Sound Technology Ltd, the Harman Professional distributor in the UK and ROI, are pleased to announce a major installation by TG Baker (Sound) Ltd of a performance networked audio system incorporating JBL loudspeakers, Crown amplifiers and BSS Soundweb network processing at the Aviva Stadium in Dublin.
The new stadium, which opened at Lansdowne Road, Dublin this summer, at a cost of €410 million, provides Ireland’s international rugby and soccer teams with a new home. A joint venture between the Irish Rugby Football Union (IRFU) and the Football Association of Ireland (FAI), funding of €191 million was provided by the Government.
Constructed by Sisk, and offering covered seating for 50,000, the stadium consists of a continuous waveform shaped stand enclosing all four sides of the ground. The South, East and West stands provide five tiers (three seating and two at corporate box level) while the North stand comprises just a single low level seating tier (reflecting its proximity to the residential properties at that end of the ground).
The challenge of supplying, installing and commissioning a fully-compliant public address voice alarm (PAVA) system for the stadium (including a performance system for the bowl seating and 100V audio for all other areas), fell to Glasgow-based TG Baker (Sound) Ltd, who had previously installed and commissioned a large-scale PAVA system for nearby Croke Park. The specification required a series of fully-redundant digital audio networks (with isolated UPS) to ensure continuity.
“We believe that the major factors for being awarded the contract were the number of stadiums we have in our portfolio and a proven track record for supplying sound systems of this nature on time and in a cost effective manner,” stated TG Baker system designer, Tony Mott. But first his design proposal had to be approved by independent consultants, Peter Mapp and Eddie Thomas, representing the client.
The contractors turned to the Harman Professional catalogue for their loudspeaker, amplification and network control/distribution requirements. A JBL and Crown solution was detailed exclusively for the bowl, while a sophisticated BSS Soundweb London digital architecture, in combination with a BLU-Link fibre backbone, was commissioned to handle signal routing and audio processing throughout the stadium. All components were supplied by Sound Technology Ltd with support and assistance provided for the project by the company’s Project Team.
To enumerate the scale of the design, the installation comprises 26 x 42U racks (25 for the main PAVA system and one for the Press Conference area), 118 PAVA zones, 59 paging zones and 365 loudspeaker circuits.
The system has an audio matrix of 172 inputs and 468 outputs, and due to the design topology there is currently 25% spare capacity for future I/O expansion.
The Public Address
TG Baker project manager Tony Mott optimised the stadium design using EASE acoustic modelling software while Vanguardia outlined the acoustic performance requirements.
To fulfill the design, Mott turned to JBL’s weather-coated Precision Directivity™ (PD) line of speakers, and using custom bracketry, different horn orientation and pattern control he managed to achieve uniform distribution to virtually every seat in the house — from the tribunes down to the pitch.
Explaining the choice of loudspeaker, the designer stated, “During the tender stage we considered a number of loudspeaker options. However, having successfully used the PD series on other stadium projects we knew we could demonstrate to the client that the proposed sound system would meet the performance requirements detailed in the specification.”
The stand design is thus based around a total of 105 JBL PD Series loudspeakers in 56 cluster positions.
With only one tier to worry about on the North stand, coverage was relatively easy to achieve with a combination of PD5200 and PD5300 series loudspeakers installed on the edge of the roof. However, on the other three stands TG Baker used a horseshoe shape of high impact mid-high PD743 loudspeakers to evenly cover the longest throw from the gantry to the lower tier, a combination of PD5200/95 and PD5200/64 loudspeakers for upper tier coverage, and a ring of PD5125’s providing the LF. Finally, five AM6200/64 loudspeakers from the JBL Application Engineered (AE) Series provide additional pitch coverage.
The sound system’s primary role is to deliver a high speech transmission index (STI) — and during commissioning in an empty stadium bowl STI's of between 0.55 and 0.65 were measured. It was designed to achieve a broadband SPL of >105dB and speech SPL of >101dB.
Powering the loudspeakers from the 26 rack positions are multiple Crown CTs 3000 i-Tech 4000 amplifiers, fitted with PIP-USP3 modules. Predominantly each Crown amplifier channel feeds two loudspeaker drivers. “We use the PIP-USP3 modules specifically because they support 20kHz pilot tone monitoring of the loudspeaker lines and because we can confirm the full loudspeaker impedance using the built in sweep functionality,” says Tony Mott.
The design also ensures that there is no single point of failure, with both an A and B position on each stand, providing full redundancy — backed up by UPS power conditioning and mains support.
Control & Network
A sophisticated Soundweb London BLU DSP topology handles all audio distribution, processing and routing control for both the bowl and voice alarm systems.
Each network is wired in a complete ring starting and ending at the server rack. Audio distribution is via the BLU-Link, and any break in the ring automatically broadcasts the audio in both clockwise and anti-clockwise directions. TG Baker monitors each BLU-Link input port, and any failure that occurs is reported to the fault monitoring system.
One of the key advantages of the Soundweb architecture was the ability to use the BSS BLU-Link solution; this is a 256-channel, fault-tolerant bus which can use standard, inexpensive Cat6 cabling (linking BLU-Link compatible devices over a distance of 100 metres) but via 1000BASE-T/SX/LX fibre media converters these distances can be increased substantially.
With 25 PAVA rack locations it was easier to use the BLU-Link with a single bidirectional audio bus that supported 256 channels with low latency than having a complicated CobraNet topology, explained Mott. “Further to that hardware costs were reduced because there was no CobraNet licensing and programming costs were reduced due to the simplicity of the audio bus structure.”
Providing the processing engines are Soundweb BLU-160 devices in each rack, with configurable I/O’s — which offer a huge amount of DSP capacity. All loudspeaker processing such as bandpass filters, delay and equalization, is handled by the Soundweb BLU devices and adjusted in Soundweb London Architect. Audio feeds are sent from the BLU-160s to the Crown amplifiers.
TG Baker senior engineer Scott McLucas handled all the BSS programming, using London Architect. He stated, “Soundweb was the obvious choice for this installation — the graphic interface sets everything out in front of you and helps you visualise the scenario as you design it. The whole set-up is just so simple.”
The voice alarm system functions under the command of a priority / cascade system — touch-screen panels have been included for the main paging consoles with a series of emergency mics and pre-recorded evacuation messages.
Up in the DJ control booth the pitch side pre-match and half-time entertainment is mixed on a 24-channel Soundcraft analogue GB4-24, while a BSS Soundweb London BLU-10 programmable wall remote provides local source select, volume control options and generic presets for match day scenarios.
During handover to the client TG Baker provided four separate training sessions to cover all eventualities.
The company can rest in the knowledge that they have designed a fully-redundant, remotely-monitored sound system. A VPN link between their Glasgow office and the stadium IT network enables remote interrogation and control of the PAVA server.
The installation complies with BS 7827:1996 The Code of Practice for the Designing, Specifying, Maintaining and Operating Sound Systems at Sports Stadia; IS EN 60849:1998 Sound Systems for Emergency Purposes and BS5839 Parts 1, 4 and 8.
Summing up, Tony Mott states, “It was a dedicated team effort that enabled us to complete the project on time. Ultimately we have accomplished what we set out to achieve and everybody is delighted with the audibility and intelligibility of the system.”
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