Advanced Router Tech Changes How Audio Is Done

By Dan Daley

When Major League Baseball opened its new broadcast and postproduction facility in Secaucus, NJ, in January, it took advantage of the rare opportunity to start from scratch. “We wanted a full embedded plant for all of our audio and video,” says Brad Cheney, engineering manager for the 140,000-sq.-ft. space, which will serve as the league’s broadcast nerve center during the season as well as create original programming produced in-house by MLB Network and MLB Productions.

The facility is tapeless for everything except archiving, and with up to 15 games in a 24-hour cycle coming in with multichannel, stereo, and foreign-language audio, a complex routing system was called for. An Nvision model 8576 1,152×1,152 hybrid A/V router is the core, serving the entire facility from content ingestion through postproduction. Two smaller Nvision hybrid routers are dedicated to set monitoring and graphics.

The house format is HD-SDI video with embedded audio, with AES audio available as a secondary format. The HD-SDI interfaces provide for 16 channels (eight pairs) of embedded 48-kHz, 24-bit audio based on the SMPTE 299M standard, and Brad Cheney, an engineering manager for MLB Network, says all 16 of them are used most of the time. “Baseball is a sport that uses a lot of audio — 5.1 and stereo streams from both teams, nat[ural] sound mixes, home and away radio, international radio — a ton of sound,” he explains. “In a Yankees game, we’re getting audio from the YES Network and from Spanish-language broadcasts, and it’s all on a single video signal, because we needed this to be a one-stop shop.”

Audio elements are broken out of the stream using a Harris/Leitch X75 up/down/crossconverter and HD frame synchronizer. The unit’s 16 channels of internal audio processing include timing with video for lip sync corrections, level control, analog-to-digital and digital-to-analog conversion, and embedding and de-embedding for SDI and HD-SDI serial digital signals. “We use it to convert and re-map any type of incoming audio to our in-house standard,” he says, keeping the HD-SDI consistent throughout the plant.

The MLB Network’s acquisition group gets its own audio breakout, using a Ward-Beck AMS16-2AM embedded audio monitor, which can select between HD- or SD-SDI with embedded audio with two reclocked outputs on the rear panel and display the audio signals on the 16 bar-graph meters, outputting discrete audio. “This is a new and really useful aspect to our QC capabilities,” says Cheney. “A lot of thought went into the entire approach to signal routing here.”

The increased capability and larger matrixes on newer audio routers are giving truck fleets more capability. Paul Bonar, VP of engineering for Game Creek Video, says the combination of PESA and Nvision routers on the company’s trucks at the Super Bowl in 2008 were critical for handling the complex audio for the event, noting the larger variety of sources coming into trucks, all of which are routed, and in some cases processed or converted within the router. “We’re running fiber-optic cabling between the trucks,” he explains, “making one large router out of several of them and able to put the ‘chunks’ of audio in each router closer to the places they need to be at an event and eliminating huge, heavy runs of copper.”

Kevin Callahan, senior engineer for Game Creek aboard the company’s Fox truck, says an important function of truck-borne routing is setting the delay within in them rather than using an external device for synch, as well as to compensate for latency from format conversions of the incoming feed. Another feature on the PESA router in the Fox truck is its ability to adjust gain within it, changing mic level to line level, if necessary, and creating compatibility between +4 plant levels and +8 return feeds. “And if you were to lose all the analog inputs of your console,” he says, imagining a worst-case scenario, “you could use the inputs from the router if you absolutely had to.”

The next truck off the assembly ramp at the company will have all its embedding of audio done within its router, Bonar adds: “It’s a far cry from the 122×122 router we started with 16 years ago.”