/equalizer, it is vital to tailor  
the system to the needs of the  
speaker. Planar speakers have two  
main areas of concern: 1) Rear wave  
cancellation, which causes a decrease  
in the speaker’s output below 500 Hz,  
and 2) Primary resonance, which is the  
frequency the speaker is tuned to.  
An added benefit of the contour  
controls on the IIIx CROSSOVER, is  
the ability to adjust your speaker's  
personality to your style of listening.  
The audio signal coming from the pre-  
amplifier of your audio system is  
typically representitive of a low imped-  
ance voltage source. There are a few  
preamplifiers, such as older tube  
designs, which may not conform to  
this, as they have a much higher output  
impedance. In addition many cables  
can change the preamplifiers output  
characteristics.  
It is well known that an “audiophile”  
listening priority is different from that of  
“rockorclassicEuropeanlistening  
orientation. By setting your frequency  
control to 30 Hz and the boost/cut  
control to 0dB, you will have what is  
known as the "Audiophile setting". This  
setting allows the deepest bass  
extension and most linear theoretic  
performance. Experimenting slightly  
with the boost/cut control will give you  
either a drier or deeper and more  
extended performance. However, if a  
“rock” orientation is your preference,  
set the frequency control between 40  
to 50 Hz with a slight boost, and you  
will get more of the emphasized  
Rear wave cancellation requires  
corrective equalization beginning at  
500 Hz and increasing to roughly 12dB  
at 100 Hz. Primary resonance affects  
this response as well, because the  
speaker is effectively out of control at  
primary resonance. A notch filter works  
well to negate the effects of this  
typically 12dB resonance. The decision  
of resonance tuning and rear wave  
cancellation compensation, combined  
in balance with the high frequency roll-  
off point, is a system decision based  
on the sonic properties of the speaker  
itself.  
In order to assure a high level of  
performance with all types of preamps  
and cables, the MONOLITH IIIx CROSS-  
OVER has a high input impedance, low  
output impedance buffer for its first  
stage. Futhermore, since there is no  
substitute for isolation to prevent  
various filter sections from interacting  
with each other (normally the high  
pass and low pass filters), the MONO-  
LITH IIIx CROSSOVER has a separate  
buffer for the high-pass and the low-  
pass audio path.  
percussive effect of rock music. The  
last priority, “classic European”,  
consists of a dry, clean, very tight bass  
structure. It can be accomplished by  
resetting the frequency control to 30  
Hz and turning down the boost/cut  
control. At this point, you will still have  
deep and extended bass, but it will be  
slightly rolled off to give you a very tight,  
defined performance level.  
These buffers are designed using two  
complimentary J-FET devices per  
buffer, strapped in unity gain, voltage  
follower topology. Two additional  
bipolar devices are used as current  
sources only, enabling the J-FETs to  
be completely current biased. This  
complimentary J-FET buffer is used  
repeatedly throughout the crossover,  
except for the output stage which  
requires gain.  
The MONOLITH IIIx CROSSOVER's high-  
pass pathway utilizes three separate  
filter sections; one for raising energy  
between 100 Hz and 500 Hz, empha-  
sizing 100 Hz (referred to as a shelving  
filter), another for decreasing energy at  
the speaker resonance (notch filter)  
and a third high-pass filter.  
In the final evaluation, your ears will  
determine where these controls  
should be positioned. They have been  
established for your flexibility and use  
and can be used much like an accurate  
bass/room equalizer. So don't be  
afraid to experiment and have fun!  
Page16  
Monolith III User's Manual  
 
The woofer has another set of require-  
ments based upon its inherent dis-  
placement limitations. In order to  
static element demands that the woofer To prevent subsonic energy from taxing  
be a fast, quick-to-change, well damped the listener, room, and driver, a sub-  
driver so that it will blend with the  
sonic high-pass filter is necessary. A  
recreate strong low frequency energy  
using a dynamic cone drive, a high “Q”  
driver in a large tuned (usually ported)  
box is required. The trade-off with this  
approach is poor speed, acceleration,  
and damping of the woofer driver. The  
superior performance of the electro-  
electrostatic transducers characteristics third filter is reserved for low-pass filter  
properly. This is best obtained by using  
a low “Q”, low mass, small box design.  
However, to maintain good low fre-  
quency response with this approach,  
low frequency boost is required. Here,  
again, a shelving filter is used.  
operation. The characteristics of  
frequency and “Q” of each filter is  
affected by component value selection  
within each filter section.  
Figure 7: MONOLITH IIIx CROSSOVER block diagram of circuit.  
Page17  
Monolith III User's Manual  
 
