AKG Acoustics WMS 4000 User Manual
WMS 40 PRO
WMS 400
Wireless
Microphone
Systems
Everything you've always wanted to know
about AKG WIRELESS TECHNOLOGY.
WMS 4000
Believe In Your Passion
AKG HISTORY
AKG - A LEGENDARY BRAND
A PIONEER IN ACOUSTICS FOR OVER 50 YEARS
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 theater equipment. And so it was that Rudolf Görike
and Ernst Pless conceived a new idea: “Let us
go into business together.” This was the beginning 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 bicycle 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 telephones, pillow loudspeakers, and many other
appliances that seem curious to us today. The
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 produced 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 diaphragm of molded granulate, since foils were not yet available.
At the time AKG had only one winding machine and one gluing
machine.
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 technologies 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.
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!
The logo
The first AKG logo with three overlapping rings (symbolizing 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 modifications, this logo has remained in use to this day, and is the
guarantee of AKG’s legendary quality the world over.
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AKG HISTORY
C 12
1953 marked the birth of another AKG legend: with the development of
the C 12, AKG introduced its first large-diaphragm condenser microphone with a remote-controlled polar pattern. Initially produced in batches of 50 units a month, the C 12 quickly became a top international
product, being adopted by nearly all leading radio stations and recording studios. The first customers included the BBC in London, where the
microphone’s design and quality made a deep impression.
C 12 A
1962 saw the introduction of the C 12 A Nuvistor condenser microphone, an enhanced version of the C 12. The Nuvistor miniature tube technology made it possible to design even smaller high-quality large-diaphragm 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.
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.
The early products
In 1945 the company began supplying
technical equipment such as movie projectors and loudspeakers to Vienna movie
theaters. The PC 2535 G horn-loaded theater loudspeaker with a cardboard diaphragm, for instance, was manufactured
in a living room.
The company name
The founders considered calling their company “Phonophot”, but because of its similarity with another name, they opted for
“Akustische- und Kino-Geräte“, or AKG for
short. Acoustic equipment became more
and more predominant, and in 1965 theater 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
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AKG HISTORY
AKG - A LEGENDARY BRAND
A PIONEER IN ACOUSTICS FOR OVER 50 YEARS
The breakthrough
At the beginning of the 1950s, the two
ambitious founders of AKG achieved a breakthrough with completely revolutionary technologies. 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 frequency response to the bass range. Whereas previous 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 started 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 headphone 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 subsidiary, founded in 1955. Leading manufacturers 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 overseas. Thanks to Austria’s neutrality, the company 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 concentrated on studio products, and opened up a
new market with portable reverb equipment.
By 1965 television had reduced the attraction 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 original strength: audio transducer technology.
Top products soon followed in all areas, like
the dynamic two-way microphone, the modular 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 compact disc superseded the record player. AKG
subsequently withdrew from this market segment.
A new and exciting product line was found
in transistorized telephone handset capsules,
Peter Wolf
With eight number one hits to his credit, Peter Wolf is
one of the most successful Austrian composers and producers. Top acts he worked for include Jefferson
Starship, The Commodores, Santana, The Scorpions,
Frank Zappa, and many others.
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-diaphragm tube microphone using the original 6072 tube – the “AKG Tube”.
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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.
came with the great recession and the collapse 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
The turning point
1984 was a fateful year for AKG. The company 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 finance 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 becoming an all-round supplier. The turning point
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 interchangeable microphone elements and a wide selection of accessories.
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
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 traditional strengths. Today microphones, headphones, industrial and telecommunications
products make up the company’s core business. 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
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 dimensions made it virtually invisible when worn
with makeup or costumes. In combination
with WMS wireless technology, the mic opened up an almost unlimited number of
applications in any live situation.
time, and was eagerly taken up for stationary
applications such as conference centers and
theaters. This encouraged AKG to start rounding out the range in the year 1999 by developing a series of mobile UHF and VHF wireless 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 products worldwide (more than 1,400 patents
applied for). It is with good reason that countless professional and amateur users around
the world rely on proverbial AKG quality.
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
2003 Another “world’s first”: Emotion/TriPower Series TM 40 module enables a quick
change from wired to wirless within the same microphone
High-End WMS 4000 – the ultimate wireless microphone system.
AKG launches headtracking system for LISTEN project (Kunstmuseum Bonn,
Germany)
Vienna Festival equipped with AKG WMS and in-ear system IVM-1
2004 C 414 X-Series (C 414 B-XLS; C 414 B-XL II), honoured with the Cool Stuff
Award 2004 (Radio World International) shortly after introduction
WMS 400 high-speed multichannel system
World’s first mobile wireless headphones Merlin 232
AKG is part of HiQnet with WMS 4000/HUB 4000
2005 CCS Series Musician Microphones
K 28 NC Noise Reduction headphones
Headsets HSD 271, HSD 171, HSC 271, HSC 171
WMS 40 PRO Series
M.I.P.A. Awards for WMS 4000 and C 414 B-XL II
TEC Award 2005 for C 414 B-X Series
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AKG WMS BASICS
HOW WIRELESS TECHNOLOGY WORKS
HOW RADIO SIGNALS ARE TRANSMITTED
The case for wireless mics
The popularity of wireless systems is growing continuously, and they are no longer
found only at open-air events, in theaters,
and conference centers. The increasing selection of small portable wireless systems is
the key to virtually unrestricted wireless freedom even for amateur musicians and lowbudget 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 operation now offered by most of the mediumprice wireless systems available on the market 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 principles of trouble-free wireless transmission and
gives an insight into what is technically possible, 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 location 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 receive the desired radio station on another frequency (FM 94.7, for instance). This is a perfectly normal procedure, and no one would
think of calling a radio set defective or unre-
liable, simply because each of us can operate a radio with our eyes shut.
