Turf Moor Stadium, Burnley F.C.

With their welcome promotion to Football’s elite Premier League, Burnley FC have treated supporters at their 22,000-capacity Turf Moor stadium to a fully integrated digital network public address system that is highly-intelligible and PA/VA compliant.

Having spent 33 years outside the top echelons it was perhaps fitting that The Clarets’ first clash would be with reigning champions Manchester United. Part of the client’s brief was to effect a 12th man home advantage...and the PA received a rousing reception and a famous victory was recorded.

Acoustic consultants AMS Acoustics, had already any implemented an earlier first phase upgrade last season to bring three stands into VA compliance. During the course of this exercise the capture of a full range of measurements was required and the resultant data, after analysis, was used as the cornerstone for an entirely new design the following year.

During the short closed season AMS returned with ETA Sound to implant a complete Harman Pro solution, using a fibre-based signal network that would extend to the three main stands — the North (James Hargreaves) stand, the East (Jimmy McIlroy) stand and South (Bob Lord) stand.

The West (David Fishwick) stand is under review with the expectation that it will be replaced; this will in effect form part of a Phase 3 system enhancement (along with the back-of-house areas) for which cabling has already been implemented.

Tasked with supplying a voice alarm-compliant system, with high STI (Speech Transmission Index) AMS Acoustics’ project designer Helen Goddard made her product selection with care. For she sensed that the voice evacuation system could double up to meet on-pitch entertainment requirements.

Reverberation (RT) and audio communication times within the stadium (along with certain modelling data of the stands), had already been plotted by AMS Acoustics, who believed that having worked successfully with the JBL AE loudspeakers in the past, they would again meet the remit.

The company needed to achieve peak level in an emergency scenario, related to crowd noise. "We knew the system would have to achieve a maximum of 102-105dB(A) and this meant we needed to use loudspeakers that would be able to achieve these kind of levels without going into compression."

First the JBL loudspeakers were set a number of challenges — including a performance evaluation in AMS Acoustics’ anechoic chamber, even to the point of a destruction test. This was supported by Sound Technology, the Harman Pro distributors, who provided all the necessary back-up.

The acousticians then set about designing the control, signal path and zoning matrix, opting for an integrated Harman Pro package based on system optimisation and cost-efficiency. "As the budget was quite tight this was the logical way to go," stated Goddard.

Crown CTs amplifiers, fitted PIP-USP3 speaker processing units, BSS Audio Soundweb London DSP devices, with BLU-link, running on a fibre backbone — and independent HP ProCurve network switches across all rack locations — form the system architecture. In this fully-redundant design, UPS systems provide all the power conditioning and mains support in the event of a power failure.

The installation was also notable for the advanced DSP programming skills of ID Networks’ Martin Barbour, using the attributes of Harman Pro’s new London Architect v2.06 and System Architect v2.00 software — the latter being its first use anywhere in the world. "Given that this was a fast fit job it saved me huge amounts of time," he said.

LOUDSPEAKERS AND COVERAGE

It was the task of Eddie Thomas’s ETA Sound to convert the CATT-Acoustic stadium model, created by AMS Acoustics’ Lorenzo Morales, into reality. To achieve this, he assembled the same design team that had been used so successfully on the O2 Arena build project.

He also worked closely with Tom Williams, Sound Technology’s acoustician. In fact the latter had been closely involved from the outset of the project — taking part in the initial concept discussions with AMS Acoustics, supporting the equipment testing and measurement procedures, setting up the load monitoring — and finally assisting with system commissioning.

In total 16 x AM6315/95 (90° x 50°) full range loudspeakers with rotatable horn and 12 x AM6200/95 mid-high have been used.

In the South Stand AM6315’s have been deployed, mounted horizontally to counteract sightline restrictions, with the horn rotated. Covering the East stand are three clusters, each with AM6315/95 in the vertical plane and AM6200/64 covering the lower raked seating (90°x 50°).

In the North stand there are five similar clusters of the same, with the AM6315/95 mounted at the top in the vertical plane, and AM6200/64 bolted under to cover the lower rake. An additional four AM6200/64s (60°x40°) are also suspended on the north stand, specifically to provide pitch coverage.

Eddie Thomas reports that the specially-commissioned mechanical bracketry had much to do with the evenness of coverage. "Working with the supply company and the structural engineer we devised a method for hanging 100 kg weights off the roof supports and getting the speakers to where we wanted them."