Room Acoustics  
Your Room  
Terminology  
This is one of those areas that requires  
a little background to understand and  
some time and experimentation to  
obtain the best performance from your  
system.  
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 “tubby bass”. For instance,  
100Hz represents a 10' wavelength. Your room will reinforce that specific  
frequency if one of the dominant dimensions is 10'. 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 get away from this phenomenon.  
Your room is actually a component and  
an important part of your system. This  
component is a very large variable and  
can dramatically add to, or subtract  
from, a great musical experience,  
Reflective Surfaces. The hard surfaces of your room, particularly if close to  
your speaker system, will reflect those 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  
can occur.  
depending on how well you attend to it.  
All sound is composed of waves. Each  
note has its own wave size, with the  
lower bass notes literally encompass-  
ing from 10' to as much as 40'! Your  
room participates in this wave experi-  
ence like a 3 dimensional pool with  
waves reflecting and becoming  
enhanced depending on the size of the  
room and the types of surfaces in the  
room.  
Near Field Reflections. Those reflective surfaces of the room that are the  
closest to your speaker system, particularly if they are hard surfaces, can  
reflect the musical energy back into the room, confusing the imaging and  
tonal balance of your system. Excessive brightness can result from this  
condition and diffuse, ill defined imaging can easily occur if too many  
surfaces near your speakers are hard and sharp in their relative angle to  
your system.  
Remember, your audio system can  
literally generate all of the information  
required to recreate a musical event in  
time, space, and tonal balance. The  
purpose of your room, ideally, is to not  
contribute to that information. However,  
every room does contribute to the  
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.  
sound and the better speaker manufac-  
turers have designed their systems to  
accommodate this phenomenon.  
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  
“onenotesounds.  
Let’s talk about a few important terms  
before we begin.  
Clap your hands. Can you hear an instant echo respond back ? You’ve  
got near-field reflections. Stomp your foot on the floor. Can you hear a  
“boom”? You’ve got standing waves or large panel resonances such as a  
poorly supported wall. Put your head in a small cavity area and talk loudly.  
Can you hear a booming? You’ve just experienced a cavity resonance.  
Page18  
Monolith III User's Manual  
 
Rules of Thumb  
Bipolar Speakers and Your Room  
Hard vs. Soft Surfaces. If one surface of your  
room (wall, floor, ceiling) is hard, a good  
rule of thumb suggests to try to have the  
opposing surface soft. So, if you have a  
hard wall of glass or paneling on one side  
of the room, it is best to have drapery or wall  
hangings on the opposing wall. If you have  
a hard ceiling, it generally is a good idea to  
have a soft floor of carpeting or area rugs.  
Large, soft furniture also counts to help  
damp a highly reflective room.  
Martin-Logan electrostatic loudspeakers are known as bipolar 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 back wall. Your Monoliths have been designed to be placed 2 to 3 feet  
from the back wall 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 back wall can allow you to get  
the best combination of depth of bass and tonal balance.  
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.  
The mid-range and high frequencies can also be affected, but in a  
different way. The timing of the first wave as it is first radiated 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 imaging and, consequently result in blurred imaging and exces-  
sive 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.  
Vertical Dispersion  
Break-up Objects. Objects with complex  
shapes, such as bookshelves, cabinetry,  
and multiple shaped walls can help to  
break up those sonic gremlins and diffuse  
any dominant frequencies.  
As you can see from the illustrations, your Monolith III speakers project a  
controlled dipersion pattern. Each Monolith is a four foot line source  
beginning two feet above floor level. This vertical dispersion profile  
minimizes interactions with the floor and the ceiling.  
Solid Coupling. Your loudspeaker system  
generates frequency vibrations or waves  
into the room. This is how it creates sound.  
Those vibrations will vary from 20 per  
second to 20,000 per second. If your  
speaker system is not securely planted on  
the floor or solid surface, it can shake as it  
produces sound, and consequently the  
sound can be compromised. If your  
Horizontal Dispersion  
Your Monoliths launch a 30 degree dispersion pattern when viewed from  
above. This horizontal dispersion field gives you a choice of good seats for  
the performance while minimizing interactions with side walls.  
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  
and, consequently small refined adjustments can result in noticeable  
sonic improvements.  
speaker is setting on the carpet and only  
foot gliders are used, the bass can be ill  
defined and even boomy. Additionally, the  
imaging can be poorly located and diffuse if  
the system is not on solid footing.  
Page19  
Monolith III User's Manual  
 