Since reasonably priced, high-quality wireless 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 technology. However, the comparison with a radio
set is particularly appropriate and helpful for
the technically uninitiated, since most people 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 transmit 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-
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.
Transmitter/receiver
The situation with a transmitter and a receiver can be compared to the transmission of a signal between a radio station and a radio set. When we encounter problems with reception, we will either reposition the antenna, or look for the station 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 station at a time with a radio, never several simultaneously.
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Shadowing
When a wave passes close to an obstacle, it is deflected slightly from its linear path. Thus a number of small obstacles in a
room, such as wire screens, etc., can result in shadowing losses although visually they appear transparent.
AKG WMS BASICS
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 represents 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 expended.
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 microphone system functions just like an FM radio
station on a narrow bandwidth, we can also
see that it is subject to exactly the same physical 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 electromagnetic fields, and intermodulation are
also severely disruptive, and have a negative
impact on the transmission quality of a wireless 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 objects – it is vital to have a free line of sight between 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, keyboards, etc. are potential sources of interference. They produce high-frequency harmonics,
and are therefore totally unsuitable for use
near the antennas of wireless systems. The
minimum distance between walls and antennas 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 carrier frequency band (UHF or VHF), and placing the antenna(s) carefully to prevent any
dead spots. If none of the above methods
alone improves the situation, try them in different 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 transmitter! But seriously, even professionals have
made this mistake in the commotion of setting 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.
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AKG WMS BASICS
HOW WIRELESS TECHNOLOGY WORKS
HOW RADIO SIGNALS ARE TRANSMITTED
Wireless transmission technology is based on
the physical principles governing the propagation of electromagnetic waves. Radio, television, mobile telephone communications, microwaves, and light are all based on electromagnetic waves with different wavelengths.
Short waves have completely different characteristics, and are propagated as high-frequency 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 science-fiction movie (climbing into a radio-frequency signal), because the physical laws
that now come into effect are similar to the
highway code of the future! This metaphorical example is not entirely analogous to the
physical reality, but it may give a clearer picture.
What happens to our audio signal once it has
entered our metaphorical taxi in order to travel 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 journey, but have to share the roads with a number 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 traffic jams. These other signal waves continually 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 transmitting 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 maximum number of channels that can be operated simultaneously varies depending on
national licensing regulations.
The licensing regulations issued by the relevant regulatory authorities for telecommunications 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.
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.
8 www.akg.com
Bandwidth
Every frequency-modulated carrier signal does not oscillate
entirely within the frequency allocated to it, but also occupies 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 signals should therefore be far enough apart to prevent their
bandwidths from overlapping.
AKG WMS BASICS
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 quality. This involves imposing an audio signal on a radio-frequency (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 changes in the RF carrier signal (transmission frequency).
Therefore, this technique is known as “frequency modulation”.
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 information. The maximum permissible number of channels may
vary depending on national frequency plans.
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 possible for two or more systems to work on the same frequency. Even if the frequencies are different, one must always
ensure that there is sufficient separation between the frequencies 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 PRO, SO 40, MP 40, and GB 40 transmitters are
removable, and can be replaced by the black clip provided.
www.akg.com 9
AKG WMS 40 PRO OVERVIEW
THE WMS 40 PRO MODULAR SYSTEM
COMPRISING ALL FLEXX, DUAL AND SINGLE LINES, MODULAR SOLUTIONS
COMPLETE SYSTEMS TO MEET INDIVIDUAL REQUIREMENTS
AND
The requirements of wireless systems vary
from one user to another. This calls for individual solutions, which is why AKG has created the WMS 40 PRO series as a modular system that offers a wide range of solutions
depending on the user’s preferences and chosen field of application.
Different users require different features from
a wireless system. This calls for individual
solutions, which is why AKG has created the
WMS 40 PRO series as a modular system that
offers a wide range of solutions depending on
the user’s preferences and chosen field of
application.
The WMS 40 FLEXX system allows you to use
up to nine* channels simultaneously, and its
VOCAL SET FLEXX VOCAL SET DUAL
SR 40 FLEXX
receiver
HT 40 FLEXX
handheld transmitter
Vocals
up to 30 hours of battery life, true diversity
reception, and exceptional audio quality are
features normally encountered in professional
equipment only.
The WMS 40 DUAL line of complete systems
provides probably the most compact solutions
where a single channel is not enough while a
true multichannel system would be too much.
Each DUAL line box contains two complete
receivers in a single unit and two transmitters
so you can set up and use two totally independent microphone channels with no need to
adjust lots of controls or worry about complex
wiring. The DUAL systems, too provide extralong battery life, maximum audio quality, and
unique price/performance ratios.
SR 40 DUAL
receiver
2 x HT 40 PRO
handheld transmitter
The WMS 40 SINGLE systems are simple,
functional single-channel setups that make it
incredibly easy for anyone to make the change
to wireless. The WMS 40 SINGLE being a
modular system, you can even set up more
complex systems with up to seven* channels.
Talking about modules, the WMS 40 microtools Series transmitters are of course fully
compatible with the WMS 40 PRO line and so
versatile we'd run out of space if we tried to
mention all the applications they can be used
for.
Have fun selecting your personal WMS 40
PRO system!
