AKG WMS 40 SINGLE/DUAL User manual

WMS 40
WMS 400
WMS 4000
Wireless
Microphone
Systems
Everything you've always wanted to know
about AKG WIRELESS TECHNOLOGY.

As more and more affordable wireless
equipment became available, the
demand for high quality single and multi-
channel wireless systems for sound com-
panies, conference centers, public buil-
dings, and live sound grew sharply, too.
AKG responded to this trend early on,
developing a specific line of products
and accessories that provides a profes-
sional solution for every application.
This brochure explains the way wireless
systems work to provide a better under-
standing of how to make optimum use of
RF technology in day-to-day work. It con-
tains many helpful tips and tricks for
both professionals and first-time users.
Wireless equipment from AKG will provi-
de a professional solution for any appli-
cation. This brochure makes it easier to
get the best possible results.
A PIONEER IN ACOUSTICS FOR OVER 50 YEARS
WIRELESS TECHNOLOGY FOR THE FUTURE
www.akg.com 1
“When it comes to studio, broadcast, or live sound equip-
ment, choose AKG. The engineering competence and
worldwide reputation of the AKG brand give you the con-
fidence of using equipment meeting the highest stan-
dards of quality and reliability.”
Dr. Hugo Lenhard-Backhaus, CEO, AKG Vienna
For more than five decades, AKG has been
a leading manufacturer of studio micro-
phones, broadcast and live sound equip-
ment, as well as headphones to the hig-
hest standards of quality and reliability.
The resulting experience and engineering
know-how are the foundation of the uni-
que sound of AKG products as well as the
reputation and popularity of the legendary
AKG brand. Today, AKG products are avai-
lable throughout the world and have beco-
me a standard in many radio and TV stu-
dios.
Did you know that according to the 1990
Billboard Survey every US recording stu-
dio uses at least one AKG product?
Should you find no product for your specific application in this brochure, please post to the
AKG Forum at www.akg.com.
We also appreciate any suggestions for improvements, new products, or other ideas you may
post to our Microphone Forum.
AKG Facts & Figures:
• Established in Austria in 1947
• Founders: Rudolf Görike
and Ernst Pless
• AKG grew from a two-man company
into a multinational company
• AKG has applied for more than
1,400 patents worldwide
• AKG is a leading audio manufacturer
with one of the most advanced
acoustics labs in Europe
AKG PREFACE

How it all started …
A word to skeptics from the outset: the
history of AKG is simply too good to have been
just made up!
1945: In a setting reminiscent of “The Third
Man”, two men who had occasionally done
business with one another before World War II
met up again. They discovered that people
sought distraction from the ruins around them
at the movies, but that most of Vienna’s movie
theaters had either been bombed or plundered.
Thus there was a pressing need for good thea-
ter equipment. And so it was that Rudolf Görike
and Ernst Pless conceived a new idea: “Let us
go into business together.” This was the begin-
ning of a success story that has already lasted
over 50 years.
Rudolf Görike started manufacturing movie pro-
jectors and loudspeakers, whilst Ernst Pless
delivered their growing customer base by bicy-
cle and rucksack. As the volume of orders grew,
they even resorted to using a good old-fashioned
wheelbarrow! Their first customers did not have
any hard currency to pay them with, but they
did have pork, butter and cigarettes – fresh from
the black market and in great demand.
1947: The two pioneers decided to set up a
company. Once all the preparations had been
made, the company set up office in a basement
in a suburb of Vienna and hired a staff of five
employees.
Initially the range included products such as
exposure meters, car horns, intercom systems,
carbon capsules and auxiliary handsets for tele-
phones, pillow loudspeakers, and many other
appliances that seem curious to us today. The
product range was continually adapted to meet
demand.
Meanwhile Rudolf Görike, a gifted drawer
and painter, created a logo for the company. It
was he who designed the products, bubbling
over with new ideas and applying for several
patents in quick succession. Before World War
II, he had been involved with microphones as
development manager with the firm of “Henry
Radio”. His hobby remained his profession, and
he was finally able to put his ideas for new tech-
nologies into practice.
The first AKG microphones went into service
the same year, mainly with radio stations, at
theaters, cabarets and jazz clubs. The AKG Dyn
Series, for example, was one such development:
painstakingly assembled by hand, it would be
simply unaffordable today.
A PIONEER IN ACOUSTICS FOR OVER 50 YEARS
AKG - A LEGENDARY BRAND
2www.akg.com
The logo
The first AKG logo with three overlapping rings (symboli-
zing the typical omnidirectional polar pattern of the time)
was designed by company founder Rudolf Görike. With the
introduction of the AKG D 12 – the first microphone with a
cardioid polar pattern – in 1953, the three rings were
replaced with three cardioids. Apart from slight modifica-
tions, this logo has remained in use to this day, and is the
guarantee of AKG’s legendary quality the world over.
Die DYN Series
AKG developed its first dynamic microphones in 1946. With an
annual production of 500 to 600 units, every single component
was manufactured by hand and a wide variety of designs pro-
duced in the “DYN” series – DYN 60, DYN 60 G, DYN 60 K (see
illustration), DYN 60 Studio, etc. The original microphones in
this series have since become collectors’ items.
K 120 DYN
The first AKG headphones bearing the designation K 120 DYN
were launched in 1949. They were equipped with a Trolitul dia-
phragm of molded granulate, since foils were not yet available.
At the time AKG had only one winding machine and one gluing
machine.
The founders: Dr. Rudolf Görike and Ing. Ernst Pless
“The past is of no interest to me. I always look ahead – to the
future…” commented AKG co-founder Rudolf Görike some years
ago. At the time he was already over 80 years old!
AKG HISTORY

