Buttenheim, 08^th of October 2015: Salzbrenner Stagetec Audio Video Mediensysteme GmbH, the systems integrator of Salzbrenner Stagetec Mediagroup, played an important part in updating the audio and sound reinforcement system of the Turkish Parliament (Grand National Assembly) in Ankara. Supervised by Professor Ahnert of the Berlin-based company Acoustic Design Ahnert (ADA), two Mediagroup teams of two spent the summer of 2014 in Ankara to equip the parliament with a directional sound reinforcement system. With the parliament’s summer recess postponed several times, the Mediagroup team was glad that their collaboration with engineering company Atempo in Ankara, which installed the cable runs, d&b power amplifiers and speaker clusters, went smoothly despite the tight schedule.

Salzbrenner Stagetec Audio Video Mediensysteme GmbH has implemented designs by Acoustic Design Ahnert, which was in charge of the Ankara project, on numerous occasions, such as for the German House of Representatives in Berlin and the State Parliament in Düsseldorf. Both venues were equipped with a directional sound reinforcement system based on the Nexus Gain/Delay Matrix. While directional sound reinforcement is not new, only a few houses of parliament currently boast such an advanced system. In Ankara, the team installed and connected a Polaris Touch mixing console, an additional Nexus Base Station and a C.A.S. 50600 media control system. One of its functions is to monitor and report the system status to the operator in the control room.

Directional Sound Reinforcement Based on a Zone System

In Ankara, the Grand National Assembly is divided into seven floor zones: three for the podium including the president, the speaker desk, the commission and the ministers, and four for the delegates. “This makes it easier for the delegates to follow debates because they are now able to determine the origin of a question from the floor area,” as Jochen Schulz, the systems integrator’s technical coordinator for the Ankara project, explains.

All in all, the Nexus system’s Level/Delay matrix handles 56 audio output channels that feed dedicated power amplifiers. Connecting the channels to their respective power amplifiers and verifying all connections is a rather time-consuming exercise even if there are no cable mix-ups.

Calibrating this enormous amount of channels and speakers is a specialist job and was performed by Professor Ahnert, who is the first to admit that using measurement microphones only gets you so far; experience, expert ears, and the capability to compromise reasonably are no less important. Based on the concept developed by Enno Finder (ADA) and Professor Ahnert’s instructions, the Mediagroup team optimized the frequency response and programmed the Level/Delay matrix, setting the correct levels and delays for every single speaker, depending on its physical location, individually for each of the 7 source zones. This way, the sound is loudest and first perceived from the approximate area of the microphone that a representative uses to ask a question or make a comment. Avoiding phase issues and intelligibility problems becomes a real challenge when using 56 speakers spread all over the hall. Nevertheless, it took Jochen Schulz only two days to get approval from both Professor Ahnert and the parliament’s authorities.

Touch, Control, Hands-On

The Atempo team installed and connected an intuitive Polaris Touch mixing console by the Mediagroup brand Salzbrenner. Due to long distances within the parliament building two Nexus Base Devices were used to provide all the functions requested by the client — one in the control room, the other under the roof next to the power amplifiers, connected via fibre-optic cabling to keep the cost down and to enable error detection in the control room. The Nexus system was connected to the d&b network to provide connectivity and remote control functionality of the power amplifiers.

Status control and error monitoring of the power amplifiers and speakers is handled by a management routine running inside the C.A.S. 50600 Media Control system. This system is also connected to programmable eight-key remote panels, which allow guides to access the sound system’s basic functions from outside the control room. The overall system provides three modes: off (all power amplifiers on standby), visitor mode (access to basic functions via remote panels) and assembly mode (operated from the control room).

Once the system was up and running, Jochen Schulz and Dominik Stepanek of Salzbrenner Stagetec Audio Video Mediensysteme GmbH returned to Ankara in October 2014 to provide hands-on training for the 10-strong technical crew. After explaining both the general system overview and each device in detail, another day was spent team working with Enno Finder from ADA to simulate a number of errors, providing invaluable troubleshooting tips for the parliament staff. Stepanek, the Polaris Touch Product Manager, demonstrated all Polaris-related subjects during the comprehensive training sessions, and once again confirmed that “these sessions not only provide operators with the vital knowhow to use the system in the future—they also provide us with invaluable practical feedback on our products.”