VOCAL SET SINGLE
SR 40 SINGLE
receiver
HT 40 PRO
handheld transmitter
INSTRUMENTAL SET FLEXX
SR 40 FLEXX
receiver
PT 40 FLEXX
bodypack
transmitter
MKG L cable MKG L cable
Instruments
INSTRUMENTAL SET DUAL
SR 40 DUAL
receiver
2x MKG L cable
2 x PT 40 PRO
bodypack transmitter
INSTRUMENTAL SET SINGLE
SR 40 SINGLE
receiver
SPORTS SET FLEXX
SR 40 FLEXX
receiver
PT 40 FLEXX
bodypack
transmitter
C 444 L
head-worn microphone
SR 40 SINGLE
receiver
Sports
PRESENTER SET
SR 40 FLEXX
receiver
Presenter
CK 55 L
lavalier microphone
FLEXX
PT 40 FLEXX
bodypack
transmitter
PRESENTER SET
SR 40 DUAL
receiver
C 444 L
head-worn
microphone
DUAL
PT 40 PRO
bodypack
transmitter
HT 40 PRO
handheld
transmitter
SR 40 SINGLE
receiver
PT 40 PRO
bodypack
transmitter
SPORTS SET SINGLE
PT 40 PRO
bodypack
transmitter
C 444 L
head-worn microphone
PRESENTER SET SINGLE
PT 40 PRO
bodypack
transmitter
CK 55 L
lavalier microphone
* Depending on available frequencies under local frequency plans. Ask your dealer for details or visit our website at www.akg.com/wms40pro
10 www.akg.com
Guitar Special
GUITAR/VOCAL SET DUAL
SR 40 DUAL
receiver
GB 40
guitarbug
AKG WMS 40 PRO OVERVIEW
PT 40 PRO
bodypack transmitter
C 444 L
head-worn microphone
GB 40
guitarbug
SO 40
snapon transmitter
microtool SO 40 microtool GB 40
SR 40 FLEXX
receiver
SR 40 SINGLE
receiver
PR 40
receiver
+or or
+
+
SR 40 FLEXX
receiver
SR 40 FLEXX
receiver
SR 40 SINGLE
receiver
or or
SR 40 SINGLE
receiver
or or
PR 40
receiver
PR 40
receiver
MP 40
micropen
microtool MP 40
TM 40
transmitter module
microtool TM 40
PR 40
receiver
+ choose from
microtool PR 40
+
SR 40 FLEXX
receiver
SR 40 SINGLE
receiver
or or
PR 40
receiver
www.akg.com 11
AKG WMS 40 PRO VOCAL SYSTEMS
AKG WMS 40 PRO FOR VOCALS
MICROPHONE SYSTEMS FOR LEAD AND BACKING VOCALS
The HT 40 PRO handheld transmitter is an
excellent choice for both handheld and standmounted 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 HT 40 PRO handheld transmitter is an
excellent choice for both handheld and standmounted 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.
VOCAL SET FLEXX
Maximum flexibility
Three selectable frequencies for interference-free
reception, input gain control on transmitter.
• Single channel with three selectable frequencies
• Diversity receiver
• Adjustable squelch
• Multichannel capability for using up to nine*
channels simultaneously
• Rugged construction
We've put together several complete systems
from the various WMS 40 PRO lines to provide a perfect solution for every application that
installs and sets up in no time. The challenge
was to provide a system for every vocal application. The WMS 40 PRO vocal systems are
the perfect answer.
The FLEXX vocal system comprising an HT 40
FLEXX and SR 40 FLEXX is probably the most
powerful wireless system in its price bracket.
Three selectable frequencies, diversity reception, and multichannel capability up to nine*
channels are features typical of more costly
professional systems.
VOCAL SET DUAL
Dual-channel receiver, low operating cost
The cost efficient way to use two transmitters simultaneously.
• Two fixed-frequency receivers in a single unit
• Metal case
• Miniature transmitters
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
The DUAL vocal system including the revolutionary SR 40 DUAL receiver and two HT 40
PRO handheld transmitters is the ideal choice
for vocal duos who want to get going quickly
with a minimum of equipment.
The SINGLE vocal system is a basic fixed-frequency, single-channel setup. Unpack the
transmitter and receiver, connect, and play.
With its compact, rack-mountable receiver,
the AKG WMS 40 PRO is an easy-to-use, convenient wireless system, and once you tried it
you won't want to do without it anymore.
SR 40 FLEXX
receiver
HT 40 FLEXX
handheld transmitter
SR 40 DUAL
receiver
Rack mounting
All SR 40 PRO receivers can be used either free-standing or
rack mounted. An optional rack mounting kit allows you to
install one or two receivers quickly and easily on a single
level of any 19" rack. The half-rack, 1 U case lets you mount
the receivers for a complete six-piece band in just 3 U of
rack space.
2 x HT 40 PRO
handheld transmitter
12 www.akg.com
AKG WMS 40 PRO VOCAL SYSTEMS
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 significantly 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.
VOCAL SET
Plug and play
The perfect choice for a single wireless microphone
channel. Unpack and get going.
• Single fixed frequency
• Metal case
• Miniature transmitter
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
SINGLE
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.
HT 40 PRO
handheld transmitter
SR 40 SINGLE
receiver
Microphone cleaning and maintenance
Microphones, like any other instrument, need regular cleaning 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 transparent 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.
www.akg.com 13
AKG WMS 40 PRO INSTRUMENTS
AKG WMS 40 PRO FOR INSTRUMENTS
RADIO LINKS FOR PORTABLE INSTRUMENTS
More and more musicians prefer wireless
microphones, so AKG was asked to create
a wireless system specifically for "minimally invasive" miking of acoustic instruments with no on-board pickup. The
proven AKG MicroMic Series microphones
in conjunction with the AKG PT 40 PRO
bodypack transmitter and SR 40 PRO
portable receiver provide a solution offering exceptional quality, price/performance, and flexibility. Since the high
quality MicroMic Series microphone capsules require high-performance production
INSTRUMENTAL SET FLEXX
Maximum flexibility
Three selectable frequencies for interference-free
reception, input gain control on transmitter.
