14.05.09

Glittering delights

AUTHOR: Inavate
Inside the main hall the glass ceiling makes for interesting acoustics.

Chris Fitzsimmons reports on a technological face-lift for the historic Federal Palace in Berne, Switzerland. Installer Kilchenmann AG, under project manager Urs Hirsbrunner, was engaged to fulfil a design concept produced by consultant WSDG’s Basel office.

Switzerland’s Federal palace is a hundred-year-old edifice that has remained largely untouched since it’s construction at the start of the 20th century. However, following a five-year period of renovation, its classic sandstone façade now conceals building services and technology facilities worthy of a third millennium parliament building.

The awarding authority, Bundesamt fur Bauten und Logistik (lit. Federal office for buildings and logistics) appointed Aebi & Vincent Architekten AG with a mandate to integrate modern technology within a faithful restoration of the original building.

WSDG were then brought on board, under the leadership of Dirk Noy, in the companies Basel office. “The first contact we had was about four years,” explained Noy. “It was an enquiry about a study of the existing systems – an evaluation to see what the existing systems can still do. Their first idea was to re-use that system, and maybe modify some minor elements.”

The systems in this case refer to the sound reinforcement system in the National Council Hall, which is the main debating space of the Federal Palace, and also audio visual systems located in the numerous committee and conference rooms elsewhere in the building.

“The entire building was in a state of reconstruction for about two years, everything from HVAC systems to washrooms was being upgraded, and this presented an opportunity to redo the electrotechnical systems too, with the wiring redone at the same time,” he continued.

“We were then assigned to study the electro-acoustics of the main space, and using auralisation techniques were able to convey very dramatically our design intent to the client. He initially wasn’t sure it was worth all the effort replacing everything, but we showed him what would be possible using current technologies and that really clinched the deal. Even though we only used headphones, and not an advance, we were still able to give a good before and after impression.”

Because of the historic nature of the building, WSDG were severely limited in what they could do physically to alter the acoustics of the spaces. In the National Council Hall there is a huge glass skylight, and they proposed covering this with a transparent absorber. However this idea was rejected by the conservation authorities. Eventually the only acoustic treatments were some absorbent coverings to the front of the balconies.

The legacy system up for replacement was a centrally hung, horn loaded solution. “Not a pretty sight,” chuckled Noy. “The TV people really hated it because they couldn’t shoot from the balconies. However, for a fifteen-year-old system it didn’t sound too bad, as you can see from our STI histogram (see diagram). The old system had a mode STI of about 0.52 and the new one improves that up to around the 06.3 mark. That’s a nice improvement.”

The replacement system designed by WSDG uses the directivity control provided by line array technology. Two hangs of Nexo’s GEO 8 enclosures are located on either side of the centrepiece mural and driven by Lab.Gruppen C-Series amplifiers.

“The top element of each array covers the very back seats of the chamber, and the lower element is aimed carefully so that is doesn’t hit the microphones in the chairpersons’ positions. To provide coverage to those positions, we instead installed a kind of stage monitor arrangement on each desk. We used custom-built Stoll Audio Picoline speakers, also powered by Lab.Gruppen amps. They are only about 1” square, really discrete.”

WDSG also used the same, very discrete, speakers to provide sound reinforcement to the balcony areas. Opting to retain the existing Schoeps cardioid microphones, and custom built mixing solution, the consultant added some additional feedback elimination in the shape of a Bosch Plena frequency shifter. Additional DSP and audio distribution is performed by BSS Soundweb processors.

“All the DSP and feedback elimination is behind the scenes and automatic. The custom mixer we kept because during a session control is manual and the staff are already familiar with it. It was completely scratch built by a Swiss electronics company. The microphones will probably be good for another hundred years, so there was no need to replace them at all!”

Outside of the National Council Hall, Kilchenmann also installed audiovisual equipment in five conference rooms. The largest of these, known as room 301 is located in the roof space of the palace and is blessed with an amazing stained glass back wall. It caters for around 100 delegates including the chairman.

Here, from an acoustic perspective there is a lot of glass to deal with. Not only is there the impressive image at the back, but also windows on each side, which hide the translation and conference control booths. For this reason WSDG specified Duran Audio Intellivox DC-180 units to ensure minimal reflected sound.

The inclusion of a flush-mounted AKG CS2 conference solution, with its own loudspeakers, and also transcription points for secretaries increased the complexity of the system in room 301 and the other conference spaces.

