As part of a national programme of investment in infrastructure by Network Rail, who operate and are responsible for Glasgow Central, a new public address system was required as part of a wider renovation of this important transport hub. Previously, the station had a long-standing problem with intelligibility due to the cavernous nature of the iconic structure and its architecture, with expansive reflective floor surfaces, sandstone walls and a glass roof all contributing to a very lengthy reverberation time.
To handle the extensive audio upgrade, Network Rail and main contractor Babcock brought in respected UK-based sound and communications company TG Baker, having developed a strong working relationship with them over previous rail network projects. After careful consideration and design testing, TG Baker's elected to proceed with the optimal solution comprising of QFlex, Tannoy's award-winning digital beam steering loudspeaker range.
Brian Andrew, who heads up the Railway Division for TG Baker, said, "Glasgow Central is a famous Victorian structure that is protected by The National Trust for Scotland, which in itself presented a whole set of architectural limitations. As well as that, the station had a problem with intelligibility of announcements, as the reverberation time was in the region of 6 seconds.
"Deploying conventional speakers would have meant a low direct to reverberant ratio, adversely impacting on intelligibility. With such a harsh acoustic environment and protected architecture, acoustic treatment of the space would have proven to be prohibitively expensive, so in the end the whole project required a cutting-edge technology solution, and digital beam steering was the perfect answer. In most cases digital beam steering technology is the only effective way of achieving the required levels of speech intelligibility in large reverberant spaces."
Network Rail and Babcock were looking at a number of loudspeaker technology options, when TG Baker put forward proposals using Tannoy's QFlex.
Continued Andrew, "Apart from a significant cost saving to the customer, another good reason for using QFlex over some of the alternative steerable options on the market is that most other products have a fixed mounting height. But in Glasgow Central, the National Trust for Scotland dictated the height of the speakers, where they were to be positioned, and also the colours of them. Tannoy was able to offer combinations of different custom colours in order to blend with the surroundings and mimic what was there before, and the adaptability of QFlex meant they could be mounted where required, without compromising on coverage."
The installation includes 29 QFlex 48s, eight QFlex 32s and ten QFlex 16s, all in varying customised colours to match the existing architectural scheme. Comprehensive system overview and diagnostics is provided courtesy of six Sentinel SM1 system monitors, which sit on the VNET network and ensure system-wide integrity and provide alerts in the event of any fault condition, eliminating the need for a PC to be constantly connected to the network. This is essential to the system's compliance as a mass-notification and emergency paging system, providing reporting solution that meets and exceeds all worldwide legislative and safety standards.
(Jim Evans)