Room Acoustics  
Dispersion Concepts  
Historically, most attempts to achieve  
surface, we create the effect of a  
In the field of loudspeaker design, it is  
common knowledge that as the wave  
becomes progressively smaller than the  
transducer producing it, the dispersion  
of that wave becomes more and more  
narrow, or directional. This occurs as  
long as the transducer is a flat surface.  
smooth dispersion from large flat panel  
transducers resulted in trade-offs. After  
exhaustive testing of these different  
solution attempts, we found an ele-  
gantly simple, yet very difficult to execute gentle curve on our products.  
solution. By curving the radiating  
horizontal arc. This allows the engi-  
neers at Martin-Logan to control the  
high frequency dispersion pattern of our  
transducers. That is why you see the  
Ascanbeseen,pointsourceconcepts  
invite a great deal of room interaction.  
While delivering good frequency re-  
sponse to a large listening audience,  
imagingisconsequentlyconfusedand  
blurred.  
Eventhoughtheysufferfrom"venetian  
blind" effect, angled multiple panel  
speakers can deliver good imaging,  
but only to specific spots in the listen-  
ingarea.  
A controlled 30-degree cylindrical  
wave-front, which is a Martin-Logan  
exclusive, offers optimal sound distri-  
bution with minimal room interaction.  
The result is solid imaging with a wide  
listeningarea.  
Page20  
Monolith III User's Manual  
 
Placement  
General Placement  
The Back Wall  
Near-field reflections can also occur from your back wall. If  
your listening position is close to a back wall, these reflec-  
tions can cause problems and confuse the quality of  
imaging. Actually it is better for the back wall to be soft than to  
be bright. If you have a hard back wall and your listening  
position is close to it, experiment with devices that will soften  
and absorb information, ie: wall hangings and possibly even  
sound absorbing panels.  
Start by making certain that both speakers are the same  
distance from the walls behind or beside them and that their  
“toe-in” angle is the same. At this time you may want to enlist  
the help of a friend or family member to assist you.  
It is generally true that, as you move your speakers farther  
forward into the listening environment, you will derive more  
spaciousness from them. Toeing them toward the middle of  
the listening area will enhance brightness.  
As you place and listen, keep in mind that tight bass and  
clear resolution indicate proper placement and that the  
acoustical image is in focus. Don’t hesitate to experiment,  
but give each new combination of positions a thorough test.  
The time and effort you invest here will be well spent.  
The Front Wall  
The wall behind your speakers should not be extremely hard  
or soft. For instance, a pane of glass will cause reflections,  
brightness, and confused imaging. Curtains, drapery, and  
objects such as bookshelving can be placed along the back  
wall to tame an extremely hard surface. A standard sheet  
rock or textured wall is generally an adequate back surface if  
the rest of the room is not too bright and hard.  
By now your speakers should be placed approximately 2 to 3  
feet from the back wall and at least 1 to 2 feet from the side  
walls. Your sitting distance should be further than the  
distance between the speakers themselves. What you are  
trying to attain is the impression of good center imaging and  
stage width.  
Sometimes walls can be too soft. If the entire front wall  
consists of only heavy drapery, your system can literally  
sound too soft or dull. You will hear dull, muted music with  
little ambience. Harder room surfaces will actually help in  
this case.  
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.  
The front surface should, optimally, be one long wall without  
any doors or openings. If you have openings, the reflection  
and bass characteristics from one channel to the other can  
be different.  
Now that you have positioned your speaker system, spend  
some time listening. Wait to make any major changes in  
your initial set-up for the next few days as the speaker  
system itself will change subtly in its sound. Over the first 20  
hours of play the actual tonal quality will change slightly with  
deeper bass and more spacious highs resulting.  
The Side Walls  
The same requirements exist for side walls. Additionally, a  
good rule of thumb is to have the side walls as far away from  
the speaker sides as possible, minimizing near field side  
wall reflections. Sometimes, if the system is bright or the  
imaging is not to your liking, and the sidewalls 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.  
After a few days of listening you can begin to make refine-  
ments and hear the differences of those refinements.  
Page21  
Monolith III User's Manual  
 