• Single channel with three selectable frequencies
• Diversity receiver
• Adjustable squelch
• Multichannel capability for using up to nine*
channels simultaneously
• Rugged construction
lines they are made at the AKG factory in
Vienna, Austria. Expensive UHF technology has been optimized for the specific
requirements of wireless systems for
smaller venues such as clubs, rehearsal
rooms, or local community centers.
The WMS 40 PRO provides fully professional audio and UHF transmission quality adjusted to the needs of musicians on a
budget. The MicroMic Series includes a
wide choice of small, light microphones
designed for easy mounting on various
instruments and liberates musicians from
the constraints imposed by stand-mounted
microphones.
Of course, all MicroMics will leave no trace
on the instrument when you remove them.
PRO
Using an AKG WMS 40
tem with AKG MicroMic Series microphones is an optimum solution for acoustic
guitar, violin, banjo, zither, accordion, various wind instruments, and many other
applications. Each instrument system
includes an MKG L cable.
wireless sys-
PT 40 FLEXX
bodypack transmitter
SR 40 FLEXX
receiver
Rear panel and battery compartment
Viewing window for checking the battery type.
Frequency and color code label for easy frequency identification
in a multichannel system.
Frequency selector for easy tuning to one of the three preset
frequencies.
GAIN matches the sensivity of the transmitter’s audio section to
the output level of the connected instrument.
MKG L cable
14 www.akg.com
AKG WMS 40 PRO INSTRUMENTS
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 distinguish between wanted signal and noise. Besides that, a too
high squelch treshold also decreases the usable range.
INSTRUMENTAL SET DUAL
Dual-channel receiver, low operating cost
The cost efficient way to use two transmitters simultaneously.
• Two fixed-frequency receivers in a single unit
• Metal case
• Miniature transmitters
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
INSTRUMENTAL SET
Plug and play
The perfect choice for a single wireless microphone
channel. Unpack and get going.
• Single fixed frequency
• Metal case
• Miniature transmitter
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
SINGLE
SR 40 DUAL
receiver
SR 40 SINGLE
receiver
2 x PT 40 PRO
bodypack transmitter
PT 40 PRO
bodypack transmitter
MKG L cable
2 x MKG L cable
MicroMic C 411 L pickup
For guitar, violin, viola, banjo, zither, or hammered dulcimer.
Fix the pickup near the bridge (left).
C 419 L instrument MicroMics
For saxophone, clarinet, tubas, trombone, trumpet (right).
C 416 L instrument MicroMic
To mic up an accordion, use two AKG C 416 L with a B 29L
battery supply/mini mixer (left).
C 420 L head-worn MicroMic
For flute and harmonica (right).
For detailed hints on using MicroMics refer to pages 70/71.
www.akg.com 15
AKG WMS 40 PRO PRESENTERS
AKG WMS 40 PRO FOR PRESENTERS
WIRELESS SYSTEMS FOR INSPIRING LECTURES
The WMS 40 PRO presenter systems have
been put together specifically for presentations, lectures, or video recording.
The FLEXX presenter system is a high quality wireless system for cost-conscious lecturers who insist on fail-safe reliability and
expandability. Diversity reception, three
selectable frequencies, adjustable squelch,
and the proverbial AKG audio quality provide
interference-free, perfect intelligibility. And
if the need arises, the setup can be expanded to a maximum of nine* channels. The
heart of the system is the CK 55 L high quality lavalier microphone.
PRESENTER SET FLEXX
Maximum flexibility
Three selectable frequencies for interference-free
reception, input gain control on transmitter.
• Single channel with three selectable frequencies
• Diversity receiver
• Adjustable squelch
• Multichannel capability for using up to nine*
channels simultaneously
• Rugged construction
PT 40 FLEXX
bodypack
transmitter
The CK 55 L cardioid lavalier microphone has
been optimized for the speech frequency range
and has an excellent track record. It is so small
it becomes nearly invisible on the user.
The SINGLE system includes this microphone, too. The transmitter and receiver
make up a typical fixed-frequency, "plug and
play" system that is extremely easy to use.
Upgrading at a later date is easy, too: the
SINGLE has been designed so you can add
up to six* channels to your first channel at
any time.
The DUAL setup is a completely new product
PRESENTER SET SINGLE
Plug and play
The perfect choice for a single wireless microphone
channel. Unpack and get going.
• Single fixed frequency
• Metal case
• Miniature transmitter
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
bundle optimized for presenters who like to
interact with their audiences. Two independent receivers in a single unit will simultaneously process the signals from the C 444 L
microphone worn by the presenter and the
handheld microphone used by a person from
the audience. This is about as convenient,
simple, and cost efficient as it gets.
The MP 40 micropen is an ultra-compact
microphone that can be used handheld or in
lavalier mode remotely from the transmitter.
Together with the PR 40 portable receiver,
the MP 40 pen-size microphone is probably
the smallest ENG system in the world.
PT 40 PRO
bodypack
transmitter
SR 40 FLEXX
receiver
CK 55 L
lavalier microphone
SR 40 SINGLE
receiver
CK 55 L
lavalier microphone
C 444 L
A flexible plastic behind-the-neck arch and large support
pads resting gently against the head keep the C 444 L
securely in place without pinching.
The flexible microphone arm absorbs mechanical impact
and places the microphone near the corner of the user's
mouth to prevent pop and breathing noise from being
picked up as it would if the mic were positioned right in
front of the mouth.
