05/2007

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As Clear as Crystal
Leading edge Convention centre with NEXUS
Changing for the better: Vietnam’s vibrant capital Hanoi is now
a bustling metropolis with many attractions and a new highlight.
In an extensive parkland setting the National Convention Centre, NCC, opened its
doors in 2006. It is by far the largest and most
modern convention centre of its kind in the country. For superb sound and clear speech
the National Convention Centre relies
on an optical network with many satellites
Long, polished limos glide past, helicopters circle overhead and
vigilant security guards are everywhere. The atmosphere is electric.
High ranking visitors, among them Vladimir Putin and George W.
Bush, have assembled at the NCC for the APEC Summit, held in
Vietnam for the first time in November 2006. This was an event of
enormous importance for Vietnam, which had recently received the
immensely significant confirmation of its admission to the World
Trade Organisation. Therefore, hosting the Summit offered a unique
opportunity to showcase the country’s rapidly growing economy to
the entire world.

Lofty Aspirations – Not Only for Audio
Vietnam has set itself ambitious goals. In 2010 the capital, Hanoi, is to
achieve the status of a modern industrialised town. This vision is being
pursued vigorously and using high-tech means. Therefore, it comes as
no surprise that the newly built NCC was designed and constructed
according to the most demanding international standards and with
the participation of many foreign companies. The architects, the site
managers, air-conditioning suppliers and the construction engineers
came from Germany and with STAGETEC also the digital audio
networking supplier.
The specification required the installation of an integrated and reliable
system providing not only the necessary flexibility but also outstanding
audio quality and a high degree of redundancy. The NEXUS with its
flexible audio-network topology is perfectly suited to fulfilling these
requirements.
A Demanding Network
The classical virtues of the NEXUS make it the ideal solution for a
convention-centre environment. In the NEXUS system, communication
between units is based entirely on optical fibres. Therefore a NEXUS
network simply eliminates the problems inherent with copper wiring.
For example, interference or signal deterioration on long cable runs.
The modular architecture of the optical network is particularly
installation friendly; allowing for significant manpower savings when
compared with copper-based speaker and microphone networks.
At the NCC, just four thin fibres handle the duplex transmission of
128 audio channels including control data and even provide cabling
redundancy!
Another decisive argument for the NEXUS was the converters on the
TrueMatch boards, which offer 28-bit resolution and a dynamic range
of 153 dB for unsurpassed audio quality. Altogether a total of 64
XMAD TrueMatch microphone-input boards are available at the NCC.
The Heart of the System
Each of the most important rooms such as the Plenary Hall, the
Banqueting Hall, the International Conference Room and other
meeting rooms is equipped with a dedicated NEXUS Base Device.
This provides convenient connectivity to the audio network. The
distributed Base Device locations enable, for example, audio signals
produced on the Plenary Hall stage to be fed locally into the NEXUS
and routed over a MADI interface to a third-party console for mix
down.
NEXUS also feeds the sound-reinforcement systems, so it acts as the
core of the entire audio system. Moreover, the NEXUS DSP modules
also handle tasks such as summing, equalising, delay, and gain control
in each sound reinforcement area of the NCC. In order to be able to
react even more flexibly to the specific requirements of an event, the
NCC network also includes two extra portable NEXUS racks.
In total, the NCC digital audio network comprises around 700 sources
and 700 destinations that are made available by 13 Base Devices and
two NEXUS STAR routers. The installation is based on a star topology,
with the two interlinked NEXUS STARs at its heart and the Base
Devices acting as satellites.

Network Security
For redundancy and reliability, each Base Device includes two opticalinterface
boards that run signals in parallel to the NEXUS STARs in the
main control room. If an optical line fails, the signals can be routed
via the second connection. The probability of both optical cables or
both interface boards failing at the same time is negligible. Each Base
Device and STAR is also equipped with a redundant power supply. All
of this avoids any single point of failure and makes the overall audio
network at the NCC very secure.
The NEXUS internal monitoring program provides still greater security.
When a component on the network fails, a notification is submitted
immediately. Incidentally, these notifications, as well as all other
messages and prompts on the NCC NEXUS, are displayed in the local
characters and language, Vietnamese. This is a small but very useful
detail, making it easier for local operators to use the new technology.
A Flexible Solution
The NCC NEXUS system is administered and controlled by a computer
located in the main machine room. However, in such a large and
extensive installation, it may be more convenient to access the audio
network locally, that is, inside a meeting hall. This applies particularly
to the metering window. Whenever signals are being modified the
metering window should be visible. On NEXUS networks, it is possible
to hook up a PC running the NEXUS control software to any node
on the network, even if there are other computers already active in
the system. At the NCC, this feature is exploited and now up to four
extra NEXUS control computers can be put online in the various halls.
To avoid unauthorised access, these NEXUS satellites are password
protected with restricted user rights. This highly flexible solution is
ideal, especially when considering the fact that the NCC is used for
such a wide variety of applications.
All’s Well That Ends Well
The final construction stages of big projects like the NCC are often
the most critical, due to the immense time pressure. The companies
involved have to compete to complete their respective installations. A
dusty and dirty construction site is certainly not an ideal environment
for the installation and testing of optical fibres! However, all the audio
network lines were carefully cleaned and put through their paces
before commissioning.
After all, the APEC Summit, which took place at the same time as
the formal opening of the convention centre, had to go off without
any hitches. In the end, the acid test was passed. Thanks to the ideal
technology for the job and excellent STAGETEC audio fidelity, the
Summit in the ‘City Between the Rivers’ was a complete success.

The NCC in Brief
In an overall area of 60,000 m², the NCC in Hanoi accommodates
a conference room with 3,500 seats, a 1,000-seat banqueting hall,
two conference rooms for high profile visitors, and several smaller
conference rooms with 100 to 200 seats each. Apart from meeting
rooms there are facilities for seminars, working and exhibition spaces,
a press centre, and other service facilities.
Meinhard von Gerkan and Nikolaus Goetze from Hamburg based
gmp architects created an overall complex embedded into rambling
parkland with thematic and symbolic allusions to Vietnamese tradition
and culture. Several hotels and a museum complete this architectural
ensemble.
The evocative Convention Centre roof is modelled on a wave and
accompanies the visitor on their way through the foyer. Access via the
helipad on the rooftop is however, reserved for prominent guests. |