www.akg.com 3
The early products
In 1945 the company began supplying
technical equipment such as movie projec-
tors and loudspeakers to Vienna movie
theaters. The PC 2535 G horn-loaded thea-
ter loudspeaker with a cardboard dia-
phragm, for instance, was manufactured
in a living room.
The company name
The founders considered calling their com-
pany “Phonophot”, but because of its simi-
larity with another name, they opted for
“Akustische- und Kino-Geräte“, or AKG for
short. Acoustic equipment became more
and more predominant, and in 1965 thea-
ter equipment was dropped from the range
entirely and the name changed to “AKG
Acoustics”.
1945 Rudolf Görike and Ernst Pless start supplying Vienna movie theaters with
equipment
1947 Rudolf Görike and Ernst Pless set up AKG
1953 World’s first single-diaphragm dynamic cardioid microphone (D 12)
Manufacture of the famous C 12 large-diaphragm condenser microphone
Founding of a German subsidiary
1954 World’s first single-diaphragm dynamic cardioid microphone
1955 World’s first remote-controlled multipattern dynamic microphone (D 36)
1956 Professional cardioid microphone with variable rear sound entry to reduce
proximity effect (D 24, D 19)
1959 World’s first supra-aural headphones (K 50)
1960 Design of the first professional small-sized condenser microphone (C 60)
1965 Manufacture of movie theater equipment discontinued in favor of audio pro-
ducts
1966 World’s first two-way cardioid microphones (D 202, D 224)
World’s first wide-band ultrasonic transducer (CK 40)
1969 Founding of a British subsidiary
Design of the first modular condenser microphone
(CMS system including C451, CK 1, etc.)
1970 World’s first portable professional reverberator (BX 20)
1973 Her Majesty’s Post Office issues a 3 p stamp to commemorate the BBC's 50th
anniversary showing the BBC’s standard microphones, all of them AKG models
1974 AKG applies for its thousandth patent
1975 Introduction of AKG multidiaphragm headpones (K 240)
1976 Introduction of AKG TS System (Transversal Suspension) for phono cartridges
(P8 ES etc.)
1977 Miniature studio condenser microphone with 6 mm capsule and self-polarized
diaphragm
New compact reverberation unit (BX 5)
1978 World’s first dynamic/electrostatic headphones (K 340)
1979 World’s first modular digital time delay unit (TDU 7000)
Vocal microphones combining extreme ruggedness with studio-standard
sound quality (D 300 Series)
Founding of a Japanese subsidiary
1981 Digital/analog reverberation unit (BX 25 ED)
1982 World’s first compact dynamic/electrostatic headphones (K 4)
1983 New “digital-ready” modular condenser microphone system providing for
capsule/preamp interface via cable up to 200 ft long (C 460 + CK 1X, CK 2 X)
1984 Stock exchange floatation of AKG Holding AG, which holds 75% of the shares
of AKG Ges.m.b.H.
1985 Founding of a US subsidiary (March 1985)
1986 Acquisition of Ursa Major -> founding of the Digital Products Division
of AKG Acoustics
Introduction of C 1000, the first condenser stage microphone with a convertible
polar pattern and alternative phantom or 9 V battery power supply
1987 Introduction of the “K 280 Parabolic” headphones
Introduction of the DSP 610, a Delta Stereo Processor for setting up
“Delta Stereophony" sound systems
1988 Introduction of the MicroMic Series
Founding of AKG Acoustics (India) Ltd.
1989 Introduction of the “CAP 340 M” Creative Audio Processor
Introduction of the DSE 7000 Digital Sound Editor
Introduction of the K 1000 headphones for binaural listening
Acquisition of Orban and dbx Professional Products
AKG Acoustics (India) Ltd. admitted to Indian stock exchange
1990 Development and manufacturing of IXT transducers for telephones
Development of a compact version of the CAP 340 M for "Audimir" space
project
Merger of SCJ and AKG Japan
AKG acquires controlling interest in three UK companies: BSS Audio Ltd.,
Turbosound Ltd., Precision Devices Ltd.
1991 20% stake in CeoTronics/Germany, 30% stake in AMEK Technology Group
PLC/UK, the holding company which owns AMEK Systems & Controls Ltd.,
and TAC Total Audio Concepts Ltd.
New product line of integrated handsets (IHA) for telephones
Founding of “AKG Communications France”
“Audimir” space project – first investigation of the basic mechanisms of
acoustic orientation under zero-gravity conditions
Introduction of the WMS 900 and WMS 100 Wireless Microphone Systems
Introduction of the new "K Series" generation of headphones
Alliance with Lectrosonics/USA for sound reinforcement products
Alliance with Direct Research/Germany
1992 AKG acquires a 51% interest in its affiliate AKG Acoustics (India) Ltd.
AKG acquires majority stake (79%) in Edge Technology Group/UK (Turbosound,
Precision Devices, BSS Audio)
Introduction of Tri-Power Series dynamic performance microphones
AKG Blue Line Series modular microphone system
C 547 boundary microphone
C 621, C 647 gooseneck microphones
Audiosphere BAP 1000 Binaural Audio Processor for Individual Virtual
Acoustics launched in Germany and Austria
Presentation of new sound reinforcement equipment
MAP Modular Audio Processor and AS 100
Introduction of TMS II Digital Telephone Measurement System
C 12 A
1962 saw the introduction of the C 12 A Nuvistor condenser micropho-
ne, an enhanced version of the C 12. The Nuvistor miniature tube tech-
nology made it possible to design even smaller high-quality large-dia-
phragm microphones. At the same time,
the distinctive shape of the C 12 A body
was the forerunner of the classic C 414:
even today the design of the C 414 is an
internationally admired and patented
three-dimensional trademark.
C 12
1953 marked the birth of another AKG legend: with the development of
the C 12, AKG introduced its first large-diaphragm condenser micro-
phone with a remote-controlled polar pattern. Initially produced in bat-
ches of 50 units a month, the C 12 quickly became a top international
product, being adopted by nearly all leading radio stations and recor-
ding studios. The first customers included the BBC in London, where the
microphone’s design and quality made a deep impression.
K 180
In 1969 AKG developed the K 180, the first
set of headphones with SCS – “Subjective
Controlled Sound”: the sound could be
varied by adjusting the speakers inside
the earphones.
AKG HISTORY

The breakthrough
At the beginning of the 1950s, the two
ambitious founders of AKG achieved a break-
through with completely revolutionary techno-
logies. They applied for patents for their
moving coil technology and the principle of the
mass loaded diaphragm. For the first time,
they were successful in extending the frequen-
cy response to the bass range. Whereas pre-
vious microphones had given a strange shrill,
hollow sound similar to that in old talking
motion pictures, AKG technology now added
warmth and volume to the sound.
In 1953 the first dynamic microphone star-
ted its conquest of world markets: the D 12
took studios, broadcasting stations, movies,
theaters, public speaking places, etc. by
storm. It was followed by two successors, and
for more than a decade set the standards for
voice miking.
The first notable successes in the field of
condenser microphones were achieved soon
afterwards. The C 12 tube microphone set new
standards in the professional sector.
AKG engineers used the CK 12 microphone
capsule for the equally successful C 12A and
the C 24, a stereo version. Even in the 21st
century, the capsule is one of the foremost
innovations from AKG. The newest version –
the C 12 VR – also won the Tec Award for the
year 1995.
The K 10 set a new milestone in the head-
phone market. This AKG product is still on the
market today, and is used at the European
Parliament, for instance.
Expansion course
Dynamic microphones for tape recorders
formed the cornerstone of AKG’s German sub-
sidiary, founded in 1955. Leading manufactu-
rers of tape recorders such as Philips, Grundig,
Uher, Loewe Opta, Nordmende, Telefunken
and others all purchased their microphones
from AKG. Since most of these customers
were located in Germany, and it was difficult
for AKG to supply them from an occupied
Austria, some of the production facilities and
the sales division were relocated, initially to
Munich.
In the early years, AKG did not have its own
sales network, using Siemens and other large
companies as distribution partners. By the end
of the 1950s, however, the company already
had distribution partners in Europe and over-
seas. Thanks to Austria’s neutrality, the com-
pany was also able to establish links with the
countries of the former East Bloc. It was only
during the 1960s that AKG also started to
build up contacts in the Far East and Latin
America.
During the years that followed, AKG concen-
trated on studio products, and opened up a
new market with portable reverb equipment.
By 1965 television had reduced the attrac-
tion of the big movie theaters so significantly
that motion picture equipment was dropped
from the production range entirely. From this
time on, AKG engineers focused on their origi-
nal strength: audio transducer technology.
Top products soon followed in all areas, like
the dynamic two-way microphone, the modu-
lar condenser microphone system (CMS) and
the K 141, which was ideally suited for both
studio use and for hifi equipment. The C 414
set yet another standard in studio recording.
At the beginning of the 1970s, pickups
were added to the consumer product line,
where AKG achieved success with a series of
top quality models until the advent of the com-
pact disc superseded the record player. AKG
subsequently withdrew from this market seg-
ment.
A new and exciting product line was found
in transistorized telephone handset capsules,
A PIONEER IN ACOUSTICS FOR OVER 50 YEARS
AKG - A LEGENDARY BRAND
4www.akg.com
Rock me Amadeus
Falco, Austria’s most successful pop star to date – was a convinced and enthusiastic AKG user
right from the beginning of his career. 1983 saw the relaunch of the legendary C 12 large-dia-
phragm tube microphone using the original 6072 tube – the “AKG Tube”.
Peter Wolf
With eight number one hits to his credit, Peter Wolf is
one of the most successful Austrian composers and pro-
ducers. Top acts he worked for include Jefferson
Starship, The Commodores, Santana, The Scorpions,
Frank Zappa, and many others.
AKG HISTORY