16 www.akg.com
AKG WMS 40 PRO PRESENTERS
Detachable microphone
Where gain before feedback is no problem, leave the microphone safely nested in its compartment. In more acoustically difficult environments, remove the microphone from the
transmitter and attach it to the clothes nearer the user's
mouth using the crocodile clip on the microphone.
Put it in your pocket …
… like a ballpoint pen. You can replace the colored clip
with an inconspicuous black clip if necessary.
PRESENTER SET
Dual-channel receiver, low operating cost
The cost efficient way to use two transmitters simultaneously.
• Two fixed-frequency receivers in a single unit
• Metal case
• Miniature transmitters
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
DUAL
MP 40 micropen with detached microphone
To improve intelligibility, you can use the integrated cable
and crocodile clip on the microphone to attach the microphone to the clothes, near the user's mouth. Reception conditions permitting, you can even hide the transmitter in an inside pocket.
SR 40 DUAL
receiver
C 444 L
head-worn
microphone
MP 40 micropen in handheld mode
For interviews, etc., you can use the MicroPen in the same
way as a conventional handheld microphone. Remember,
though, that the sensitivity of the MP 40 is higher than that
of most conventional models.
PT 40 PRO
bodypack transmitter
HT 40 PRO
handheld transmitter
CK 55 L
The CK 55 L is a lavalier microphone with an excellent
price/performance ratio. With its extended frequency
response, this cardioid condenser microphone is a perfect
tool for talkers or presenters who need to keep their hands
free.
www.akg.com 17
AKG WMS 40 PRO GUITAR SPECIAL
AKG WMS 40 PRO FOR GUITARS
GB 40 GUITARBUG FOR GUITAR AND BASS + PT 40 PRO AND C 444 L FOR VOCALS
Too long. Too short. Forgot it. Tied up in
knots. Tangled up. Gone. Pins reversed.
Disconnected. Broken. Must be hard to find
a guitarist or bassist who never got furious
about their cables and the related mess.
The convenient alternative from AKG is called the GB 40 guitarbug, a WMS 40
Microtools Series miniature transmitter specifically designed for guitars and basses. It
matches any instrument with a 1/4" TS
jack, including keyboards. The spring-loaded "FlexJack" swiveling jack plug connects
to the instrument and pulls the transmitter
against the instrument. The soft-touch coa-
GUITAR SPECIAL DUAL
Dual-channel receiver, low operating cost
The cost efficient way to use two transmitters simultaneously.
• Two fixed-frequency receivers in a single unit
• Metal case
• Miniature transmitters
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
ting on the transmitter bottom panel stabilizes the transmitter on the instrument and
prevents the instrument surface from being
scratched.
The DUAL guitar system includes a convenient GB 40 guitarbug, a C 444 L headworn microphone for singing guitarists/bass
players, a PT 40 PRO bodypack transmitter
plus the revolutionary SR 40 DUAL receiver,
actually two complete, totally independent
fixed-frequency receivers in a single case.
This simple, compact, and reliable twochannel system sets up and is ready to operate in just a few minutes, and you can add
SR 40 DUAL
receiver
C 444 L
head-worn microphone
up to six* more channels of WMS 40 PRO
to your first channel if required.
This system combines unlimited mobility
on stage, ultra-compact dimensions, ease
of use, and exceptional dependability, proverbial AKG audio quality, and more than
30 hours of transmitter operation off a
single AA size battery for unique cost efficiency.
All these features make the WMS 40 PRO
DUAL guitar system one of the cleverest
setups for singing guitarists as well as bass
and keyboard players.
GB 40
guitarbug
FlexJack for all electric/acoustic guitar models
The FlexJack connects to guitar jacks in the strap button.
FlexJack for all electric guitar models
The FlexJack connects to guitar jacks on the side (left) or top
(right).
FlexJack for all electric bass models
The FlexJack connects to bass jacks on the side or top.
PT 40 PRO
bodypack transmitter
FlexJack for all portable keyboards
The FlexJack connects to keyboard jacks. Use two WMS 40
systems for a stereo keyboard.
18 www.akg.com
AKG WMS 40 PRO SPORTS
AKG WMS 40 PRO FOR SPORTS
WIRELESS SYSTEMS FOR MAXIMUM MOBILITY
Wireless microphone systems are becoming increasingly popular in sports arenas,
fitness or dance studios for efficient communication between athletes and trainers.
The WMS 40 Sports System is a complete
solution designed for the specific needs of
athletes and trainers.
The FLEXX sports system stands out for its
fial-safe dependability, three selectable
frequencies and adjustable squelch. For
large teams with several trainers and assistants, the system can be expanded to as
many as nine* channels.
The SINGLE package is a simple, reliable,
and highly cost efficient solution for any
application where a single, fixed-frequency
channel fits the bill. However, you can add
another six* channels at any time if the
need arises.
The PT 40 bodypack transmitter features a
belt clip for easy and secure fastening to
the user's belt or clothes. Alternatively, you
can use the supplied light, padded neoprene bag that protects the transmitter
from perspiration and impact.
SPORTS SET FLEXX SPORTS SET SINGLE
Maximum flexibility
Three selectable frequencies for interference-free
reception, input gain control on transmitter.
• Single channel with three selectable frequencies
• Diversity receiver
• Adjustable squelch
• Multichannel capability for using up to nine*
channels simultaneously
• Rugged construction
Plug and play
The perfect choice for a single wireless microphone
channel. Unpack and get going.
• Single fixed frequency
• Metal case
• Miniature transmitter
• Single-battery powering
• Multichannel capability for using up to seven*
channels simultaneously
Wireless microphones can be used for
many applications from training at the gym
to championships in any sports, for communication between trainers and athletes
or direct connection to the sound system
at a stadium.
