Introduction
Thanks to the new Public Address system from Tyco Integrated Systems, those using the Dartford Tunnel, one of the busiest river crossings in Europe, can now be confident that they will be kept clearly informed about traffic situations, accidents and emergency evacuation procedures via high quality voice announcements.
The new system, designed to provide voice announcements in confined spaces, utilises more than two hundred specialist, low profile loudspeakers to achieve sound levels in excess of 100 dB across all six individually addressable zones of each tunnel bore. Featuring an extremely narrow sound opening, each loudspeaker has been designed to eliminate reverberation problems so often experienced in confined spaces.
Audio and data is transmitted to two ‘vent rooms’ via the existing Fibre Optic transmission system, which is then subsequently fed to zone switching units feeding amplifiers and thus powering the individual speakers. To ensure very high reliability and fault tolerance with 50% redundancy each speaker can be driven from either vent room.
Passing all intelligibility tests for drivers both inside and out of vehicles, the system has been designed to allow for expansion and the addition of automatic messaging technology