and these products rapidly became one of the
mainstays of the company. AKG was also quick
to introduce digital technology: the company
made its debut at the 1980 Olympic Games in
Moscow with the TDU 7000 time delay unit.
The turning point
1984 was a fateful year for AKG. The com-
pany went public on the Vienna Stock
Exchange as a “blue chip”, and performed
outstandingly for many years. At the same
time, the owners of the company started to
change, resulting in several different majority
shareholders – major banks and private finan-
ce companies – in quick succession.
This went hand in hand with the company’s
new policy of expansion. The acquisition of
other firms with complementary products was
intended to help AKG achieve its goal of beco-
ming an all-round supplier. The turning point
came with the great recession and the collap-
se of various currency parities: the leading
banks changed their strategies of maintaining
industrial holdings. At the beginning of the
1990s, AKG reported a loss for the first time
in its history. In 1993 Harman International
Inc. acquired a 76 percent stake in the AKG
Group, buying up the remaining 24 percent
the following year.
This also obliged AKG to fall back on its tra-
ditional strengths. Today microphones, head-
phones, industrial and telecommunications
products make up the company’s core busin-
ess. The company’s success has proved that
this was the right decision for AKG.
In 1996 AKG entered wireless technology,
an entirely new segment, introducing first the
WMS 300 UHF multichannel system, followed
by the WMS 800 and WMS 900 models. This
technology was entirely revolutionary at the
time, and was eagerly taken up for stationary
applications such as conference centers and
theaters. This encouraged AKG to start roun-
ding out the range in the year 1999 by deve-
loping a series of mobile UHF and VHF wire-
less systems called WMS 60 VHF, WMS 80
UHF, WMS 61 VHF, WMS 81 UHF, as well as
the IVM 1, AKG’s first in-ear monitoring
system. The company also went on to develop
wireless headphones, the youngest generation
of which is also equipped with the latest
Surround technologies.
In 2004, AKG products are available and
popular all over the world. AKG Acoustics has
become a leading manufacturer of audio pro-
ducts worldwide (more than 1,400 patents
applied for). It is with good reason that count-
less professional and amateur users around
the world rely on proverbial AKG quality.
www.akg.com 5
WMS 300
In 1996 AKG launched the WMS 300, its first UHF wireless microphone system. This UHF multichannel
system convinced the experts not only with its sound, but also its innovative modular design with inter-
changeable microphone elements and a wide selection of accessories.
CK 77
In 1995 AKG introduced the CK 77/C 577,
the world’s smallest dual-diaphragm
microphone for theater, television and
movie applications. This revolutionary
dual-diaphragm technology made the
microphone insensitive to impact noise,
whilst the microphone’s compact dimen-
sions made it virtually invisible when worn
with makeup or costumes. In combination
with WMS wireless technology, the mic ope-
ned up an almost unlimited number of
applications in any live situation.
New research center
In 2001 AKG opened a new acoustics research center with Europe’s largest anechoic chamber (18 m3)
at the company’s headquarters in Vienna. This is where AKG continuously develops new patents, and
manufactures most of its high-quality products – some of them still assembled by hand – for exporta-
tion to all parts of the world.
1993 Introduction of the “Tri-Power C Series”
Introduction of the “K Series” headphones
New AKG factory building completed
The entire factory, storage facilities, and all production departments move to the
new premises
Harman becomes new majority owner of AKG Ges.m.b.H.
AKG Holding AG is delisted from the Vienna Stock Exchange
Hendrik Homan becomes new Managing Director of AKG Vienna
1994 AKG founder Rudolf Görike dies
Harman purchases the remaining shares to make AKG a 100%-owned Harman
International company
AKG moves to new premises in Vienna-Siebenhirten
AKG Vienna assumes responsibility for Studer products in Austria
Cell manufacturing established at AKG
AKG expands its activities in the wireless market
1995 Introduction of the Performer Series, a range of affordable microphones for
Karaoke, home recording and upcoming musicians
Introduction of the CK77, the smallest dual-diaphragm capsule in the world –
big in sound, smaller than a thumbnail in size
New infrared headphones in "eargonomic" shape (K 444 IR, K 333 IR)
World's first surround sound headphones (K 290 Surround)
Introduction of IHA 90 integrated headset for computer communication
Endorsement by “Simply Red”
1996 Introduction of WMS 300 – a newly developed UHF wireless microphone system
Endorsers Simply Red on worldwide tour with AKG WMS 900
Introduction of Mini Elf and City Elf, extremely lightweight headsets
MicroMic Series II introduced
Invention of new VARIMOTION™ SYSTEM diaphragm technology
New range of high-quality headphones (K 501, K 401, K 301)
Introduction of K 205 UHF headphones
AKG nominated for European Design Award
1997 50th anniversary of AKG
Introduction of the SolidTube which makes the legendary AKG tube
technology available at an attractive price!
AKG IVM 1 In-ear Monitor System using IVA Technology.
1998 The year of the Hearo 777: IVA technology for optimum surround sound
experience
AKG WMS - multi-channel wireless microphone system
Modular Discreet Acoustics Series for Conferencing
Maximum mobility with the WLS 6060 MAX
Introduction of the CS 1 conference system
1999 Introduction of the C 4000 B the world's first dual large-diaphragm system
WMS 80, WMS 61, WMS 81 wireless microphone systems bring new sounds
for a wireless world
Hearo 999 Audiosphere for the optimum surround sound listening experience
2000 C 3000 B receives M.I.P.A. 2000 (Musikmesse International Press Award)
WMS 40: UHF system combining professional quality and exceptional cost
efficiency
Launch of C 4500 B-BC Broadcasting Condenser Microphone
2001 C 3000 B becomes reference for Roland COSM microphone modeling
HEARO 777: world's first headphones using Logic7 technology
C 451 B - new version of former C 451's
WMS 40 PT
MicroMic Series III, comprising four new models
2002 Introduction of the CS 2 Conference System
C 900 available as gold version and winner of the TEC Awards
Q 1000 Array Microphone für Mercedes
World Cup 2002 in Korea mit AKG
AKG HISTORY