Placement  
Experimentation  
A Final Word  
Imaging.  
In their final location, your Monoliths  
Toe-in.  
Final Placement.  
Now you can begin to experiment.  
First begin by toeing your speakers  
in towards the listening area and  
then toeing them out. You will  
notice that the tonal balance  
changes ever so slightly. You will  
also notice the imaging changing  
ever so slightly. 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.  
After obtaining good wall treat-  
ments and attaining proper angle,  
begin to experiment with the  
distance from the back wall. Move  
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 tightened, that is a  
should have a stage width some-  
what wider than the speakers  
themselves. On well recorded  
music, the instruments should  
extend beyond the edges of each  
speaker to the left and to the right,  
yet a vocalist should appear directly  
in the middle. The size of the  
instruments should be neither too  
large nor too small. Additionally,  
you should find good clues as to  
stage depth.  
superior position. Move the  
speakers back six inches from the  
initial set-up position. Again, listen  
to the imaging and bass response.  
There will be a position where you  
will have pin-point imaging and  
good bass response. That position  
becomes the point of the optimal  
placement from the back wall.  
Bass Response.  
Experimenting with the toe-in will  
help in terms of tonal balance. 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 modify a soft or bright room.  
Your bass response should neither  
be one note nor should it be too  
heavy. It should extend fairly deep  
to all but the deepest organ  
passages yet it should 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 any booming or  
thudding.  
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 pin-point focusing.  
Tilting the Speakers.  
(Backwards and Forwards)  
As can be seen from the diagrams  
in the Room Acoustics section of  
this manual, the vertical dispersion  
is directional above and below the  
stat panel itself. If you sit in a tall  
chair, you may get better perform-  
ance by tilting the speakers back  
so that the high frequencies are on  
axis with your ears. Otherwise, with  
a normal sofa and normal listen-  
ing, tilt the speakers only slightly  
back if not straight up. Make sure,  
when listening, that the vertical  
alignment, distance from the back  
wall, and toe in is exactly the same  
from one speaker to the other. This  
will greatly enhance the quality of  
your imaging.  
Tonal Balance.  
Your ideal listening position and  
speaker position will be deter-  
mined by the following:  
Voices should be natural and full,  
cymbals should be detailed and  
articulate yet not bright and  
piercing, pianos should have a nice  
transient characteristic and deep  
tonal registers as well. If you  
cannot attain these virtues, re-read  
the section on Room Acoustics.  
This will give you clues on how to  
get closer to those ideal virtues.  
1. Tightness and extension of  
bass response.  
2. The width of the stage.  
3. The pin-point focusing of  
imaging.  
Once you have found the best of all  
three of those considerations, you  
will have your best speaker  
location.  
Page22  
Monolith III User's Manual  
 
General Information  
Associated Equipment Care  
Enjoy Yourself  
The MONOLITH III is a very refined  
speaker and, as such, benefits from  
careful set-up. With the information in  
this manual in mind, you will find, over  
your months of listening, that small  
changes can result in demonstrable  
differences. As you live with your  
speakers, do not be afraid to experi-  
ment with their positioning until you  
find the optimal relationship between  
your room and your speaker system.  
Your efforts will be rewarded.  
Your Martin-Logan Dealer was  
The Martin-Logan Monolith has been  
carefully selected by our company  
because they are knowledgeable,  
experienced and dedicated to musical  
excellence and customer satisfaction.  
carefully designed and precisely  
engineered. With a little care you can  
rest assured that they will continue to  
look as good as they sound for years  
to come.  
They have the ability to help you  
acquire the very best in audio equip-  
ment. They are likely to choose that  
equipment from among a small group  
of manufacturers that are committed to  
the faithful recreation of music.  
Do not spray any cleaning solutions on  
the electrostatic element, as this could  
impair the speakers performance.  
Dust may be removed with a brush  
attachment on a vacuum cleaner or  
you may blow it off with compressed  
air. Silicone dusting sprays, abrasive  
or solvent-based cleaners should not  
be used on any portions of the  
speaker.  
You are now armed with the basics of  
room acoustics and the specific  
fundamentals of the MONOLITH III  
loudspeaker system. Enjoy yourself  
and happy listening.  
Your new MONOLITH III speakers are  
quite honest in revealing the relative  
strengths and weaknesses of the  
equipment used with them. While the  
Monolith will bring to life the sonic  
delights of state-of-the-art compo-  
nents, it will with equal clarity bring out  
any system flaws. This does not mean  
that expensive equipment is a  
Solid Footing  
It is best to have a the Monoliths  
coupled firmly with the floor. After living  
and experimenting with the placement  
of your Monoliths, you should use the  
spikes included in your owners kit.  
Bass response will tighten and  
imaging will become more coherent,  
fixed and detailed. It is best not to  
implement the spikes however, until  
you have decided upon the final  
placement of the speaker, as they can  
damage the floor if the speaker is  
moved.  
prerequisite to good sound from the  
Monolith, but rather that the equipment  
must be wisely selected and setup  
with care. The rewards will be well  
worth the effort.  
As time goes by, you may find it  
instructive to discuss with your dealer  
the merits and advantages of carefully  
upgrading certain pieces of your  
associated equipment.  
Page23  
Monolith III User's Manual  
 