The WMS 40 Aerobics System provides tailor-made speech reinforcement solutions
for gyms, sports clubs, and teams that are
easy to connect to an existing sound system at a gym, hall, or open-air arena, and
guarantee users the required mobility.
C 444 L
head-worn microphone
SR 40 FLEXX
receiver
PT 40 FLEXX
bodypack transmitter
C 444 L
head-worn microphone
SR 40 SINGLE
receiver
CB 400 for optimum bodypack protection
Particularly when used by gymnastics trainers, the PT 40 is not only subjected to mechanical stress but above all the
corrosive effects of perspiration. Therefore, you should always use the PT 40 with the supplied neoprene bag.
Should this be impossible for some reason, wear the PT 40 with the antenna pointing down if you use it with a headworn microphone. This will prevent perspiration from creeping along the cable and finding its way into the transmitter.
PT 40 PRO
bodypack transmitter
www.akg.com 19
AKG WMS 40 CUSTOMIZING
AKG WMS 40 SPECIAL PRODUCTS
PUT TOGETHER YOUR OWN CUSTOM SYSTEM
Although the many WMS 40 PRO FLEXX,
SINGLE, and DUAL Series systems cover
a wide range of applications, situations
may come up now and then that require
more specialized devices.
Frequent inquiries from users about
handsfree microphones, upgradability of
existing components, or maximum flexibility prompted AKG to design the WMS
40 microtools. Packing an incredible
number of features into incredibly little
space, each microtool is a miracle of
miniature wireless technology.
The GB 40 guitarbug is probably the most
popular microtools Series transmitter.
Small wonder, for it is the ideal solution
for any guitarist or bass player who has
had enough of cables getting in the way.
All you need to do is plug it into the output jack on your instrument and power up.
With a capacity of up to eleven hours, the
battery will outlast even the longest gig,
and the input gain control allows you to
match the audio input gain perfectly to
your pickup model and playing technique
to prevent overmodulation or dropouts.
And all this weighs less than even the
shortest of cables.
Talking about cables, many users of hardwire microphones may wish to go on stage
without having to worry about a cable. But
what if your favorite microphone is not or
no longer available in a wireless version?
Don't worry: the SO 40 snapon transmitter
simply connects to the XLR output on your
microphone, turning it into a handheld
transmitter on the spot. What's more, if
your microphone has no mute switch, you
can use the one on the transmitter!
Inspired by the snapon transmitter idea,
AKG engineers began to think again
about the hot selling Emotion and TriPower Series microphones. The result is
as simple as it is surprising. Several different plug-in modules with or without an
on/off or gain and bass cut switches allow
these microphones to be used either in
hardwire mode (e.g., for miking up an
amplifier) or in wireless mode, simply by
plugging in the elegant TM 40 transmitter
module.
The MP 40 micropen is a highly versatile,
compact tool for all ENG applications as
well as for lecturers. The engineers and
designers at AKG achieved the incredible
feat of packing the combined features of a
lavalier microphone connected to a
remote wireless transmitter, a pen-size
clip-on microphone, and a handheld
microphone into a space as small as two
throwaway lighters. And, even more
incredibly, all this weighs no more than
36 grams (1.3 oz.).
All microtools can be used with all WMS
40 PRO Series receivers or the compact
PR 40 portable receiver. This receiver
continues the miniaturization begun by
the microtools transmitters. Although it is
as small as a conventional bodypack
transmitter, the battery operated PR 40
offers features that are considered
advanced even on stationary receivers:
diversity, two swiveling antennas, an
adjustable squelch, status LEDs, an output level control, and a headphone output.
Any combination of a microtool and PR 40
receiver could actually be called a "pocket
radio link" as you could put any microtools
Series transmitter and a portable receiver
in your coat pocket together. And the
entire system needs no power outlet,
either. Both the transmitters and the
portable receiver are battery powered, and
with a battery life of up to six hours for the
receiver and up to eleven hours for the
transmitter, there will be enough power for
jobs taking many hours on end.
The AKG WMS 40 microtools Series
stands for ultra-compact, ultra-portable
wireless technology.
receivers WMS 40 microtools accessories
SR 40 SINGLE
stationary receiver
PR 40
portable receiver
GB 40 guitarbug
FlexJack swiveling,
extendible plug matches
all guitar and bass jacks.
MP 40 micropen
Clever, easy-touse clip-on microphone for lecturers,
moderators, and trainers.
CU 40
charger
++
SO 40 snapon transmitter
Turns every
hardwire microphone
into a wireless transmitter.
TM 40 transmitter module
Special plug-in transmitter module for
M
, D 3800M, C 5900M,
D 3700
M
, and C 900MTri-Power
D 880
and Emotion Series microphones.
CU 400
charger
20 www.akg.com
AKG WMS 40 CUSTOMIZING
D 3700
D 880
M
D 3800
M
C 5900
M
Wireless and highly flexible
The TM 40 can be used with all Emotion and Tri-Power
Series microphones including the D 3700Mcardioid and
D 3800Msupercardioid dynamic microphones, the
C 5900Msupercardioid condenser microphone, the D 880
M
cardioid dynamic, and the C 900Mcardioid condenser
microphones. The right microphone for every budget and
every application on stage, easily convertible from hardwire to wireless.
M
C 900
M
Choice of XLR modules
Several XLR connector modules are available for hardwire
operation. Gold plated contact pins ensure maximum audio
quality. XLR modules with or without an on/off switch are
available for the D 880M, D 3700M, and D 3800Mdynamic
microphones. The XLR module for the C 900Mcondenser has
no switch, and the XLR module for the C 5900Mcondenser
provides output level and bass cut switches. These modules
can convert a wireless microphone into a hardwire version
within seconds.
