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MADI confidence in ‘largest OB trailer ever’ OB11

The truck is also notable for its comprehensive routing and monitoring system, which includes 25 MADI monitor and line checking units

Its builders claim it is “probably” the largest outside broadcast trailer ever built, but UK supplier CTV’s OB11 is also notable for its comprehensive routing and monitoring system, which includes 25 specially designed MADI monitor and line checking units. The expanding 84-square-metre 5.1, 4k and HD vehicle is now in the general sport and entertainment production phase of its first months on the road, after being launched in May 2014 (see CTV builds 4k truck with Calrec Apollo for 5.1 mixing) and spending the summer covering cricket for Sky Sports.

Many European broadcasters, including Sky, are producing programmes and live events in 4k ahead of any standardisation and wide-scale implementation of Ultra High Definition television. OB11 is the first 4k truck for CTV, which is part of the pan-Europe Euro Media Group. There is currently discussion about the possibilities for spatial sound to accompany Ultra HD but CTV’s head of audio, Ian Smith, says that the new truck “is not a game changer” in this respect, with 5.1 installed to match the company’s other trucks.

The audio room features a 64-fader Calrec Audio Apollo console with Hydra 2 routing. “We have two other Apollos and an Artemis, so this is maintaining consistency over the fleet for our staff and freelancers,” explains Smith. The Hydra 2 connects to an integrated Imagine Communications (Harris Broadcast) router, which is also linked to a MADI routing system.

“The video router makes all the associations so there can be external control of the Calrec,” Smith explains. There is provision for 6 x 64 MADI streams in and out, with embedded signals in the video feeds. OB11 features CTV’s first implementation of the Axon Cerebrum Windows-based IP/Ethernet control and monitoring system. “This talks to the router and the sound desk and other systems, like the 272-port RTS Telex Omneo intercom,” says Smith. “It replaces an old school serial controller. We’ve never had anything so comprehensive before.”

MADI is used for audio distribution within the truck on a 1,024 x 1,024 squared. Smith comments that a four-channel MADI confidence monitor was needed to ensure that everything coming in and out is correct. “We wanted something that was nice and simple on one coax that would allow us to listen to feeds at any time,” he says. CTV has installed DirectOut technology for this on previous OBs but not in a truck. “We’ve used their products for some time but they tend to be either too complicated or too basic. So we spoke to them about a four-channel unit for this job.”

The result was the KYRA MADI monitor, which features a headphone output on the front panel, PFT (power fail through) technology to ensure signal distribution using BNC MADI in the event of losing power and a lockable channel selector. All MADI from the Apollo to the VT and disk recorders, stage boxes and the 25 monitors are router through a DirectOut M.1k2 system.

The sound room features a Genelec 8040 5.1 loudspeaker system. Smith says this was chosen because the suite is “slightly smaller” than those in other CTV trucks but “still adequate”. Dolby E is used to transmit feeds out of the truck, particularly in the case of Sky productions.

OB11 was built by coachbuilder A Smith Great Bentley in association with systems integrator ProjectBuilders, a division of Belgian Euro Media facilities company Videohouse.