The case for wireless mics
The popularity of wireless systems is gro-
wing continuously, and they are no longer
found only at open-air events, in theaters,
and conference centers. The increasing sel-
ection of small portable wireless systems is
the key to virtually unrestricted wireless free-
dom even for amateur musicians and low-
budget users, opening up a huge diversity of
applications.
The decisive factors behind the dramatic
success of wireless systems are the easy
handling and reliable, interference-free ope-
ration now offered by most of the medium-
price wireless systems available on the mar-
ket today. In practice, however, wireless
technology is often unreasonably put down
when minimal technical conditions are not
met, usually by people who do not know any
better.
The following section examines the princi-
ples of trouble-free wireless transmission and
gives an insight into what is technically pos-
sible, and how to achieve the best results.
Just like a radio set
At first it may sound simplistic to maintain
that the operation of a wireless system is
almost as simple as that of a radio set.
However, in practice closer inspection shows
that this comparison is entirely appropriate.
Everybody knows that the reception quality of
radio signals depends not only on the locati-
on of the receiver, but also on the quality of
the transmitter, i.e. whether or not you are
inside a building, and which transmission
frequency is selected (FM 100.4, for
instance). If the reception is poor, the first
thing we do is to try and change the position
of the receiver (the radio set). Then we try to
change the position of the antenna, and if
none of these remedies helps, we try to recei-
ve the desired radio station on another fre-
quency (FM 94.7, for instance). This is a per-
fectly normal procedure, and no one would
think of calling a radio set defective or unre-
liable, simply because each of us can opera-
te a radio with our eyes shut.
Since reasonably priced, high-quality wire-
less microphone systems have only been
available to the general public for a few
years, it will probably take a while for people
to become as familiar with this new techno-
logy. However, the comparison with a radio
set is particularly appropriate and helpful for
the technically uninitiated, since most peo-
ple are able to operate radio sets correctly
thanks to their intuition and experience.
Radio waves instead of cables!
With wireless technology, radio waves are
used instead of a microphone cable to trans-
mit a signal. For this purpose, we need a
transmitter that transforms the audio input
signal (voice, instrument, etc.) into a UHF or
VHF signal and broadcasts it just like a
miniature FM radio station. The receiver then
transforms this high-frequency UHF or VHF
signal back into an audio signal and ampli-
Transmitter/receiver
The situation with a transmitter and a receiver can be com-
pared to the transmission of a signal between a radio stati-
on and a radio set. When we encounter problems with recep-
tion, we will either reposition the antenna, or look for the sta-
tion on another frequency. The principles are exactly the
same when it comes to a wireless microphone system. One of
the most important rules is that you can only receive one sta-
tion at a time with a radio, never several simultaneously.
Reflection and scattering
Every wave has certain physical properties, and this also applies in the case of wireless transmission. When a wave travels from
one medium to another, part of it is reflected and another part of it absorbed. Propagation of the absorbed part of the wave in
the denser medium is considerably reduced, whilst the reflected part is returned at the same angle as the angle of incidence
(diagram on left).
When a wave meets an irregular surface, it is not reflected uniformly and linearly, but is scattered in several partial waves, each
deflected by a differing amount (diagram on right). The energy level of the wave naturally declines every time it is reflected,
absorbed or scattered.
Shadowing
When a wave passes close to an obstacle, it is deflected slight-
ly from its linear path. Thus a number of small obstacles in a
room, such as wire screens, etc., can result in shadowing los-
ses although visually they appear transparent.
HOW RADIO SIGNALS ARE TRANSMITTED
HOW WIRELESS TECHNOLOGY WORKS
6www.akg.com
AKG WMS BASICS

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Signal propagation
As in a game of billiards, it is often impossible to reach a goal
via a direct path. In the diagram on the left the red ball repre-
sents the receiver, the while ball the signal, and the black ball
an obstacle between the two. However, in practice we are not
dealing with a single ball, but with very many simultaneously.
Thus there is a comparatively high probability that at least one
of the balls will reach its goal.
1. The signal hits the obstacle directly and fails to reach its
goal.
2. The signal reaches its goal after being reflected off the wall.
3. If two signals reach their goal simultaneously, they cancel
each other out in a situation referred to as dropout.
4. In spite of being reflected, the signal fails to reach its goal,
and continues to be propagated until its energy is expen-
ded.
fies it as necessary. An FM radio set – which
everyone is familiar with – works on exactly
the same principle.
Now that we have seen that a wireless micro-
phone system functions just like an FM radio
station on a narrow bandwidth, we can also
see that it is subject to exactly the same phy-
sical laws that govern the propagation of
radio waves. The challenge here is to find a
technical solution to the typical phenomena
of wave propagation, such as cancellation,
heterodyning, and absorption. Other factors
such as RF interference, electrical and elec-
tromagnetic fields, and intermodulation are
also severely disruptive, and have a negative
impact on the transmission quality of a wire-
less installation, significantly impairing the
quality of the radio link and the audio signal.
But more about that later!
It is particularly important to choose the right
antenna and set up the antenna and receiver
correctly if we wish to avoid loss of quality.
The rule of thumb is that the best radio
transmission path is always the line of sight.
Antennas and receivers should therefore
never be hidden behind walls or other objec-
ts – it is vital to have a free line of sight bet-
ween them! Problems with wireless systems
during club gigs are frequently caused by
incorrectly positioned antennas, although
everything functioned perfectly during the
sound check. In this case the audience forms
an imaginary “wall” between the transmitter
and the receiver, severely attenuating the
radio signal. The best thing you can do is
position the antenna high enough above the
audience to avoid such a situation.
Do not place the antenna behind gratings,
metal surfaces, or behind curtains if you can,
as the signal will be unable to penetrate such
obstacles. Even neon lights, dimmers,
lighting systems, electronic equipment with
strong RF radiation, like computers and stage
effects, power switching equipment, keybo-
ards, etc. are potential sources of interferen-
ce. They produce high-frequency harmonics,
and are therefore totally unsuitable for use
near the antennas of wireless systems. The
minimum distance between walls and anten-
nas should not be less than 3 feet, and the
recommended minimum distance between
transmitter and receiver is 10 feet.
You can get even better results by using
diversity systems, carefully selecting the car-
rier frequency band (UHF or VHF), and pla-
cing the antenna(s) carefully to prevent any
dead spots. If none of the above methods
alone improves the situation, try them in dif-
ferent combinations. If this still does not
help, you should secretly check that the
receiver is connected to power, and that fresh
batteries have been inserted in the transmit-
ter! But seriously, even professionals have
made this mistake in the commotion of set-
ting up the equipment for a gig!
Positioning the receiver
One of the most common mistakes in practice is failing to take the audience into account when positioning the receiver. The basic rule of thumb is: always maintain a line of sight between the
transmitter and the receiver. In order to prevent the signal from being absorbed by the audience, always place the receiver as high as possible and in the vicinity of the transmitter – ideally
on the stage itself.
AKG WMS BASICS

