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AUDIO FOR HD & 3D - UEFA CHAMPIONS LEAGUE FINALMatt Bell looks at looks at how Sky Sports OB audio workflows have evolved to cope with live championship football

in high-definition 3D & 2D, with 5.1 surround sound

European satellite broadcaster BSkyB

was one of the worlds first to begin

regular high-definition transmissions to

a consistent technical standard; its HD

Sky Sports channel launched in early

2006 after several years of behind-the-

scenes preparation.

Skys control over its broadcast chain, fromproduction to satellite distribution, meantthat it could re-write the rules for its newHD workflow as required, but the lack ofa technical precedent to follow meant that

the company had to invest vast sums in thenecessary production, post and transmissioninfrastructure, and work with manufacturersto develop much of the technology itrequired for HD broadcast. The transitionalso meant that Skys OB facilities partnershad to invest in HD-capable vehicles, mostof which had to be built from the ground up.

After many trials and much discussion, Skypublished a detailed technical specificationfor every element of its HD production and

broadcast chain, ensuring that even whenit was working with equipment providedby third parties (such as its OB partners

trucks), the complement of equipmentprovided for its use would always be thesame. The spec of the service was fixed atMPEG-4-compressed 1080i video, with 5.1surround sound where possible, and stereoaudio otherwise.

The HD service began with football andrugby matches (although cricket, golf anddarts followed). To achieve the requiredaudio standards, the agreed plan forfootball stadiums was to capture the overallambience of the venue in 5.1, and then use

further spot mics at pitch level to add close-up detail, such as the ball being kicked, andplayers cheers. Mindful of the fact that manyof their subscribers would still be listening instereo, Skys engineers designed the audioworkflow so that folding down the 5.1 mixesto stereo would not cause phase problems.They avoided the use of multi-mic arrays,which they felt could not be guaranteedto produce phase-coherent audio in everypossible broadcast situation, and insteadworked with UK microphone manufacturer

SoundField to develop a digital, pointsource microphone system, the DSF-2.This microphone system outputs phase-

coherent 5.1 audio which can be collapsedto stereo (or even mono) without generatingphase artefacts.

To the output from the DSF-2, Sky addspitch-level detail from a group of Sennheiser416s placed in custom coloured Rycotewindshields around the pitch and overthe tunnel through which players enterthe stadium (usually 12 in total). A moredirectional Sennheiser 816 is attached to aswivelling camera on the half-way line, Leftand Right fill mics are placed at either end of

the stadium (usually Sennheiser MKH20s),and radio mics are attached to Steadicamsused near or on the pitch itself. (Collectively,these pitch-side ambient mics are known atSky as the Effects mics.) The outputs fromall of these mics are fed back to OB vehiclesequipped with Calrec mixing consoles. In theearly years of Sky HD, Calrec Alpha deskswere used, but the new Apollo consoles arenow replacing these.

This standard set-up has been used mostly

unchanged on the stadium-based eventsSky has covered in high-definition since2006, but it has varied for large-scalefixtures. To find out more, I spoke to twoOB engineers from companies that haveprovided HD OB facilities for Sky Sportsfrom the beginning: Neville Hooper of NEPVisions and David Rowley of Telegenic.At the time of our conversations, theirmost recent job for Sky was overseeingcoverage of the UEFA Champions Leaguefinal at Wembley Stadium, Hooper takingresponsibility for the 2D coverage and

Rowley the 3D. The task was in every senselarger than average, with Skys HD coverageof the final being beamed to over 25 foreignbroadcasters around the globe via theEuropean Broadcast Unions satellites, inaddition to Skys own channels.

NEP Visions deployed its latest pair of HDvehicles, collectively known as Gemini, tohandle the 2D coverage and the so-called

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World Feed which was distributed viathe EBU. Gemini is two trailers which actas Skys match and presentation trucks,explains Neville Hooper, Deputy Headof Sound at NEP Visions. One truck hastwo audio production control rooms, eachwith a Calrec Apollo, and the other has thevideo control room, and the recording/slo-mo video playback area. The match wasmixed on one of our Apollos, the openingceremony, pre- and post-match interviews

on the other. The feeds from the gamewere distributed to the EBU, terrestriallyand via satellite. The trucks were parked inthe underground broadcasters compoundat Wembley Stadium.

