Symetrix for Paris railway station install14 June 2011
Gare de l’Est – one of the oldest rain stations in Paris – has been equipped with a Symetrix Jupiter 4 processor as part of a new sound system in the ticket sales area.
Public address integrator specialist Sound Directions was given the responsibility of delivering information and advertising messages to customers in this part of the complex. The installation was completed by Audio Visuel Zoom.
To ensure precise, highly directed audio, Sound Directions systems specialist Christophe Palluat de Besset selected MystSystems PAN64 ceiling-mounted loudspeakers. The PAN64 broadcasts in a square of 64-centimeters at a constant level for up to fifteen meters, with a steep drop-off outside that beam width. A modest rack of MystSystems B17 100-volt amplifiers provides power.
“The main challenge at Gare de l’Est is the huge variability in the number of customers at different times of the day and thus the huge variability in ambient noise,” said Palluat. “It was evident that we had three options. We could make it loud enough to be heard in crowded conditions, but then we would blow people away at the less busy times. We could make it appropriately loud for those less busy times, but then people would miss the information when it was crowded. The ideal solution was to implement an automatic gain control that would adjust to match the ambient noise.”
Factors including the Jupiter’s competitive pricing and long history of providing automatic gain control (AGC) in transport facilities led Palluat to select the Jupiter 4, which at Gare de l’Est provides not just AGC, but the rest of the system’s processing requirements as well. Three sensor microphones located at strategic locations near the SNCF desk monitor ambient noise for use in the Jupiter’s AGC algorithm.
Modelled after smartphone technology, the Jupiter hardware can take on a multitude of ‘processing personalities’ through a host of apps that can be downloaded from the Symetrix.co website. For Gare de l’Est, Palluat used the ‘Gain Sharing Automixer #1’ app.
In addition to the AGC functionality, he used parametric equalization to reduce frequencies near 150 Hz, thereby increasing directivity, and boosting frequencies near 5000 Hz to improve intelligibility.