Wireless transmission technology is based on
the physical principles governing the propa-
gation of electromagnetic waves. Radio, tele-
vision, mobile telephone communications, mi-
crowaves, and light are all based on electro-
magnetic waves with different wavelengths.
Short waves have completely different cha-
racteristics, and are propagated as high-fre-
quency signals in the form of radio waves or
X-rays, for instance, traveling incredible
distances through the universe and still
detectable after millions of years.
Speech and other sound signals, on the other
hand, are not electromagnetic waves, and
require a high-frequency carrier signal for
wireless transmission: it is this carrier signal
that serves to transport the audio signal
through the air. The process that does the
trick is called modulation: this is similar to
the audio signal getting into a taxi in a scien-
ce-fiction movie (climbing into a radio-fre-
quency signal), because the physical laws
that now come into effect are similar to the
highway code of the future! This metaphori-
cal example is not entirely analogous to the
physical reality, but it may give a clearer pic-
ture.
What happens to our audio signal once it has
entered our metaphorical taxi in order to tra-
vel from the transmitter to the receiver? First
it has to tell the driver its destination, for
example: “Please take me the fastest way
from transmitter to receiver.” Since he has
been asked to take the fastest route, the taxi
driver will try to select this route. However,
the thing is that we are not alone on our jour-
ney, but have to share the roads with a num-
ber of other (wireless) road users: in this
situation the following rules apply:
Rule no. 1:
The stronger your radio signal is, the better
chance it has of reaching its destination. In
our metaphorical example, TV stations do not
travel in radio-wave taxis in one lane, but in
gigantic trucks occupying several lanes at
once. The only solution here is to avoid them
by selecting another frequency band, in our
example by taking another road so as not to
be run over by them!
Rule no. 2:
Keep your distance and stay in your lane! Our
taxi needs a road lane on which it can travel,
and must keep its distance from vehicles in
the adjacent lanes so as to avoid a collision,
which we refer to in technical terms as radio
interference. Unfortunately, however, we are
also obliged to share our lane with signal
waves from mobile telephones, television
sets, microwave ovens and radio sets, and are
permanently faced with congestion and traf-
fic jams. These other signal waves continual-
ly come dangerously close to our taxi, and we
are continually in danger of colliding with
other road users: it is therefore essential that
we keep our distance!
Rule no. 3:
The higher the frequency, the more “lanes”
there are available, and the risk of various
radio signals colliding with one another is
correspondingly lower. This is why all
WMS 40 systems work in the short-wave UHF
range, which ensures extremely reliable
transmission and optimal signal quality.
AKG has specified various radio frequencies
for its WMS 40 wireless systems in order to
ensure secure and reliable transmission in
the UHF range, normally enabling four
systems to be operated simultaneously. This
means that we are able, as it were, to send
our audio signals from transmitter to receiver
using very fast taxis on four safe road lanes.
This is particularly important when transmit-
ting speech and music in order to avoid
unwanted signal dropouts (see illustrations
on facing page and also the illustration of
signal characteristics on page 7). The maxi-
mum number of channels that can be opera-
ted simultaneously varies depending on
national licensing regulations.
The licensing regulations issued by the rele-
vant regulatory authorities for telecommuni-
cations systems also vary from country to
country. Your local AKG supplier will be able
to tell you whether you require a license to
operate a WMS 40 wireless system in your
country.
8www.akg.com
Wavelength
The properties of a wave depend primary on its wavelength. Wavelength is the term used to refer to the distance between points at which the wave has the same phase in two consecutive
cycles. The radio waves of wireless microphone systems, and also television and radio sets, mobile telephones and microwave ovens, have a wavelength of about a meter. The wavelength of
visible light varies between 770 and 400 nm (1 nm = 1 thousandth of a meter), whilst X-rays, gamma rays, and cosmic radiation have even shorter wavelengths.
AKG WMS BASICS
HOW RADIO SIGNALS ARE TRANSMITTED
HOW WIRELESS TECHNOLOGY WORKS

Interference
Overlapping (interference) occurs when the bandwidths of
adjacent signals are too wide, or the carrier frequencies are
too close together. Parts of the signals transmitted lying in
this range are no longer clearly recognized by the receiver,
resulting in noise or dropouts. For this reason it is not pos-
sible for two or more systems to work on the same frequen-
cy. Even if the frequencies are different, one must always
ensure that there is sufficient separation between the fre-
quencies used.
Color coded for easy identification
It is easy to match up transmitters and receivers thanks to
their color coding system. At the same time, the colors also
tell you the carrier frequency used for the radio link.
Transmitters and receivers using the same carrier frequency
are coded with the same color. The color code clips on the
HT 40, SO 40, MP 40, and GB 40 transmitters are removable,
and can be replaced by the black clip provided.
Bandwidth
Every frequency-modulated carrier signal does not oscillate
entirely within the frequency allocated to it, but also occu-
pies frequencies in the adjoining range. This range is known
as “bandwidth”. The wider the available bandwidth is, the
better the transmission quality. Ideally, different carrier sig-
nals should therefore be far enough apart to prevent their
bandwidths from overlapping.
Example of AKG WMS 40 carrier frequencies
AKG has selected fourteen different frequencies as carrier
frequencies for wireless transmission by WMS 40 wireless
systems. There is sufficient separation between them to
ensure trouble-free operation and optimal signal quality. A
maximum of four WMS 40 systems can be operated at any
one time, and care must be taken to ensure that none of the
frequencies are used twice! If more than four radio links are
required simultaneously, AKG offers a series of wireless
systems that make it possible to use a higher number of
channels at once. Please refer to pp. 30 for detailed infor-
mation. The maximum permissible number of channels may
vary depending on national frequency plans.
Frequency Modulation (FM)
Transforming an audio signal into a radio-frequency one and
back again is achieved by means of frequency modulation
(FM). This technology has also been used for decades in UHF
radio to ensure reliable transmission and high signal quali-
ty. This involves imposing an audio signal on a radio-fre-
quency (RF) sine-wave carrier that now begins to oscillate in
time with the audio signal. Variations in the level of the
audio signal (changes in volume) produce frequency chan-
ges in the RF carrier signal (transmission frequency).
Therefore, this technique is known as “frequency modulation”.
www.akg.com 9
➜
➜
➜
➜➜
➜
➜
AKG WMS BASICS