For the match itself, Gemini only producedpictures and audio from the Effectsmics; NEP Visions had a separate truckproviding Skys commentary, while theforeign broadcasters commentary wasproduced elsewhere in Wembley, in aseparate Commentary Control Room

(CCR). A TOC (Technical Operating Centre)by the stadiums East Gate took feeds ofGeminis video and Effects-only audio,and was responsible for ensuring that theforeign broadcasters, whose trucks wereparked near the TOC, added the correctcommentary from the CCR to their feedof Skys coverage. The TOC gave all theforeign broadcasters one central point torefer to if they had any problems with our

feeds, explains Hooper. An exception wasmade for Telegenics trailer, which lookedafter the 3D coverage of the event; it wasparked next to Gemini and took direct feedsfrom it.

The process of setting up the equipmentand the feeds in between the various OBvehicles and the TOC took five days. Itwasnt just a case of driving the trucks intothe compound and putting the usual micsout, comments Hooper. For example, Skyhave permanently installed SoundField

DSF-2s at a lot of football stadiums in theUK, but not yet at Wembley and weddecided we wanted more than one for thisgame anyway. We had one very high upunder the roof, and one on the standard TVgantry. We put up a pair of high-slung omnisabout level with the 18-yard line, the Spatialmics. There were also mono DPA shotgunmics, configured as stereo pairs, behindeach goal, pointing up at the crowd, and 16Sennheiser 416s around the pitch instead ofthe usual 12.

There were extra beauty shot cameras,including one on a helicopter run by Aerial

Camera Systems, continues Hooper.Within the stadium, we associated the highbeauty shots with the highest SoundField,so that the ambience for that shot was ininstant 5.1. There were three radio camerasin the stadium with mics, and a radio-linkedSennheiser 416 on a boom pole goingaround with one of the Steadicams, to getadded on-the-spot pictures and sound, forexample during the coin toss at the start.And when Barcelona were throwing theirCaptain around at the end, the pole mic wasright in there, which was great.

We also had to lay all of the fibre-opticfeeds round to the TOC and the CCR, testall the radio mics, and interface with AerialCamera Systems. Just getting the commsset up to talk to all of those people is oftenthe biggest part of the job. The audio feedswere sent to the TOC embedded in thevideo feeds, but we also sent two MADIstreams as a backup, and analogue feedsvia multicore, in case anything went down.Supplying the Telegenic truck next door was

fairly straightforward we used AES overMADI for the audio, again with analogue viamulticore as backup.

Wembley WayStereo

Beauty Stereo

Tunnel Stereo Radio Pole

Far Right CenterFar Left CenterFar Right 18

YardFar Left 18

Yard

LeftStereo

RightStereo

RightHung Spatial

LeftHung Spatial

GantrySoundfield

GantryStereo

Roof

Soundfield

Far RightGoal

Near RightGoal

Far LeftGoal

Near LeftGoal

Near Left 18Yard

Near Right 18Yard

Center Line

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2D to 3D

Although the visual side of 3D broadcastrequires separate stereoscopic cameras,the audio side is more straightforward. Skyspreferred audio format for 3D broadcast is5.1 surround, as on its 2D coverage. Theearliest 3D outside broadcasts on Sky inSpring 2010 were made using the 5.1 mixbeing transmitted with the 2D pictures,but as David Rowley, Telegenics Head ofSound, explained, this soon changed. In thebeginning, we just took a clean Effects mixfrom the 2D truck. But different production

values have to be applied for 3D broadcast.Viewers have to be given time to absorbthe 3D content, so theres not as much fastcutting as there is in 2D. And that meansyou need a separate commentary teamand a separate Effects mix to complementthe picture. We usually take in every sourceseparately over MADI from the 2D truck the pitch mics, the SoundField mic, and anycamera mics that were taking feeds from and our Sound Supervisor does a mix for3D.