PR 40 portable receiver
Antennas
The swiveling antennas can be set to any
angle.
Bottom panel charging contacts
The charging contacts allow you to charge
the batteries inside the PR 40 using the
optional CU 40 quick charger.
Volume
Sets the volume level of the headphone output
and matches the output level
to the mixer input level.
ON/OFF switch
with status LED.
RF LED
Illuminates to indicate that RF signal is being
received. If the RF signal fails or the squelch
comes on, the RF LED will go out.
Case
Featuring an exceptionally light and compact case, the PR 40 can be easily attached to a belt, camera, pedalboard, etc.
using the belt clip or supplied Velcro strip.
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AKG WMS MULTICHANNEL TECHNOLOGY
HOW MULTICHANNEL TECHNOLOGY WORKS
FREQUENCY MANAGEMENT, INTERFERENCE, AND PRACTICAL REMEDIES
A knowledge of the laws of physics governing
the propagation of radio waves is essential if
one is to gain maximum benefit from the advantages of wireless transmission technology.
Radio waves are electromagnetic waves that
are used as a carrier for the transmission of
signals.
In physical terms, electromagnetic waves
transport energy through space. In a vacuum,
they are propagated at the speed of light (in
other media almost the speed of light,
300,000 km/s). The relationship between frequency and wavelength is defined by the following equation:
l = c/f
(wavelength = speed of light / frequency)
The speed of electromagnetic waves and their
ability to pass through obstacles varies depending on their wavelength. Due to the growing
popularity of wireless communications such as
wireless, radio/television broadcasting, mobile
telephony, and wireless LAN networks, the
density of the radio signals around us is rapidly increasing (see illustration below). Consequently, there is also a greater risk of disturbances caused by RF interference and electrosmog.
Dropouts are the result of zero RF field strength
at a receiving antenna. One reason may simply be excessive separation between transmitter
and receiver so the receiver will capture no sig-
nal. Another reason may be multipath reception: as the signal is reflected several times,
the resulting multiplied signals arrive at the
receiving antenna from different directions and
in different phases. When this occurs, they
may cancel one another out, resulting in signal
dropout. Another type of dropouts may be caused by interference that will become audible as
noise if the carrier signal is sufficiently weakened. In order to prevent this, most receivers are
equipped with a muting circuit. Provided this
circuit is fast enough, and the muting threshold is just above the electrosmog level, it can
switch off the audio circuit whilst the signal
level drops as described above. It is not possible to completely suppress dropout, which is
often accompanied by a crackling sound.
The best way to prevent interference is to eliminate the source of unwanted signals such as
computers. If this is not possible, the solution
may be switching the microphone system to
another radio frequency (see illustration above
right).
Electrosmog is generated by electronic equipment such as lighting systems, computers, and
other digital equipment. In practice it is advisable to keep as far away as possible from
lighting equipment, computers, fax machines,
etc., and not to install other electronic equipment in a rack along with the wireless microphone unit. If interference occurs, the usual
solution is to switch to another frequency.
Apart from intermodulation and digital noise,
the electro-smog inherent in a multichannel
system is the sideband noise of the transmitters and receivers. Even the best oscillator is
unable to generate a signal entirely without
phase shift, consisting of a single, infinitely
narrow spectral line. All oscillators have a noise
skirt whose spectral density decreases with
increasing frequency separation from the line.
In the case of carrier signals on adjacent frequencies, the noise skirts and the carriers may
overlap. For example, if a performer with a
transmitter gets very close to the receiving
antenna, it is possible for the sideband noise to
open a muted channel. This can be avoided
only with the aid of an additional tone-coded
squelch circuit.
In practice it is advisable to keep as far away
as possible from lighting equipment, and not to
install other electronic equipment in a rack
along with the wireless microphone unit. If
interference occurs, the usual solution is to
switch to another frequency.
Where several wireless systems are to be used
simultaneously in the same place, interference
may result from intermodulations due to the
non-linear distortion of combined carrier frequencies (see illustration on the right).
Like most other wireless microphone systems,
AKG WMS systems use frequency modulation.
This involves changing (modulating) a carrier
frequency in step with an audio signal (see also
WMS 40, page 9).
22 www.akg.com
The electromagnetic
wave spectrum
The electromagnetic wave spectrum
is becoming increasingly crowded by
a wide variety of applications.
Wireless microphones generally share
the same frequency range as television broadcasts. Allocated bands for
UHF wireless microphones are within
the 470 to 862 MHz range, in Europe
650 to 863 MHz and in the United
States 470 to 806 MHz.
AKG WMS MULTICHANNEL TECHNOLOGY
WMS frequency band with TV transmitter
If you are faced with interference caused by a television station, select the carrier frequency of the wireless microphone system such that there is a separation of at least 500 kHz from
the video carier, and 200 kHz from the audio carrier. Caution: changing a single carrier frequency may result in chaotic intermodulation in the entire multichannel system!
The Frequency Management Program from AKG provides a simple solu-tion to this problem as it automatically finds frequencies that wll not interfere with one another.
Intermodulation
The nonlinear characteristics of a transmission link may
cause intermodulation problems. Intermodulation products do not increase linearly as f1 and f2 rise in amplitude
of, but significantly faster. 3rd order intermodulation artifacts are the biggest problem that beset wireless systems,
as they are strong enough to be clearly received.
Intermodulation
The simultaneous use of several radio sources results in
intermodulation products in the frequency spectrum. If, for
example, a third radio source (microphone) is used on the
same frequency as that of a 3rd order intermodulation product of microphones A and B, microphone C is very likely
to pick up a lot of intermodulation noise. This is why it is
essential to test all the radio frequencies you wish to use
before each performance.