The Electrostatic Concept  
How is it that music can be recreated by diaphragm is what actually moves to  
signals are changed into two high-  
voltage signals that are equal in  
something that you are able to see  
through? Electrostatic energy makes  
this possible.  
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 dia-  
phragm. The spacers provide the  
diaphragm with a fixed distance in  
which to move between the stators.  
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 simultane-  
ously with and against the diaphragm,  
consequently moving it back and forth,  
producing music. This technique is  
known as push-pull operation and is a  
Where the world of traditional loud-  
speaker technology deals with cones,  
domes, diaphrams, and ribbons that  
are moved with magnetism, the world  
of electrostatic loudspeakers deals with As your amplifier sends music signals  
charged electrons attracting and  
repelling each other.  
to an electrostatic speaker, these  
To fully understand the electro-  
static concept , some back-  
ground information will be  
helpful. Remember when you  
learned, in a science or physics  
class back in high school, that  
like charges repel each other  
and that opposite charges attract  
each other? Well, this principle is  
the foundation of the electrostatic  
concept.  
An Electrostatic Transducer  
Diaphragm  
Spacer  
Stator  
An electrostatic transducer  
consists of three pieces: the  
stators, the diaphragm and the  
spacers. (See Figure 8.) The  
Figure 8. Cut away view of an electrostatic transducer.  
Notice the simplicity due to minimal parts usage.  
Page24  
Monolith III User's Manual  
 
major contributor to the sonic purity of  
the electrostatic concept due to its  
exceptional linearity and low distortion.  
possible. When you look at the prob-  
lems of traditional electromagnetic  
drivers, you can easily see why this is  
so beneficial .  
cone or dome is just "along for the ride".  
The basic concept of these drivers  
require that the cone or dome be  
perfectly rigid, damped and close to  
massless. Unfortunately these condi-  
tions are not available in our world  
today.  
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  
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  
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  
9.). These pieces, when  
combined with the high mass of  
the cone or dome materials  
used, make it an extremely  
An Electromagnetic Transducer  
complex unit with many weak-  
nesses and potential for failure.  
These faults contribute to the  
high distortion products found in  
this type of driver and is a  
Surround  
Cone  
Dust Cap  
Voice Coil Former  
tremendous disadvantage  
when you are trying to change  
Spider(Suspension)  
motion as quickly and as  
accurately as a loudspeaker  
must (40,000 times per  
second!).  
Basket Assembly  
MagnetAssembly  
MagneticGap  
Magnet  
Voice Coil  
Figure 9. Cut away view of a typical moving coil driver.  
Notice the complexity due to the high number of parts.  
Page25  
Monolith III User's Manual  
 
