Duran Audio Germany was asked to supply an Intellivox system for the Parliament of Nordrhein-Westfalen in Düsseldorf. Nordrhein-Westfalen has 18 million inhabitants and is the most densely populated country of the federal republic of Germany, which it joined in 1949. Throughout history NRW has been the biggest and strongest industrial region of the federation, a position it still holds. Düsseldorf is the capital of NRW and seat of the ‘Landtag’, the Parliament of NRW which consists of 230 delegates. The present building was opened in 1988 and its unique skyline builds upon the idea that the architecture should reflect the function of the building; this is achieved by taking the circular form of the plenary hall as the basis for the rest of the buildings design.

The design stage
Berlin based consultancy Acoustic Design Ahnert, well known for developing the acoustical simulation package EASE,  were commissioned to design an intelligible and intelligent sound reinforcement system that would satisfy the needs of modern politics.

To obtain a clear picture of what the client required ADA conducted a series of interviews with the client and end users, from these interviews six important issues were identified; Multimedia techniques have become firmly embedded in contemporary decision-making process and any system would need to interface with these systems. Intelligibility is of key importance for every parliament sound system, as is source localisation and system reliability. The client also demanded a user friendly interface to control what was bound to become a very complex system.  Last but not least it was important that the system should be unobtrusive. This important input from the client lead to a well thought out and highly technical design.

A measurement survey of the reverberation times in the plenary hall indicated that the acoustics were quite mild so a distributed system in the ceiling of the plenary hall should achieve the required intelligibility. This system was to be controlled by a Nexus digital DSP which would be the firm basis for a reliable sound system with good source localisation. Audio routing is taken care of by the NEXUS system and a WinMic microphone conference handles the priority switching. AKG 647 microphones for are used the delegates and minister seats and Schoeps MK4 for the Presidium and the Chair positions.

A thorough survey of all the specific parliamentary procedures and protocols was undertaken by ADA to define the interruption rights. A simulation was then used as a tool to show the client the possibilities and advantages that a touch screen may offer. This would allow them to call upon a person to speak, deal with the overrule priorities while at the same time keeping track of the balance of speech and interruption time for SPD, CDU, FDP, Grüne and Landesregierung.

Presidents Touch Panel

Initial Implementation
Installation for the plenary hall and the three meeting rooms of the largest parliamentary fractions went out to tender and it was Siemens Gebäudetechnik West from Cologne won the tender. The most complex task was of course the installation in the plenary hall. Custom designed software had to be written to interface the three major elements: microphone control software, output matrix and touch panel software into one global, reliable and user friendly system.

Information is displayed on five 15” LCD touch panels in the presidium and a 21” panel in the technical room, all having different rights and system levels.
Delegates make a request to speak by pushing a button on their desk and the name and party of the delegate is shown on the display. The president can then decide when to allow that delegate to speak. The selected microphone address is transferred from WinMic to the Nexus digital matrix which in turn is then taking care of all the necessary routing from the specific microphone position to the corresponding loudspeakers in the ceiling, adjusting delay and levels for each output according to the direction the speech is coming from.
The ceiling of the round plenary hall is divided in 12 segments and there are three concentric rings in it with passive loudspeakers and lights. Two inner rings cover most of the plenum and the shadow area at the outer seats was taken care of by an under balcony system.  The third, most outer ring, serves the press and audience on the balcony.

Prof Anhert during the test setup

Test phase
During the initial tests it became apparent that the loudspeakers located in the ceiling weren’t giving a natural source localisation for the most important location in the plenum: the chair, from which 95% of all speeches are held. Speech intelligibility was sufficient, but could still use some improvement. So ADA was quick to organise a test set-up, with the help of Duran Audio Germany, using a pair of Intellivox-1b’s (now known as the DC 115), one placed each side of the chair.

The system needed to cover some 20 metres of the Plenary Hall but, for aesthetical reasons, they were restricted to using Intellivox-1bs (DC 115), with a typical throw of 10 metres. Thanks to the mild reverberation time this distance could easily be covered with the mid band frequencies (500-2kHz). It was noted that the high end of the frequency range could use an extra lift for the most distant seats. Fortunately, the under balcony ring of speakers could be used to supplement this part of the spectrum, using the appropriate delay with the chair as T0.

Final install of the Intellivox-1b's

Both loudspeakers were installed upside down in order to get the acoustical centre as high as possible. The beam was then aimed 5 degrees upwards to match the incline of the audience area. Some subjective testing then took place using male and female speakers speaking from the chair position; this was judged by a group of listeners from different positions within the plenum. Everybody involved was impressed with the results. So that only left the issue of the interior design. The front grill material was selected and a cabinet maker was asked to integrate the Intellivox into the chair. After he finished work the final beam and EQ settings of the Intellivox were programmed and the some final adjustments were made to the Nexus output matrix: timing, levels and EQ for the under balcony ring. The final results exceeded those during test set-up

Intellivox-1b infills for the ministers

Fills
Since the presidium was covered by very small loudspeakers mounted in the desk in front of every seat, the only seats that still required some attention were those that were not in line of sight of the Intellivox. The results at these positions were quite unsatisfactory.

More specifically, these were the minister seats and the clerks desk; located to the left and right of the chair. Two Intellivox-1b’s (DC 115) were used as fills to solve this problem. The units were housed within a very elegant enclosure and carefully set-up to compliment the main Intellivox-1b’s located either side of the chair.

The first parliament session proved ADA right in selecting Intellivox and the DDC technique for such an important project

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