Touring the Sports Hub
Stadia bear more than a semblance to the countries of their birth as exemplified by Singapore. The Lion State was only eight years old when its National Stadium was inaugurated by the River Kallang in 1973 and at the time it more than satisfied the needs of the young country. National Day celebrations centred upon this landmark for the next three decades, whilst international artists such as Michael Jackson and Mariah Carey would sell out the 30,000 capacity venue in-between sporting events. But just as the city of Singapore around it dramatically rose over this period with increasingly modern and sleek grand designs, the outdoor stadium began to crumble in the equatorial heat and heavy rain. The government, therefore, decided to act and commissioned the creation of a bigger, multi-functional and green stadium, in which the audio design would play a starring role.
Seven long years passed following the curtain call on the old National Stadium and the inauguration of Singapore Sports Hub. The large fireworks display that lit up the night sky above the Stadium following the extinguishing of the flame in the cauldron on 30 June 2007 proved to be a false dawn however. Demolition work had been scheduled to commence a year later, but owing to the subsequent global financial crisis in addition to rising construction costs, the project was pushed back three years. A ground-breaking ceremony marking the arrival of bulldozers on 29 September 2010 marked the official end of the Grand Old Dame with the laying of new foundations six months later. At that point, the vision to create a 55,000-seat stadium complete with a movable, ultra-thin dome roof structure and innovative moving tier design that would accommodate various sporting and cultural events appeared a distant dream.
The Singapore Sports Hub is a 25-year Public-Private Partnership (PPP) agreement between Sport Singapore and Sports Hub Pte Ltd, making it one of the largest sporting infrastructure PPP projects in the world today. It made its ambitions clear by contracting both Arup and DP Architects to design and engineer a sustainable stadium within the 35 hectare space that would also incorporate entertainment and lifestyle hubs.
Arup’s appointment was made easier following its credentials earned whilst creating the Beijing National Stadium (Bird’s Nest), Allianz Arena in Munich and City of Manchester Stadium. As the longest established systems integrator in town, Electronics & Engineering Pte Ltd (E&E) has played a significant role in incorporating cutting edge A/V solutions within Singapore’s most noted landmarks. In recent years, its hall of fame has expanded with the Marina Bay Sands Resort, Star Performance Arts Centre and Gardens by the Bay.
Just as Singapore has matured and prospered, E&E has also grown from humble family roots. For managing director Ronald Goh, returning to the scene of his greatest ever triumph is another pinnacle moment in a distinguished career spanning five decades.
‘One of the most satisfying projects that I had ever accomplished in my career was designing and providing the sound system for a one night only performance in September 1984 of the New York Philharmonic Orchestra at the National Stadium,’ he recalls. ‘We were commissioned by CitiBank to provide the sound system for this once in a lifetime performance. However, the purist and critics said that the National Stadium was a poor choice of venue for such a performance because of its size and echo problems. That put additional pressure on me and I had to put in extra efforts to make extra sure that I got everything right.’ Inevitably, Mr Goh more than succeeded with his choice of Altec Lansing sound system. ‘The next day, I received the ultimate compliment anybody can give to a sound reinforcement system from Ms Violet Oon who was a reviewer for the Sunday Monitor, who wrote: “It was a combination of informality, of drama, of pizzazz and of professionalism. I am no technician, but the music must have been amplified. The wonder of it was that we did not notice it – an indication of the perfect marriage of art and artifice”.’
Sports Hub facts
The 55,000 capacity National Stadium has a 19,500 sq-m retractable roof, which can open or close in just 20 minutes to reveal or hide the entire playing field. Clad in a multi-layer ETFE pillow, the moving roof incorporates a matrix of LED lights, making it one of the largest addressable LED screens in the world. When fully-retracted, 95 per cent of the seats are under cover, although comfort cooling has also been applied for spectators. Although each seat is cooled with 12 litres of air per second, its zero carbon impact green credentials have been earned by offsetting the energy created by the Solar Panels installed on the rooftops. Measuring 310m, it also features the largest free spanning structure in the world. The simple geometric composition of the thin, retractable dome was designed to use only a fraction of the energy required for an equivalent fully enclosed stadium.
In addition to the main stadium, the S$1.33 billion (US$1.06 billion) Sports Hub also incorporates other arenas and centres within the 35 hectare site, including a 6,000-capacity Aquatics Centre complete with leisure facilities and a 3,000-capacity modular Sports Arena. The OCBC-sponsored Aquatic Centre offers a wide range of aquatic facilities, whilst the OCBC Arena is multipurpose in nature and comprises two blocks of multi-purpose halls, accommodating a full range of activities from elite athlete training to public recreational use. In addition, a Water Sports Centre was built to enhance sports offerings in the Kallang Basin and a further 41,000 sq-m of commercial space was made available for leisure, shopping and dining. A Sports Information and Resource Centre (SIRC), comprising a library, a sports museum and an exhibition centre together with a Community Area including a playground, hard courts, skate park, lawn ball, giant chess set, rock climbing and beach volleyball completes the picture.