Martin-Logan Exclusives  
1. Full Range Operation  
The most significant advantage of  
Martin-Logan's exclusive transducer  
technology reveals itself when you look  
at examples of other loudspeaker  
products on the market today.  
full range of frequencies. Instead, these  
a division of the complex musical signal  
into the separate pieces (usually highs,  
mids, and lows) that each specific  
driver was designed to handle. Unfortu-  
nately, due to the phase relationships  
that occur within all crossover networks  
and during the acoustical recombina-  
tion process, nonlinearities and severe  
degradation of the music signal takes  
place in the ear's most "critical zone".  
drivers must be designed to operate  
within narrow, fixed bandwidths 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.  
The MONOLITH III uses no crossover  
networks above 125 Hz because they are  
not needed. The MONOLITH III consists  
of a single, seamless electrostatic  
membrane reproducing all frequencies  
above 125 Hz simultane-  
In order to use multiple drivers, a  
crossover network is enlisted to attempt See Figure 10.  
ously. How is this possible?  
The MONOLITH III's electro-  
static transducer can single-  
handedly reproduce all  
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.  
Conventional Loudspeaker  
frequencies above 100 Hz  
simultaneously. So, you  
have, in one transducer, the  
ability to handle, in elegant  
simplicity, the critical  
Tweeter  
Critical Zone  
250 - 20kHz  
Midrange  
frequencies above 100 Hz.  
Woofer  
The electrostatic transducer  
of the Monolith 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 pre-  
served by some type of  
storage media. The MONO-  
LITH III's electrostatic trans-  
ducer transforms electrical  
energy from your amplifier  
into acoustical energy.  
Due to the limitations of  
electromagnetic drivers, no  
single unit can reproduce the  
The crossover phase  
discontinuities that are  
associated with traditional  
tweeter, midrange, and  
woofer systems are elimi-  
nated. This results in a  
dramatic improvement in  
imaging and staging  
performance due to the  
minutely accurate phase  
relationship of the full-range  
panel wave launch.  
Martin-Logan MONOLITH III  
MONOLITH III  
Electrostatic  
250 - 20kHz  
Transducer  
Critical Zone  
Woofer  
Figure 10. Illustrates how a conventional speaker system  
must use a crossover network that has negative affects  
on the musical performance unlike the MONOLITH III which  
needs no crossover networks in the "critical zone".  
Page26  
Monolith III User's Manual  
 
2. Curvilinear Line  
Source  
3. Hybrid Technology  
5. Transducer Integrity  
When Martin-Logan introduced the  
Monolith back in 1982, it was the first  
company to commercially recognize the  
performance potential available by  
mating the air-moving capabilities of a  
All Martin-Logan transducers begin with  
two pieces of high grade, cold rolled  
steel. The rear stator is manufactured  
from 16 gauge material while the front  
stator from 18 gauge. These steel  
Since the beginning of Audio, achieving  
smooth 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.  
dynamic woofer with the inherent speed pieces are then custom perforated and  
and accuracy of an electrostatic panel.  
insulated with an exotic nylon compos-  
ite coating. This proprietary coating  
insulates the stator to 3 times its actual  
needed working voltage and gives the  
Monolith a wide margin of safe opera-  
Since then, refinements in the actual  
driver assemblies, crossover compo-  
nents, and materials used in the  
construction of our hybrid speakers have tion. In addition to the electrical insula-  
brought this concept to its full potential.  
Full range electrostats have long been  
one of the most problematic transduc-  
ers 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 compro-  
mise in sound quality.  
tion properties, this coating also  
provides the Monolith with a durable,  
attractive finish that dampens the steel  
to prevent ringing. These pieces are  
then sandwiched with our exclusive  
vapor deposited diaphragm and  
spacers into a curved geometry and  
bonded together with aerospace  
adhesives whose strength exceeds that  
of welding.  
4. Vapor Deposited  
Film  
The diaphragm material used in all  
Martin-Logan speakers employs an  
extremely sophisticated conductive  
surface that has been vapor deposited  
on the polymer surface at an atomic  
level. Copper oxide and palladium have  
been vaporized and electrostatically  
driven into the surface of the polymer  
film in a vacuum chamber. This process  
allows an optically transparent surface  
adding no mass to the diaphragm that  
is extremely uniform in its surface  
resistivity characteristics. This uniform  
surface resistivity controls the electro-  
static charge on the diaphragm surface  
and regulates its migration. As a result,  
no discharging or “arcing” can occur.  
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 dia-  
phragm remained uncompromised.  
After creating this technology, we  
When all of these various techniques  
are combined, we get a transducer that  
is attractive, durable, highly rigid, well  
dampened, and neutral.  
developed the production capability to  
bring this technology out of the labora-  
tory 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 Martin-  
Logan products.  
Page27  
Monolith III User's Manual  
 