The scope of the Champions Leaguebroadcast necessitated some compromises.Neville Hooper: With all the foreignbroadcaster commitments at the final, wedidnt have enough MADI streams available,so we sent the 3D truck a premixed feed ofpitch-side mics what we call the Ball KickGroup as a premixed feed. We still hada number of discrete feeds, including thosefrom the SoundField mics, to add to our mixthough adds David Rowley.

Fortunately, continues Hooper, onCalrecs MADI I/O boxes, you can feedout of the optical and co-axial outputs atthe same time, so we could double up onsome of our feeds in the compound, one oncopper and one on fibre, when we neededto send the same signal out to two differentdestinations.

In the near future, the hope is to streamlinethe tangle of MADI and analogueconnections, as Rowley explains. Weve juststarted experimenting with Calrec stageboxes using Hydra 2, the audio networkingprotocol on the Apollo. The idea is tonetwork the commentary positions to themain desk with remote Hydra stage boxes,using the built-in fibre connections thatyoure starting to find in the major stadiums.We used two fibre-connected Hydra 2boxes out in the stadium to bring in thepitch mics at this final, adds Neville Hooper.

Rowley continues: Were hoping this will beour standard way of working by next year we already use the older Hydra 1 boxes withCalrec Alphas on our Rugby coverage. Ouraim is to use less copper cabling than wedo at the moment; it can be susceptible tohum and wiring faults, and the rigging timeis much longer, because there has to be somuch of it.

Mixing

Telegenic and NEP Visions adhere to astandard console layout when working forSky, with pitch and Effects mics routedto the fader channels on the Apollosleft, and group faders assigned to theright side. These carry submixes like theaforementioned Ball Kick Group, andthese are usually routed to both the mainoutput mix containing commentary, and theclean, Effects-only mix onto which othercommentary can be layered. Commentaryis always mixed exclusively to the Centre

channel, although studio-based discussionsfeaturing multiple commentators, such asthe half-time analysis, are mixed across thefront three channels to give a wider spread.

Generally speaking, mixing for football isvery much a hands-on event for SoundSupervisors, as David Rowley explains.Theyre forever trying to second-guess

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the players. If the action goes to a cornershot, for example, there will be a corner micmainly covering that, and also the goal mic

and the 18-yard mic will be present in themix at a lower level. What most Supervisorswill do in that case is ride the goal fader ifthe ball heads that way from the corner, orride the 18-yard mic if it gets kicked up thepitch instead. If you watch an experiencedFootball Supervisor at work, theyreconstantly fading up combinations of mics,and fading down others. Over time, they do

develop a feeling for where the ball is likelyto go next.

Thanks to the care taken when originallyspecifying the micing systems for Skys HDcoverage, stereo fold-down compatibilityof the 5.1 mixes produced for the 2D and3D broadcasts is excellent. Neville Hooper:The Apollo desk automatically creates aDolby Pro Logic-encoded LtRt mix at thesame time as the 5.1 mix. We never haveany serious problems at the downmix stage

now we went through all of that pain in2005! The standard format for each ofthe eight-channel audio output feeds fromthe Calrec Apollo on a Sky transmissionhas the downmixed stereo LtRt mix for SDtransmission on the first pair, containingSky commentary and the stadium Effectsmix, then a similar LtRt stereo mix on thesecond pair which lacks the commentary,to which international commentary canbe added. The third and fourth pairs alsofeature with commentary and cleanEffects-only mixes, but in Dolby E-encoded

5.1. For the Champions League final, thisstandard arrangement was again varied toaccommodate extra foreign broadcastersand UEFAs own commentators.

A Model Broadcast

As a testament to all of the carefulpreparation involved in its broadcast, theChampions League final was seen on TV byan estimated 300 million viewers worldwide,

in addition to the 87,000 spectators packedinto Wembley Stadium in person andthere were no on-air hitches. It was a verylong week, but the broadcast went offwithout any problems, comments a relievedNeville Hooper. There was nothing to makeviewers sit up and wonder what had gonewrong, anyway and thats what werethere to achieve.

Calrec Audio Ltd

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