Handheld microphone for lead and
backing vocals
•
Simple plug & play system
• Time-tested AKG D 880
M
microphone element
• Over 35 hours of battery-powered operation
Page 12
MODULAR SOLUTIONS TO MEET INDIVIDUAL REQUIREMENTS
THE WMS 40 MODULAR SYSTEM
Lead and backing vocalsTM 40
10 www.akg.com
The requirements of wireless systems vary
from one user to another. This calls for indi-
vidual solutions, which is why AKG has crea-
ted the WMS 40 series as a modular system
that offers a wide range of solutions depen-
ding on the user’s preferences and chosen
field of application. Up to four WMS 40
systems can be operated simultaneously: if
you need to use more than four radio links at
once, you should consider choosing a
WMS 400 or WMS 4000 system instead. See
pp. 30 for further details. AKG’s WMS 40
systems are designed for the future. You can
also use any WMS 40 system with other AKG
WMS wireless systems if required. However,
if you do, we recommend you visit our websi-
te at to check for suitable frequencies before
you make your purchase or use the system.
For this purpose, AKG offers a service enab-
ling you to input the carrier frequencies of
your existing WMS systems. The available
carrier frequencies of other AKG WMS
systems will then be calculated for you auto-
matically. The maximum permissible number
of channels may vary depending on national
frequency plans.
The SO 40 snapon transmitter is the best
value WMS system for a singer who already
possesses a microphone. However, AKG
offers a wide range of professional solutions
for a whole spectrum of other applications
such as vocals, aerobics, presentations, and
the wireless transmission of instruments. In
the final analysis, the decisive factors boil
down to your individual requirements and the
budget you have at your disposal!
The choice is yours…
HT 40
AKG WMS OVERVIEW
PT 40
C 420 L
Snapon for easy transition from cable
to wireless
•
Suitable for any dynamic microphone
• Condenser microphone with internal battery
supply
• XLR connector for easy connection
• Optional quick charging station
• Integrated charging contacts
Page 16 SO 40 e.g.
AKG D 880MSR 40
TM 40 e.g.
AKG D 880M
SR 40 diversity
SR 40 diversity
SR 40
Head-worn microphone for lead and
backing vocals
•
Absolute mobility
• Choice of C 444 L or C 420 L head-worn
microphones
• Over 35 hours of battery-powered operation
Page 14
High Quality Wireless Transmitter Module
• The TM 40 connects to Emotion Tripower
Series microphones D 3700M, D 880Mand C 900M
• Lowest operating cost in its class
• Input gain control for optimum matching to
microphone output level
• ON/MUTE/OFF switch and battery status
indicator for easy setup
Page 18

www.akg.com 11
PresentersInstruments
Guitar, bass
and keyboards
oder
Aerobics
AKG WMS OVERVIEW
The MP 40 micropen for presenters
• Maximum flexibility of use as handheld,
clip-on, or pocket mic
• Superior-quality C 407 capsule
• Optional quick charging station
Page 20 MP 40 PR 40
Handheld microphone for presenters
• Simple plug & play system
• Time-tested AKG D 880Mmicrophone element
• Over 35 hours of battery-powered operation
Page 22 HT 40 SR 40
C 444 L
C 417 L
SR 40
PT 40
Clip-on or head-worn microphone
for presenters
• Absolute freedom of movement
• Choice of C 444 L head-worn or
unobtrusive C 417 clip-on microphone
• Over 35 hours of battery-powered operation
Page 22
C 444 L PR 40
PT 40
Head-worn microphone for extreme
activities like aerobics and sports
•
Absolute freedom of movement
• C 444 L head-worn microphone specially
protected against moisture and perspiration
• Over 35 hours of battery-powered operation
Page 24
PT 40
MicroMic
SR 40 diversity
Wireless systems for portable
instruments
• Absolute mobility
• Choice of a variety of miniature microphones
specifically designed for instrument use
• Over 35 hours of battery-powered operation
Page 26
PR 40
GB 40
The GB 40 guitarbug for guitar,
bass and keyboards
• Flexjack swiveling jack plug connects to all
types of electric guitars and basses
• Simple plug & play system
• Optional quick charging station
Page 28

The HT 40 handheld transmitter is an excel-
lent choice for both handheld and stand-
mounted use. Handheld microphones are also
suited for applications where more than one
person will talk into the microphone, such as
talk shows or interviews with people in the
audience.
The design specification for the WMS 40
Series lists the best possible audio quality as
the number one priority. The result explains
the success of the WMS 40 system. This UHF
wireless microphone system has been opti-
mized for use in smaller venues such as clubs,
rehearsal rooms, or local community centers,
is easy to use, and provides outstanding
price/performance.
The heart of the HT 40 handheld transmitter
is the AKG D 880Mmicrophone element that
delivers both an excellent sound and very good
intelligibility. This microphone element uses
the same transducer as the hot-selling, proven
AKG D 880Mhardwire microphone. Made at
the AKG factory in Vienna, Austria, each trans-
ducer must pass extremely stringent quality
tests before being approved for shipping. This
is another reason why both professional and
amateur vocalists appreciate this transducer.
It guarantees excellent results from the start
and is almost indestructible.
With its compact, rack-mountable receiver,
the AKG WMS 40 is an easy-to-use, conveni-
ent wireless system, and once you tried it you
won't want to do without it anymore.
Excellent response
The HT 40 handheld transmitter uses the
proven AKG D 880
M
microphone element.
This dynamic transducer has been specifi-
cally designed for lead and backing vocals
and helps even less experienced vocalists
to make themselves heard. An integrated
wind and pop screen effectively reduces
breath and pop noise as well as sibilance.
It is easy to remove the windscreen from
the front grill for cleaning.
HANDHELD MICS FOR LEAD AND BACKING VOCALS
AKG WMS 40 UHF FOR VOCALS
Massive front grill
An extremely rugged spring steel wire-mesh cap optimally
protects the transducer capsule beneath it from damage in
tough night-after-night usage on stage. The proven AKG
D 880 microphone element easily survives a drop from
approx. 3 1/2 feet (1 m) to a hard stone floor. It has been
designed to take the kind of abuse usually encountered on
tour.
ON/MUTE/OFF switch
The absolutely noiseless ON/MUTE/
OFF switch with its knurled lever is
recessed in the body to prevent
unintentional actuation and en-
sure maximum operational safety.
Replaceable color code clip
The color code clip indicates the carrier
frequency of the transmitter, and you can
replace the colored clip with an inconspi-
cuous black replacement clip if and when
the need arises.
Integrated antenna
The antenna is hidden inside the rugged
transmitter body for optimum protection
from damage.
Battery status LED
With a minimum battery life of 35 hours,
the HT 40 gives you more hours of fun
per dollar than most of its competitors.
And if the battery status LED illuminates
after all, don’t panic: you still got
50 minutes before the batteries are
dead so you can easily steal away for a
minute to replace them.
Rack mounting
Both the SR 40 and the SR 40 diversity can be used free-
standing or rack mounted. An optional rack mounting kit
allows you to install the receiver quickly and easily in any
19" rack. The half-rack, 1 U case lets you mount the recei-
vers for six channels in just 3 U of rack space.
12 www.akg.com
HT 40 Handheld transmitter
AKG WMS UHF VOCALS