E&E was tasked to provide intelligibility, high output and broadband pattern control throughout the 55,000 seats. This was ultimately achieved by adopting an EAW QX three-way loudspeaker solution. Following extensive modelling and simulations in EASE 4.2, a combination of 35 QX544-WP (45-degrees h x 45-degrees v), QX594-WP (90-degrees h x 45-degrees v), QX596-WP (60-degrees h x 45-degrees v), QX5641-WP (60-degrees h x 45-degrees v) and QX566-WP (60-degrees h x 60-degrees v) cabinets were deployed at critical points within the stadium.
Whilst each QX model varies in its dispersion characteristics, they commonly combine four 12-inch LF woofers with 2-inch exit MF and HF horn-loaded, coaxial compression drivers within their trapezoidal cabinets. The four phase-aligned 12-inch LF woofers are arranged as vertical and horizontal pairs, which results in extended pattern control in the lower frequency range. The four LF woofers surround the coaxial mid/high compression driver symmetrically in both the horizontal and vertical planes and so the response across the spectrum appears to originate from a single point. In addition, six customised MQX5363-WP speakers have been installed into the highest sections of the roof, for which each system combines eight 12-inch LF and two MF and HF horn loaded coaxial compression drivers.
The common solution adopted in most modern auditoria is to suspend line array systems at various points from the lip of the canopy. The EAW point source system designed and installed by E&E has therefore successfully contributed to enhanced spectator aesthetics. The low frequencies have been further enhanced with the addition of 12 clusters each combining four EAW SB528zP-WP subwoofers suspended in a downward firing cardioid array. A separate EVAC system comprising of 24 Community RSH462 horn-loaded, coaxial, weather-resistant speakers has been installed within the bowl.
During the initial design stages in 2011, Dante networking was a relatively new and untested phenomena, but E&E insisted on adopting it into the core of this extensive network, given its benefits over relatively long distances and multiple locations. Prior to Cat-5 cabling, analogue audio distribution suffered from signal degradation due to electromagnetic interference, high-frequency attenuation, and voltage drop over long cable runs. With the acceptance of digital multiplexing, in which multiple streams of audio plus integrated control data are distributed with sub-millisecond latency, audio cabling requirements have been greatly reduced. Dante provides specific advantages over the first-generation audio over Ethernet technologies, such as CobraNet and EtherSound, by being able to pass through network routers, offering a higher channel count, providing lower latency and automatic configuration.
Digital audio throughout Sports Hub has been enabled by networking over 85 SymNet Edge frames by US manufacturer Symetrix, located in various amplifier and control room racks and facility panels throughout the venue. Having inserted analogue-in, analogue-out and digital-out input cards into the four configurable I/O slots of these SymNet Edge frames, the digital network is configured and managed over the IT infrastructure, transmitting and receiving up to 128 (64x64) channels. The facility managers’ further benefit from the SymVue GUIs downloaded onto PCs and laptops providing instant access remote control.
An Allen & Heath iLive-112 console connected to an iDR-32 Mix Rack has been Dante enabled courtesy of the inserted M-Dante audio interface module. It has been further equipped with a Mic and Digital Input & Output module in addition to an Analogue Control over Ethernet (ACE), RAB2 Remote Audio and Dante Audio Interface module. The M-Dante integrates with the SymNet Edge frames, whilst offering digital microphone splitting, multi-track recording and system expansion with 64-channels of bi-directional audio.
The EAW QX series main stadium speaker system and subwoofers is powered by 28 K2 and 70 K10 2-channel amplifiers produced by Powersoft. Both models measure just 1U height in the racks and hence save space, yet deliver 1,000W and 2,000W of power respectively over 8-ohms. Fully digitally controlled via the network, the K2 and K10 amplifiers come with a KDSP board and KAESOP Ethernet/AES3 interface, which connects to the Italian manufacturer’s Armonía Pro Audio Suite software. Redundant SymNet Edge processors provide AES outputs as main and analogue outputs as a back-up into the Powersoft K Series amplifiers, whilst EAW Greybox DSP settings have been loaded into the Powersoft K Series DSP amplifiers. In late 2013, the Ottocanali series became Powersoft’s first amplifier series to integrate Dante networking, but this breakthrough came too late in the installation to make changes to the specification in Sports Hub.
Wired (and wireless) for sound
An extensive Shure UHF-R wireless system providing audio reference companding serves the multiple announcement needs for Sports Hub. A total of four dual channel UR4D+ receivers together with UR2 handheld transmitters with Beta 58 mic head and UR1 bodypack transmitters with MX150 lavaliers more than serve the venue’s needs. Networked automatic frequency selection and automatic transmitter setup provide control, whilst the RF distribution ports allow up to 10 receivers to share a single pair of antennas. Each channel can offer 2,400 selectable frequencies across a 60MHz bandwidth and up to 40 compatible channels per band. Other features include MARCAD Diversity and track tuning. The Ethernet network compatibility ensures that the personnel can access the Wireless Workbench 6 Control/Monitoring software for their individual and networked receivers.