The recording of meetings was one of the most important functions of the room as Dirk Noy explained: “They come into the meeting with a laptop, which they plug in at a dedicated seat. Everyone has the same laptop and software, and as a backup there is also a Marantz PMD 560 CF recorder. Both units record at the same time and there is even a UPS for each. If everything else fails the reporting must not, this was made very clear to us by the client.”

Distribution of audio within the room was carried out over a Cobranet network, using Biamp’s AudiaFLEX platform. As part of this Biamp EXPI and EXPO mini expanders were located around the room providing endpoints for the translation solution. Language options available from the Beyerdynamic SIS 120 units include French, German, Italian and a reserve channel.

A trio of Symetrix ZoneMix 760 units cover DSP for feedback elimination and an audio mix-down for the recording units. The video presentation system centres around a Sony VPL-FH300L high definition projector. This was selected due to its near silent performance and projects a VGA feed taken from an Extron Cross 128 Ultra matrix. Sources for the projector include a TV tuner, Marantz DVD player, room camera, a Wolfvision Visualiser and a Sony multimedia PC. All of these are displayed on a motorised HKS Congress screen.

For overall media control, Kilchenmann have employed AMX’s Netlinx system. A NI4100 system controller sits in the main rack, governing everything from video source switching to the conference system.

The conference system itself can operate in two modes. For smaller sessions, it can be set to operate in a simple, self-controlled mode where delegates use an AMX NXT touch panel to control proceedings. In normal use the whole system is managed by an operator in one of the translation and control booths.

In the other four conference rooms (each catering for 60 delegate), a similar but less complex system is installed. There is no translation functionality, and as they are smaller spaces sound reinforcement comes from Tannoy loudspeakers located behind the Projecta Elpro screens (fixed). The projection solution is projectiondesign F30s in these cases, which are fed from a smaller Extron Crosspoint 84 matrix switcher.

Of note through out these conference and committee rooms is the need for privacy. There is no hard wiring between any of the rooms, to ensure there is no possibility of eaves dropping on private political sessions. This was a legal requirement. It is for this reason that the wireless distribution in room 301 was done using Sennheiser infrared as opposed to a radio solution – there is no possibility of the signal bleeding outside the meeting room and being intercepted.

Aside from the chance to upgrade the audio and media systems in the meeting spaces, the parliament also took the renovation as an opportunity to improve the general facilities. The construction of a new visitor’s entrance allowed them to separate parliamentarians from members of the public and press for security purposes, but also necessitated the implementation of a sitewide digital signage and information solution. Kilchenmann also won the contract to provide the system at the back end of 2008.

Andre Fluri was responsible for running this part of the project and described the solution he installed: “We’re not using a traditional signage product, instead we have a DVI distribution system running through a PureLink 36x36 DVI Matrix. There are a total of 16 play out PCs as sources, running bespoke software, and we have a total of 29 displays located throughout the site. These are 55” LG/Philips LCDs in custom enclosures that we designed and built ourselves.”

To extend the DVI signals through floors and corridors, Kilchenmann employed a hybrid Fibre and Cat-5 solution using Magenta Infinea Rx / Tx units to carry the signal between floors over fibre, and Cat-5 once at the appropriate level.

The reason they opted for a DVI / PC solution was for flexibility of content. The parliament can show simple schedule information, or welcome messages but for special events full HD video and accompanying audio can also be sent to any of the displays in the network. The bespoke enclosures were part of the requirement from the architects for an attractive solution. They contain custom-designed convection cooling, power electronics and a very small number of fans to keep them quiet.

In toto, the renovation project has gone on for almost 5 years, Kilchenmann began work in 2007 on the conference rooms and then installed the new National Council Hall system in 2008. The digital signage system was commissioned in March 2009. Both Dirk Noy and Andre Fluri agree that the most challenging aspect of the project was integrating the new systems into the fabric of an old building.

“The cabling was quite difficult, getting it to our displays through the floor etc. Fortunately the electrical contractor did most of that,” said Fluri.

“We didn’t want to hide everything,” added Noy. “We wanted it to be part of the architecture. There was a lot of dialogue between the integrator and the architect. The technology itself was not too challenging, but we only had a total period of 5-months for the main hall for example. So there were sandwiches of two months of installation then one month of operation. Clearly they couldn’t shut down the whole parliament, so at the end of each of those two-month work periods, we had to have a completely operating system in place. We therefore left as much of the original system in as long as possible.”

“Over all we are very happy,” concluded Fluri. “All the feedback we have received from the customer is good.”