This was no easy feat — since the roof was inverted the contractors had to cut through the cladding to get to the supporting beams. All brackets were powder-coated battleship grey to match the loudspeakers.

DIGITAL NETWORK AND CONTROL

The entire system runs on a fibre based backbone with media convertors for the BLU-Link data and HP GBICS-LC providing fibre interfacing on the HP ProCurve switches. The fibre infrastructure provides one dual redundant Ethernet network as well as an independent ring for the BLU-Link audio transport.

Each of the three equipment rack locations features two HP ProCurves switches, two Soundweb London BLU-160 DSP’s and Socomec UPS in each room (as well as the two fibre converter interfaces for BLU-Link). Says Martin Barbour: "Two BLU-160s in each location gives us more than enough DSP — they are hugely powerful devices."

The network services a total of 23 PA zones although these are logically broken down into stands, concourses and turnstile areas. The Soundweb London devices are configured for a maximum of 72 outputs and between 24 inputs.

Barbour explains, "Originally this was to have been a CAT5 installation but when the client moved the rack locations this took us outside the Ethernet 100m range — so we suddenly had to rethink the networking aspect." Eddie Thomas’s team then designed and arranged a fibre network to be provided and installed within two weeks.

"Installing BLU-Link at this stage provides us with the audio routing headroom we need when the expansion works commence," he says. "The channel count and ease of use made it an obvious decision."

The voice alarm requirements are met by monitored message store devices — housed in independent rack rooms; these are continually monitored and available to any of the PA zones, automatically or manually. Every stand can be evacuated individually, or the entire venue in one operation. Alternatively, coded alerts can be sent to alert the ground staff.

The majority of London Architect’s Logic programming is dedicated to the graphical user interface and voice evacuation autonomy which is permanently monitored. This allows any of the evacuation messages or microphones to be routed to any of the PA zones, while in each rack location there are also local access mics as a final tier of security.

Each output has its own independent gains and EQ with three volume settings — low (dropping the system down to 85dB), match day level (which runs at 100dB) and the emergency max. level (of 102-105dBA).

THE NEW HARMAN PRO SOFTWARE

Martin Barbour says that running both the new London Architect v2.06 and System Architect v2.00 software offered huge advantages. A notable feature of the new Soundweb system designer is the Wire Tags feature. "This feature comes into its own with complex and vast DSP or Logic designs. It enables me to keep the design tidy, easy to follow, and when used in combination with Macros, easily expandable."

He had already been part of the Beta test team for System Architect v2.00 and was aware of its attributes.

"With the new workflow based design approach we can associate the amplifier channels with physical and logical areas within the venue. This allows the software to automatically create default control panels for each logical zone which would otherwise have had to be built manually.

"In terms of stability and performance, you don’t get any more pressure than a visit from Manchester United FC on your opening home game, with the World’s first System Architect v2.00 install! The system performed flawlessly and thanks to the time saving attributes of both software applications, we were able to fit the demands of the very tight deadlines."

SUMMING UP

Both Helen Goddard and Eddie Thomas are delighted with the integration and STI measurements. For Thomas it was about designing and building the racks, sourcing the custom built JBL cabinets and installing the entire system, from roof cables, network and containment, in just five weeks. He not only managed to achieve even coverage but also immediate plaudits for the PA’s output and intelligibility on national radio.

For Goddard and Morales it is the fact that all elements are fully compliant, meeting the safety requirements of BS5839 Part 8, BS-EN-60849 and the performance recommendations of BS7827.

The existing internal systems on the inner concourse can now be replaced in due course and the new system retro-fitted to the fibre backbone. Likewise, when the new stand comes up for development the sound system can also break into the existing fibre ring.

Helen Goddard is full of praise for ETA Sound’s achievements. "They have done an amazing job," she acknowledges. But for her the final icing on the cake was in converting the match day DJ’s heavily compressed programme material to high quality .wav files. "The tracks were sounding strange and we found we were losing the lows completely; the difference that removing the heavy compression is now making to the quality of the sound system is unbelievable."

Since ETA Sound had also provided high end digital mixer and radio microphone equipment, along with an IEM system, the re-formatting of the pre-recorded music used on match days was vital.