Comcast's new studios do HD and surround

Comcast’s event-control room includes two Sony 24-inch HD monitors and KRK monitors equipped with 5.1 surround-sound monitoring. Photos by Dave King. Photo illustration by Robin Morsbach, associate art director.

On April 12, 2004, the Philadelphia Phillies Major League Baseball team took the field for their inaugural home game against the Cincinnati Reds at Citizens Bank Park, with simultaneous HD and SD broadcast production taking place in Comcast SportsNet's (CSN) newly refurbished Wachovia Center facility. The unusual thing about this event is that the Wachovia Center is several city blocks away from the actual stadium.

The 24-hour regional sports network has broadcast HD video with 5.1 audio for a selection of games since 2003 from an HD mobile unit shared with the Comcast SportsNet Mid-Atlantic network, which serves Washington, DC, Baltimore and the surrounding areas. The two networks wanted to maximize the number of HD events each carried, so they developed a plan to send the mobile unit to Mid-Atlantic full-time and replace it with a permanent facility in Philadelphia.

The process

In November 2003, the network stripped its original SD production suite bare and the design team began installating the new HD facility. To cover all three sports from a single production facility, the ballpark microphones had to be connected to the audio mixing booth through a series of conduits more than a mile long. Bexel BBS Fiber laid a 72-strand, single-mode fiber to connect the various audio devices between the two sites, as shown in Figure 1. A Solid State Logic C-SB remote mic stagebox under remote control by the SSL C100 digital audio console handles the remote capture of mic signals and selected cue feeds back to the ballpark. The new facility uses Telecast Fiber Systems' Adder 161 and Adder 8821 units for intercom and IFB.

Figure 1. Location and interconnection of the digital audio console components, showing power and signal redundancy. Long-distance fiber and CAT5 connections provide remote signal acquisition and diagnostics, respectively. Diagram by Andrew Clark/SSL Click here to see an enlarged diagram.

The mic stagebox uses multimode fiber for runs up to 1800 feet. But, for the Comcast installation, Solid State Logic developed a single-mode fiber option that could transport audio signals up to 15 miles. The option has redundant fiber and power supplies, supporting 48 analog mic preamps, 12 line outputs and a headphone jack for local confidence monitoring. Announcer mics, camera/field mics and PA feeds currently occupy two-thirds of these inputs.

Sports in 5.1

In addition to controlling the C-SB I/O unit, the SSL audio console provides facilities for fast and accurate 5.1 audio production. Mixing in 5.1 can be a daunting prospect for engineers who have not experimented with the possibilities of the format, but Mike Giacalone, lead audio mixer for Comcast, has developed his own rules of thumb to anchor the mix to the picture, while still using some artistic license to bring home the excitement of being there.

To do this for baseball, Giacalone places the crowd ambience only into the rear of the mix, using a mixture of Crown and Shure stereo mics slung above the fans in left-center outfield to pick up the excitement and reaction of the crowd without highlighting individual fans. He blends front effects and a few home-plate shotgun mics sparingly into the rear as well to give a fuller sound. The Sennheiser shotgun mics on the low-angle cameras also go partly to the rear, although not hard panned, to avoid mismatching the audio and picture when the director chooses one of those cameras.

Announce mics are locked into the center channel. In addition, the three spot mics pointing toward the plate from the catcher and baselines are panned as they appear, except that the center mic uses the console's divergence control to place it in “phantom center,” feeding signal equally to left and right buses. The audio mixer uses the music, effects and PA sources to create each broadcast's LFE signal.

An SSL C100 digital broadcast console generates 5.1 surround, stereo and mono mixes for production and distribution to Comcast SportsNet’s two stadium locations: the Wachovia Center basketball/hockey arena and Citizens Bank Park baseball stadium.

In a typical production, there may be six different mixes for the various network feeds, including simultaneous 5.1 mixes for HD, international, NBA and MLB feeds, and surround-effects stem, plus stereo for analog TV.

Multichannel replay

Another major audio challenge in any HDTV environment is the replay of 5.1 sources, such as effects, music or even the action replays. The facility uses a 360 Systems' Digicart with Dolby E encode/decode units wrapped around them to allow 5.1 audio through their two-channel interfaces. The facility has upgraded three EVS servers for eight-channel operation and uses them for dual format, simultaneous 5.1 and stereo. Other stereo sources are synthesized to surround either with an outboard device or, more often, in the SSL console.

With the flexibility of its new production facility, Comcast SportsNet is able to produce home games for all three teams from a single live-event-control room. Although the baseball stadium is 6000 feet away, to operators in the new Wachovia Center, it feels like it is located next door. The new facility allows the network to deliver exciting and realistic major sporting events to its viewers, while raising the bar for modern sports production.

Bob Ayars is vice president of technical operations for Comcast SportsNet.

Equipment list

Solid State Logic

The Wachovia Center machine room connects the console with the stagebox at Citizens Bank Park via 5200 feet of redundant single-mode fibers.

C100 audio console
C-SB stagebox


MKH416 shotgun mics
ME67 mics

Shure VP88 stereo mics

Crown PCC 160 mics

KRK V8 loudspeakers

Alesis Monitor One loudspeakers

Telecast Fiber Systems Adder 161 and Adder 8821 interfaces

Wohler audio monitors

EVS HD-LSM servers

360 Systems Digicart/E rec/rep machines

Dolby 571, 572 and 569 encode/decoders


HD-CAM 2000 VTRs
Digital audio router
Processing and distribution
HD cameras
MV8000 switcher

RTS Adam system

Design team

AF Associates:

Graham Bentley
Randy Silverman, lead engineer

Comcast SportsNet:

Bob Ayars, vice president of technical operations
Dave Finocchiaro, assistant director of engineering
Mike Giacalone, lead audio mixer
Dick Miller, director of engineering