Questions  
Could my children, pets, or myself  
be shocked by the high-voltage  
present in the electrostatic panel?  
Should I unplug my Monoliths during  
a thunderstorm?  
Will excessive smoke or dust cause  
any problems?  
Yes. Or before. It’s a good idea to  
disconnect all of your audio/video  
components during stormy weather.  
Exposure to excessive smoke or dust  
may potentially affect the performance  
of the electrostatic membrane. When  
not in use, you should unplug the  
speaker and cover with the plastic  
bags that the speakers were originally  
packed in.  
No. High voltage with low current is  
not dangerous. As a matter of fact, the  
high-voltage present in our speakers  
is10 times less than the static  
electricity that you generate when you  
take off a sweater. (About 30,000  
volts!)  
Will my electric bill go ‘sky high’ by  
leaving my speakers plugged in all  
the time?  
If my child punctured the diaphragm  
with a pencil, stick, or similar item.,  
how extensive would the damage to  
the speaker be?  
What size of an amplifier should I  
use with the Monoliths?  
No. A pair of Monoliths draw about 5  
watts maximum.  
We recommend an amplifier with 100  
to 200 watts per channel for most  
applications.  
Is there likely to be any interaction  
between the Monoliths and the  
television in my Audio/Video  
system?  
You should probably replace the  
electrostatic element. However, this  
depends upon the extent of the  
damage.  
Do I need an amplifier with high  
current capability?  
Actually, there is less interaction  
between a television and an electro-  
static speaker than between a  
television and a conventional system.  
The magnets in conventional speak-  
ers do interact with televisions tubes.  
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 exposure to sunlight affect the  
life or performance of the Monolith?  
No. The Monolith's impedance  
characteristics do not require that a  
high current amplifier be used.  
However, it is important that the  
amplifier be stable operating into  
varying impedance loads.  
We recommend that you not place  
your Monoliths in direct sunlight as  
the ultraviolet (UV) rays from the sun  
can cause deterioration of the  
electrostatic membrane. However,  
small exposures to UV should not  
cause a problem.  
Page28  
Monolith III User's Manual  
 
Troubleshooting  
No Output.  
Lack of Bass  
Check that all your system components are turned on.  
Check your speaker wires and connections.  
Check all interconnecting cables.  
Check your speaker wires. Is the polarity correct?  
Poor Imaging  
Check placement. Are both speakers the same dis-  
tance from the walls? Do they have the same amount  
of toe-in? Try moving the speakers away from the back  
and side walls.  
Weak Output, Loss of Highs.  
Check the power cord. Is it properly connected to the  
speaker?  
Check the polarity of the speaker wires. Are they  
connected properly?  
If you are bi-amplifiying, check your high frequency  
amplifier. Is it functioning properly?  
Popping and Ticking Sounds, Funny Noises  
Exaggerated Highs, Brightness.  
These occasional noises are harmless and will nut hurt  
your audio system or your speakers. All electrostatic  
speakers are guilty of making odd noises at one time or  
another.  
Check the toe-in of the speakers. Read Room Place-  
ment for more information.  
These noises may be caused by dirt and dust particles  
collecting on the speaker, by high humidity or by AC line  
fluctuations that may occur in your area.  
Muddy Bass  
Check placement. Try moving the speakers closer to  
the back and side walls.  
Dirt and dust may be vacuumed off with a brush  
attachment connected to your vacuum cleaner or you  
may blow them off with compressed air.  
Check the type of feet being used. Try attaching the  
coupling spikes.  
DO NOT SPRAY ANY KIND OF CLEANING AGENT  
ON OR IN CLOSE PROXIMITY TO THEM.  
If you are using the IIIx CROSSOVER, adjust the bass  
contour controls until you get the desired response  
Page29  
Monolith III User's Manual  
 