The Auto Setup function performs this text automatically.
www.akg.com 23
AKG WMS MULTICHANNEL TECHNOLOGY
HOW MULTICHANNEL TECHNOLOGY WORKS
FREQUENCY MANAGEMENT, INTERFERENCE, AND PRACTICAL REMEDIES
Interference due to intermodulation can occur
as soon as a radio-frequency circuit consisting
of semiconductors or ferrites – like that of a
WMS receiver – handles several RF signals at
different frequencies. The number of disturbing
frequencies (intermodulation products) increases exponentially wherever several radio links
(frequencies) are used simultaneously. This
laws of physics have the biggest impact when
several radio microphones are used at the same
time. The innumerable new frequencies generated by the combination, addition and subtraction of the desired frequencies cause additional
interference. Expert management of the frequencies of all radio sources designed to be
used simultaneously is therefore absolutely
essential for the problem-free operation of a
multichannel wireless system.
Incorrect positioning of the antennas and receiver is just as frequently a source of undesirable
interference. It is essential to ensure a minimum distance of 5 feet (1.5 m) from large
metal objects such as lighting gantries and
stage decorations (especially wire mesh). You
should also avoid placing antennas in wall
niches to prevent shadowing. Radio signals
reflected or shadowed by walls, ceilings or
metal structures also weaken the useful signal,
thus resulting in improper functioning of the
radio equipment (see WMS 40 illustration on
page 6/7). The interference from electrical
appliances that cause electrosmog (such as
computers and lighting equipment) can be particularly disturbing during deep fades. During a
deep fade that changes only slowly, a tone code
squelch prevents unwanted noise from lasting
too long.
On the other hand, a conventional muting circuit is unable to differentiate between “friend”
(the right frequency) and “foe” (unwanted signals). If the level of interference is too high, it
may interrupt the audio path during noisy deep
fades. Most receivers use both types of circuit:
a fast muting circuit to eliminate short bursts of
noise, and a tone code squelch to reject persistent noise. Since both types of circuit act like a
hard gate on the audio signal, there will always
be some residual switching noise.
To ensure problem-free operation, always observe the following basic rules when setting up
a multichannel wireless system as opposed to a
single channel application. Always position the
receiving antennas within the far-near difference range (see page 45). Nevertheless, make
sure there is always an unobstructed line of
sight between the transmitter and receiver
during the performance. Also, the better the
audio signal fed to the transmitter and the higher the signal/noise ratio of the transmitter and
receiver, the better your wireless system will
work. Basically you should always set the transmitter audio input gain first. The signal-to-noise
ratio is the ratio between the amplitude of the
wanted signal and the noise amplitude; it is a
logarithmic expression for the purity of a signal.
With radio transmission, the signal/noise ratio
depends on the amplitude of the audio signal.
The stronger the audio signal, the better the signal-to-noise ratio. This is why it is always a good
idea to make sure not to set the audio input
gain of the transmitter too low.
In order to enhance the signal/noise ratio, the
audio signal passes through a pre-emphasis circuit in the transmitter and a corresponding deemphasis circuit in the receiver. The amplitude
of the signal is not evenly distributed over the
frequency spectrum. Higher frequencies have a
lower amplitude than lower frequencies, resulting in a lower signal-to-noise ratio for higher
frequencies than for lower ones. FM demodulation generates more high-frequency noise. The
pre-emphasis circuit boosts higher frequencies
ahead of the radio link, whilst the de-emphasis
circuit in the receiver attenuates them by a corresponding amount.
Automatic frequency setup
During concerts and other performances, a number of appliances emit electromagnetic waves that may disrupt your transmission channels (outside interference). Thanks to the
“Environment Scan” function, AKG wireless systems are able to
localize such “jammers”, switching to suitable interference-free
frequencies instead.
In other words, the system automatically searches for gaps in
the fre-quency spectrum – that is, frequencies where no interference is de-tected – occupying them with its own carrier frequencies.
Important: Run Environment Scan during the soundcheck and
note the results. Do another test shortly before the performance,
as there will almost certainly be new sources of interference,
such as television and radio transmitters, or mobile phones in
the audience. This gives you time to correct any problems that
may have arisen.
24 www.akg.com
AKG WMS MULTICHANNEL TECHNOLOGY
Shadow loss:
Shadow loss means that the signal path from the transmitter to the antenna is interrupted by an obstacle.
Diversity systems help to eliminate transmission problems caused by shadow effects or multipath transmission.
Multipath transmission:
A radio signal travels to the receiver not only along the direct path but also along several
alternative routes as the signal is reflected off or diffracted around all kinds of structures. So
the same signal arrives at the receiver at different points in time and in different conditions.
Non Diversity
Wireless systems with a non-diversity receiver have to process the signal in whatever shape it reaches the antenna.
Even with moderate distances between transmitter and
receiver, this results in more frequent – and therefore very
disturbing – periods of signal dropout.
Dual antenna diversity
When the RF signal level of the antenna path being used
becomes too low, the switching circuit connects the receiver input to the other antenna. If this fails to provide a
higher signal level, the switching circuit reverts to its original position. The disadvantage of this system is that it
only checks whether the RF signal level of the second
antenna is higher once the level at the first antenna is
already too low. Differences in the signal/noise ratio are
not even detected at all.
www.akg.com 25
True diversity technology
In contrast to antenna diversity, true diversity not only
employs two antennas, but two receivers as well. The
switching circuit compares the quality of the two signals
and routes the better signal to the output.
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