Volume
Matches the output level of the receiver to the
input gain of the mixer. (For details refer to
page 27)
Frequency color code platelet
Receivers using the same frequen-
cy are marked with the same color
code.
RF LED
Illuminates to indicate that RF signal is being
received. If the RF signal fails or the squelch
comes on, the MUTE LED will be lit.
On/off switch
with status LED.
Antenna
The swiveling antenna is mounted on the
front panel, allowing the receiver to be
rack mounted.
Case
The side panel supports are removable for
mounting the receiver in a 19" rack.
Angle of incidence
To get a well-balanced, natural sound, sing to one side of the
microphone or above and across the microphone’s top (left).
If you sing directly into the microphone, it will not only pick
up excessive breath noise but also overemphasize sibilants
(right).
Holding the transmitter
Be sure never to cover the lower half of the wire-mesh cap
with your hand. If you do, the microphone element's polar
pattern will change from cardioid to omnidirectional. In a
concert hall, this change in the pickup pattern will signi-
ficantly lower the usable gain before feedback. Also, do not
grasp the transmitter body at the lower end, where your
hand would cover the integrated antenna and weaken the
radio signal.
Working distance and proximity effect
Basically, your voice will sound the bigger and mellower, the
closer you hold the microphone to your lips. Moving away
from the microphone will produce a more reverberant, more
distant sound as the microphone will pick more of the room’s
reverberation. Proximity effect is a more or less dramatic
boost of low frequencies that occurs when you sing into the
microphone from less than 2 inches. It gives more "body" to
your voice and a sexy, bass-heavy sound.
Feedback
To increase usable gain before feedback, the microphone
on the HT 40 has a supercardioid polar pattern. This means
the microphone is most sensitive to sounds arriving from in
front of it (your voice) while hardly responding to sounds
arriving from the sides or rear (from monitor speakers for
instance). To maximize gain before feedback, never point
any microphone directly at a speaker. The safest place for
a microphone is usually behind the FOH speakers.
www.akg.com 13
Microphone cleaning and maintenance
Microphones, like any other instrument, need regular clea-
ning to maintain clarity and intelligibility. As a microphone
is being used, its foam pop screen and front grill collect dirt
particles that may ultimately clog the acoustically transpa-
rent foam cells. Just unscrew the front grill and remove the
internal windscreen. Soak the windscreen in sudsy water for
a night, then allow it to dry completely. Clean the front grill
with isopropyl alcohol.
Alternative receivers
You can also use the HT 40 with the SR 40 diver-
sity receiver or the PR 40 portable receiver.
Squelch threshold control
(on rear panel). SR 40 Receiver
AKG WMS UHF VOCALS

HEAD-WORN MICS FOR LEAD AND BACKING VOCALS
AKG WMS 40 UHF FOR VOCALS
Mini XLR connector
A locking 3-pin mini XLR connector pro-
vides a reliable connection to a head-
worn microphone from AKG.
ON/MUTE/OFF switch
Setting the switch to the "MUTE"
position mutes the audio signal,
while the transmitter continues
radiating the RF carrier frequency.
This prevents the receiver from
being disturbed by other transmit-
ters while the microphone is “off
the air”.
Flexible antenna
To maintain perfect transmission, the
antenna should be visible from the recei-
ver location at all times. So make sure
never to cover the antenna with clothes or
other elements of the costume.
Battery status LED
With a minimum battery life of 35 hours, the PT 40
gives you more hours of fun per dollar than most of its
competitors. And if the battery status LED illuminates
after all, don’t panic: you still got 50 minutes before
the batteries are dead so you can easily steal away for
a minute to replace them.
Rear panel and battery compartment
Belt clip for fixing the transmitter to a belt.
Frequency and color code label for easy frequency identification
in a multichannel system.
MIC/LINE selector: Sets the audio section input either to MIC or
LINE level.
GAIN: Fine adjusts the sensitivity of the transmitter’s audio sec-
tion to the output level of the connected microphone or
instrument.
Head-worn microphones are becoming
increasingly popular with vocalists who also
play an instrument, or performers needing
absolute mobility, particularly those who do
not only sing but also dance on stage. The
C 420 L and C 444 L from AKG are head-
worn condenser microphones that provide a
perfect vocal sound, wide dynamic range,
and good intelligibility.
Sharing the outstanding, proverbial quality
AKG transducers are famous for, these two
microphones deliver excellent sound.
Backed by more than fifty years of experi-
ence, AKG R&D designed microphone trans-
ducers that are small, inconspicuous, extre-
mely light, and do not obstruct the user's
field of vision. The transducers are made by
AKG in Austria, Europe.
The C 420 L and C 444 L are cardioid
microphones that focus their sensitivity at
the user's mouth and reduce unwanted off-
axis noise to a minimum. The AKG WMS 40
is a UHF wireless system with an outstan-
ding price/performance ratio. It has been
designed to bring uncompromising audio to
smaller venues such as clubs, rehearsal
rooms, or local community centers. It
makes professional UHF technology acces-
sible to musicians on a budget and is an
ideal choice for lead vocalists as well as
singing keyboardists, drummers, guitarists,
or dancers. The WMS 40 combines ease of
use with a simply fabulous sound!
14 www.akg.com
PT 40 Portable transmitter
AKG WMS UHF VOCALS

C 420L
A fully adjustable behind-the-neck steel headband with
swiveling temple pieces provides a secure yet gentle fit.
The cable is connected at the back of the head so it won't
get into the user's way during the performance.
The microphone arm places the mic in front of the user's
mouth, a position suited for professional vocalists who
know how to sing and breathe to avoid causing breath and
pop noise.
www.akg.com 15
Volume
Matches the output level of the receiver to the
input gain of the mixer. (For details refer to
page 27).
AF LEDs
The green AF LED indicates the input level to the audio
section is within the optimum range. If the audio input
level is too high, the PEAK LED will come on.
Diversity LEDs
Indicate which of the
two receiving anten-
nas is currently active.
Frequency color code platelet
Receivers using the same frequency are mar-
ked with the same color code.
RF LED
Illuminates to indicate that RF signal is being
received. If the RF signal fails or the squelch
comes on, the MUTE LED will be lit.
ON/OFF switch
with status LED.
Antennas
The swiveling antennas are mounted on
the front panel, allowing the receiver to be
rack mounted.
Case
The 1 U half-rack case is easy
to mount in a rack and allows
you to install two receivers in a
single slot.
Alternative receivers
You can also use the PT 40 with the SR 40 stationary receiver or the PR 40 portable receiver.
SR 40 diversity Receiver
Rack mounting
Both the SR 40 and the SR 40 diversity can be used free-
standing or rack mounted. An optional rack mounting kit
allows you to install the receiver quickly and easily in any
19" rack. The half-rack, 1 U case lets you mount the recei-
vers for six channels in just 3 U of rack space.
AKG WMS UHF VOCALS