Glossary  
AC. Abbreviation for alternating  
current.  
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 loud-  
speaker and is the major cause  
of loudspeaker component  
failure.  
Driver. See transducer.  
Active crossover. Uses active  
devices (transistors, IC’s,  
tubes) and some form of power  
supply to operate.  
Dynamic Range. The range between  
the quietest and the loudest  
sounds a device can handle  
(often quoted in dB).  
Amplitude. The extreme range of a  
signal. Usually measured from  
the average to the extreme.  
Efficiency. The acoustic power  
delivered for a given electrical  
input. Often expressed as  
Crossover. An electrical circuit that  
divides a full bandwidth signal  
into the desired frequency bands  
for the loudspeaker components.  
decibels/watt/meter (dB/w/m).  
Arc. The visible sparks generated by  
an electrical discharge.  
ESL. Abbreviation for electrostatic  
loudspeaker.  
Bandwidth. The range of frequencies  
within a radiation band required  
to transmit a particular signal.  
dB (decibel). A numerical expression  
of the relative loudness of a  
Headroom. The difference, in deci-  
bels, between the peak and RMS  
levels in program material.  
sound. The difference in decibels  
between two sounds is ten times  
the common logarithm of the ratio  
of their power levels.  
Bass. The lowest frequencies of  
sound.  
Hybrid. A product created by the  
marriage of two different tech-  
nologies. Meant here as the  
Bi-Amplification. Uses an electronic  
crossover or line-level passive  
crossover and separate power  
amplifiers for the high and low  
frequency loudspeaker drivers.  
DC. Abbreviation for direct current.  
combination of a dynamic woofer  
with an electrostatic transducer.  
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.  
Hz (Hertz). Unit of frequency equiva-  
lent to the number of cycles per  
second.  
Capacitance. That property of a  
capacitor which determines 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.  
Imaging. To make a representation or  
imitation of the original sonic  
event.  
Diaphragm. A thin flexible membrane  
or cone that vibrates in response  
to electrical signals to produce  
sound waves.  
Impedance. The total opposition  
offered by an electric circuit to the  
flow of an alternating current of a  
single frequency. It is a combina-  
tion of resistance and reactance  
and is measured in ohms.  
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.  
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.  
Remember that a speaker’s  
impedance changes with  
frequency, it is not a constant  
Page30  
Monolith III User's Manual  
 
value.  
phase reinforce each other; those  
out of phase cancel.  
Pink noise. A random noise used in  
measurements, as it has the  
same amount of energy in each  
octave.  
reference for the moving dia-  
phragm in a planar speaker.  
THD. Abbreviation for total harmonic  
distortion. (See Distortion.)  
Inductance. The property of an  
electric 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.  
TIM. Abbreviation for transient  
intermodulation distortion. (See  
Distortion.)  
Polarity. The condition of being  
positive or negative with respect  
to some reference point or object.  
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.  
Inductor. A device designed primarily  
to introduce inductance into an  
electric circuit. Sometimes called  
a choke or coil.  
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.  
Linearity. The extent to which any  
signal handling process is  
accomplished without amplitude  
distortion.  
Transient. Applies to that which lasts  
or stays but a short time. A  
change from one steady-state  
condition to another.  
Resistance. That property of a  
conductor by which it opposes  
the flow of electric current,  
Midrange. The middle frequencies  
where the ear is the most  
sensitive.  
resulting in the generation of heat  
in the conducting material,  
usually expressed in ohms.  
Transmit. To cause sound to pass  
through air or some other  
medium.  
Passive crossover. Uses no active  
components (transistors, 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 cross-  
overs consist of capacitors,  
inductors and resistors.  
Resistor. A device used in a circuit  
primarily to provide resistance.  
Tweeter. A small drive unit designed  
to produce only high frequencies.  
Resonance. The effect produced  
when the natural vibration  
Wavelength. The distance measured  
in the direction of progression of  
a wave, from any given point  
frequency of a body is greatly  
amplified by reinforcing vibrations  
at the same or nearly the same  
frequency from another body.  
characterized by the same phase.  
Phase. The amount by which one  
sine wave leads or lags a second  
wave of the same frequency. The  
difference is described by the  
White noise. A random noise used in  
measurements, as it has the  
same amount of energy at each  
frequency.  
Sensitivity. Volume of sound deliv-  
ered for a given electrical input.  
term phase angle. Sine waves in  
Stator. The fixed part forming the  
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.  
Page31  
Monolith III User's Manual  
 
$ 3.00  
2001 delaware street, p.o. box 741, lawrence, kansas 66044, phone: 913.749.0133, fax: 913.749.5320  
© 1989 Martin-Logan Ltd. All rights reserved.  
 

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