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| Eurovision Song Contest : RF Wireless Transmission as a Balancing Act |
Achieving the (almost) impossible: Sennheiser RF wireless mics will ensure
first-class sound under the adverse RF conditions at the
Copenhagen Song Contest |
On May 12, this year’s Eurovision Song Contest will see 48 RF wireless mics (plus 16 IEM channels) go live on air for a three-hour music broadcast. More than 300 million viewers in 23 countries will watch the event live, with an
audience of around 35,000 witnessing the contest in Copenhagen’s Parken Stadium. The contest itself will have been preceeded by a 4-week installation and rehearsal phase. During this period, the teams of the Danish
Broadcasting Company, Danish Sennheiser partner Kinovox and RF specialists from the Sennheiser head office in Germany are cooperating closely to meet a whole constellation of challenges. Artists will perform with
Sennheiser’s top-of-the-range 3000 and 5000 Series, which experts consider the benchmark in RF wireless transmission.
The Copenhagen Challenge
The Eurovision Song Contest in Denmark is the first ever to be held open air, in a sports arena whose stage was especially fitted with a glass roof. Usually, such shows are hosted in large indoor venues, where walls
and ceiling provide a certain protection against interfering outside RF sources such as local radio and TV stations and RF communication services. The RF links in the Parken Stadium will not benefit from such ”interference protection”.
In a ”solid” hall, reflections by the ceiling help to propagate the RF signal. A glass roof, however, does not reflect RF frequencies. The signals just travel through it. The receivers in the Parken will therefore capture RF signals with less signal strength than in a hall with a solid ceiling.
In the Parken Stadium, the stage show will be displayed on six huge LED screens. They are not fixed, but will be moved during the show. These screens are not shielded, so they produce spurious radiation whose
frequency spectrum reaches into the UHF range. The interference power of such a screen can easily exceed the output power of a bodypack transmitter. As there is no possibility to shield the screens, the only solution
is to keep the receivers ”well away” from the screens and to optimize the directional properties of the antennas.
Of course there are also the usual sources of interference, such as digital audio effects units and lighting controls.
The trouble shooting strategy can only turn to standard measures, such as:
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|  | Staying at a distance from the sources of interference
| | Finding optimum positions for the transmitting and receiving antennas
| | Taking advantage of directional properties. |
Frequency Management
In assigning the 48+16=64 RF channels required for the event, the engineers had to comply with national Danish regulations on the one hand and to use the ”frequency gaps” which were not occupied by TV and radio stations
and RF communication services on the other. Once the 64 channels were found, they were allocated to 6 frequency windows with sufficient spacing. Despite all adverse conditions, the resulting system has an RF
separation that can be rated as ’optimal’.
Shortly before the actual contest, frequency management can be experienced ’live’. More than 20 TV teams from all over Europe will arrive in Copenhagen – and most of them will use RF wireless equipment to transmit ”their”
sound and pictures to the OB van. Of course this ”last-minute” wireless equipment has not yet been coordinated, and the TV teams are most likely to use frequencies which have been reserved for the Eurovision Song Contest.
The teams will therefore be informed of the ”forbidden” frequencies, and the RF situation will be continually monitored with RF analyzers before and during the contest. In the past, the odd camera transmitter was actually
made inoperative by security staff…
The Event
During the whole contest, all 64 RF wireless links will be in operation simultaneously. As performances alternate
quite quickly, artists and their equipment have been divided into three groups.
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| | Group 1 are the artists who are currently performing on stage.
| | Group 2 includes the participants which ”are next”. The audio crew will, for example, check whether the microphone and the IEM receiver are switched on.
| | Group 3 still has some time left until their performance. Where necessary, make-up experts will conceal miniature microphones in the artists’ hair. They have to take special care that the microphone does not get covered by make-up or hairspray. The microphone would become less sensitive to high frequencies, resulting in a dull sound which would be quite unlikely to help the artists in their musical career… Moreover, for hygienic reasons, each participant will be given a new ear-piece for the IEM receiver – if he or she doesn’t have a custom ear mold. |
In the hectic rush and tension before the artists go on stage there will always be last-minute ”trouble” which the expert must foresee:
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| | Cables get twisted and broken
| | The artist has unintentionally altered the settings on his or her bodypack transmitter or IEM receiver
| | Transmitter or receiver are switched off by accident. |
Very down-to-earth measures – such as covering all controls with tape – are the best protection against such faults. The experts also rely on Sennheiser’s 3000 and 5000 Series systems which feature computer remote
monitoring of the most important parameters including RF signal, audio signal and battery status. These values are continually checked for all three groups of artists/equipment.
Mission: Possible
”After all, this isn’t our first show,” says Klaus Willemsen, Sennheiser’s
”Red Adair” for RF projects. ”You see, we rehearse for more than a week and everything goes off without a hitch. But with a live show, nobody will care about
that – all that counts is the night of the broadcast. Usually, the greatest problems are not of a technical, but a human nature: during a live show, artists tend to get quite nervous. Almost everybody will forget what they learnt, because
the whole atmosphere is so different. And once the show has begun, we do not have any time for repairs or the like. All we can do is sit and wait until the three hours and twenty minutes are over…”
As the world's leading manufacturer of microphones, headphones and wireless transmission systems, the Sennheiser Group, which is
based in Wedemark near Hanover, Germany, registered a sales revenue of more than DM 380 million in the year 2000. The export share
is approx. 80%. Sennheiser has a total workforce of approx. 1,300 employees, 800 of them in Germany. Sennheiser is active world-wide
with subsidiaries in France, the UK, Belgium, the Netherlands, China, Singapore, Canada, Mexico and the USA, as well as independent
distributors in many other countries.
For further information, please contact:
Sennheiser electronic GmbH & Co. KG
Pressereferat • Edelgard Marquardt
Am Labor 1 • 30900 Wedemark
Fon: +49 (5130) 600-329
Fax: +49 (5130) 600-295
e-Mail: marquare@sennheiser.com
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