Owing to the great distances across the stadium, a number of UA845SWB five-way antenna distributors were added, for which each splitter can allow up to five receivers to use the same antennas. Each UA845-SWB expands the wireless microphone system by splitting one pair of antennas to multiple UR4 wireless receivers, whilst amplifying RF signals to compensate for insertion loss due to splitting signal power to multiple output connectors. Located under the roof of the NST Bowl, four UA874 UHF antennas linked to a UA221 antenna splitter/combiner have improved the overall wireless reception throughout Sports Hub. By producing a cardioid pattern towards the coverage area, the antennas reject more RF signals outside the area than standard half wave omnidirectional antennas.
The control rooms are equipped with Microflex MX405 5-inch gooseneck microphones mounted onto MX400DP desktop pre amps. The main source for playback material is a TASCAM CD-500B CD/cassette player, whilst SS-R200 solid state recorders can convert WAV and MP3 files to compact flash, SD/SHC and USB memory cards. Monitoring can either be performed via Shure SRH940 headphones connected to PreSonus HP4 headphone pre-amps or via ADAM A5X speakers.
Four VP89 shotgun condenser microphones encased in Rycote windshields have also been supplied for broadcasting and media applications. The Shure VP89 is a professional shotgun condenser microphone for use in critical broadcast and media production applications. Designed with interchangeable long, medium and short capsules, the VP89 provides scalable off-axis rejection for focus and flexibility in a wide variety of on-site locations and is highly suitable for a venue such as this.
Multi-Purpose Indoor Arena
The 3,000-capacity MPIA adjacent to the main stadium was designed to incorporate a large degree of scalability and flexibility in its layout. The event sound system and announcements are catered for by a distributed audio system comprising of 65 EAW MK2396i 12-inch and 2399i speakers for Halls 1 and 2 on level one. Finished in white, 127 Community DS8 surface mount dual 8-inch speakers have been integrated into the designs of the smaller Halls 4, 5 and 6 of the basement. Forty-six Powersoft Duecanali D3904 amplifiers supply the power throughout the halls of the two levels. Rack mounted in two ELV rooms with 20 SymNet Edge frames, full digital control and Dante networking of the D3904 amplifiers has been enabled courtesy of the integrated KAESOP Ethernet/AES3 interface. The control room within is equipped with the same selection of mixing, playback, recording and microphone equipment as the two in the main stadium.
E&E was also commissioned to provide a sound system into the highly reverberant water sports arena, catering for audiences up to 6,000 spectators during specific events. Three EAW QX564-WP (60-degrees h x 45-degrees v) speaker systems have been combined with 30 MK5399 15-inch two way speakers to provide the overall coverage in this venue. The horns which have been rotated to provide 90-degrees x 90-degrees dispersion are as large as the enclosure size to maintain consistent directivity throughout the HF pass-band. In addition, 22 EAW LS432i line source speakers each combining four 4-inch woofers and three 1-inch tweeters provide nominal vertical coverage pattern of 20-degrees to below 1,000Hz and 140-degrees in the horizontal plain. Once again, Duecanali D3904 amplifiers provide the power whilst SymNet Edge frames were entrusted with DSP capabilities. Live and public announcements together with playback is served by the same inventory as the main stadium.
Just three EAW QX5641-WP (60-degrees h x 45-degrees v) speaker systems powered by three Duecanali D3904 amplifiers suffice for this space, with five SymNet Edge frames providing full DSP. Live and public announcements together with playback are served by the same inventory as the main stadium although a Mackie Onyx 24.4 24-channel console was deemed sufficient for its mixing needs.
Owing to the multi-purpose nature of the stadium, flexibility appeared to be the key component of its design. As such, it integrated features such as moving tiers and palletised turf modules in addition to the retractable roof that will now promote the stadium to offer a wide calendar of sporting events such as football, athletics and cricket in addition to other events such as concerts and the National Day Parade. However, these features had to be added without compromising on the proximity and quality of view for spectators. To date, no other stadium in the world can combine football, athletics and cricket in the same arena.
When the singer Kit Chan performed 'Live Our Dreams' as a tribute to the old stadium during its 2007 closing ceremony, the ghostly echoes must have lingered sufficiently long enough for the government to have heard it during the design stages of Sports Hub. Having insisted on cutting edge technology and design flair, Singapore is now blessed with a National Stadium that is a world away from its predecessor yet exists in the real world. The finely tuned audio network is an intrinsic part of this, going way and beyond the normal scope of playing background music or announcing a lost child.