SO 40 SNAPON TRANSMITTER CONVERTS HARDWIRE MICS TO WIRELESS
AKG WMS 40 UHF FOR VOCALS
Color code
Transmitters and receivers tuned to the same carri-
er frequency are marked with the same color. Input gain control
Matches the transmitter audio input sen-
sitivity to the microphone's output level.
Battery status LED
Battery life is approx. eight hours for an AAA size 1.5 V dry battery and
approx. six hours for a rechargeable battery. When the status LED is
lit red constantly the battery will be dead in about 50 minutes. The
maximum charging time for a rechargeable battery is one hour.
XLR connector
3-pin female XLR connector for direct
connection to a dynamic microphone with a
3-pin male XLR connector.
Antenna
Rugged antenna integrated in the
transmitter body.
Release button
Unlocks the XLR connector.
ON/MUTE/OFF switch
Setting the switch to the “MUTE” position mutes the audio sig-
nal, while the transmitter continues radiating the RF carrier
frequency. This prevents the receiver from being disturbed by
other transmitters while the microphone is “off the air”.
Battery compartment
The transmitter can be powered from a dry
or rechargeable battery. The color of the
battery compartment cover indicates the
carrier frequency of the transmitter, and you
can replace the colored cover with a black
replacement cover.
Kind to your budget and the environment
The optional CU 40 charger provides a convenient way of
charging the battery inside the transmitter via the charging
contacts on the transmitter bottom panel. You don't even
have to remove the battery for charging! Unlike conventional
chargers, the CU 40 checks whether the battery inside the
transmitter is a dry or rechargeable type and switches off
automatically if it detects a dry battery. A quick charging
function makes sure the batteries inside any AKG Microtool
will be fully charged within one hour.
16 www.akg.com
SO 40 snapon transmitter
Does this sound familiar? You've been using
your favorite hardwire dynamic microphone
for gigs and rehearsals for years and one
night it turns out that for this particular gig it
would be very convenient to have the same
microphone with a radio link instead of the
cable. The radio link would have to be small,
light, and affordable, because you travel a lot
and would rather not spend a lot of money on
a full-blown wireless system that you will only
use occasionally.
It was exactly for this application that AKG
designed the Microtools Series SO 40 snapon
transmitter that was enthusiastically wel-
comed by the audio community when it was
launched and has been appreciated by many
users ever since.
Knowing that the most successful products
are usually surprisingly simple, the designers
at AKG did their homework with painstaking
care and finally came up with the SO 40
snapon transmitter, a miniature transmitter
designed specifically for direct connection to
a microphone. The SO 40 snapon transmitter
has a 3-pin XLR connector that allows you to
connect the transmitter directly to any dyna-
mic microphone (e.g., an AKG D 880) or a
condenser microphone with an internal
power supply (e.g., the AKG C 1000 S). The
transmitter can be powered from a dry or
rechargeable battery. A suitable charger is
available from AKG.
Converting a hardwire microphone to wireless
has never been so easy and affordable be-
fore. Even if you use several hardwire micro-
phones from various manufacturers for
various applications, you can now convert all
these microphones to wireless easily and
without having to buy several different wire-
less systems. In short, the SO 40 snapon
transmitter gives you incredible wireless fle-
xibility at very moderate cost.
AKG WMS UHF VOCALS

Volume
Matches the output level of the receiver to the
input gain of the mixer. (For details refer to
page 27).
Frequency color code platelet
Receivers using the same frequen-
cy are marked with the same color
code.
RF LED
Illuminates to indicate that RF signal is being
received. If the RF signal fails or the squelch
comes on, the MUTE LED will be lit.
ON/OFF switch
with status LED.
Antenna
The swiveling antenna is mounted on the
front panel, allowing the receiver to be
rack mounted.
Case
The side panel supports are removable for
mounting the receiver in a 19" rack.
XLR connector
Plug it in. That's all you need to do to convert any hardwire dynamic mic to wireless.
Obviously, you can use the SO 40 to add a radio link to any other audio source with an XLR output as well.
The XLR connector on the SO 40 is wired for pin 2 hot (international standard).
12
3
www.akg.com 17
Setting the squelch threshold
The job of a s squelch circuit is to reduce audible noise. It
eliminates noise during pauses in the audio signal by
muting the receiver every time the audio level drops below a
defined threshold. The SQUELCH control on the receiver sets
this threshold. Use the SQUELCH control with care! If the
squelch threshold is too high, the squelch will not only cut
out noise but mute quiet audio signals as well because the
squelch responds to the detected voltage and cannot distin-
guish between wanted signal and noise. Besides that, a too
high squelch treshold also decreases the usable range.
Alternative receivers
You can also use the SO 40 with the SR 40 diver-
sity receiver or the PR 40 portable receiver.
SR 40 Receiver
AKG WMS UHF VOCALS
SO 40 Input wiring diagram
XLR connector
(pin 2 hot)

Sooner or later in the life of every singer, the
time comes when you need to buy a rugged
stage microphone with that fabulous sound.
But that’s when you find yourself in a dilem-
ma: do you need a hardwire or a wireless
mic? A hardwire model is perfectly adequate
for the rehearsal room, where it is often
impossible to use a radio system due to the
small distances involved. On the other hand,
the benefits of a wireless microphone during
a live performance are obvious: no endlessly
long cables, and complete freedom of move-
ment. But this is hardly enough to make you
want to buy two microphones.
This problem is now a thing of the past
thanks to the revolutionary TM 40 transmit-
ter module. Depending on the situation, with
an easy adjustment you can use this micro-
phone with or without a cable.
It goes without saying that you can always
opt for the hardwire version to begin with if
your budget is limited. You can subsequently
upgrade to the wireless version at any time
without being annoyed about owning a hard-
wire mic you no longer need.
The TM 40 transmitter module is based on
the same technology as AKG’s extremely suc-
cessful WMS 40 range, which offers a genui-
ne plug & play system for up to six channels.
This ensures problem-free operation of all
optional accessories – from receiver to char-
ger – with your TM 40. A built-in on/mute/off
switch, clearly visible status LED, and input
gain control ensure unrivaled ease of use.
What microphone you will ultimately choose
depends only on your personal preference as
a performer: dynamic or condenser, cardioid
or supercardioid – every possible combina-
tion is available.
THE TM 40 - MODULAR SYSTEM FOR SOPHISTICATED STAGE APPLICATIONS
AKG WMS 40 UHF FOR VOCALS
18 www.akg.com
Status LED
Allows you to check the status of the
battery inside your transmitter. The
TM 40 will operate for about 8 hours off
a 1.5 V AAA size dry battery, and about
6 hours off a rechargeable battery.
When the status LED lights up red con-
tinuously, the battery will last about
another 50 minutes: recharging takes
an hour at most.
On/mute/off switch
With the mute function selected, only
the audio signal is muted: the supply
voltage and RF carrier frequency
remain switched on. This prevents
other transmitters from interfering
with the receiver although the micro-
phone is “switched off”.
Input gain control
Allows you to adjust the sensitivity of the
audio input on the TM 40.
Battery compartment
You can operate the microphone with either
dry or rechargeable batteries. Integrated
charging contacts in the bottom of the micro-
phone allow you to charge the battery without
removing it.
Battery charging made easy
Use the optional CU 40 charger to recharge the battery in the
battery compartment via the integrated contacts in the bottom
of the transmitter body. The battery is recharged within one
hour and can then be used for up to 6 hours. Battery charging
simply couldn’t be easier, faster, or more ecological!
TM 40 Transmitter module
AKG WMS UHF VOCALS