ABC Sports Gears Up To Give Indy 500 Its First 5.1 Surround Sound

By Dan Daley

This Sunday’s Indianapolis 500 marks the 64th year of the race, a string interrupted by neither weather nor war. Each year brings some changes to the race, such as the new mufflers on the Indy Car engines for 2009. And this year’s audio will also have its changes. ABC Sports, which has broadcast the race since 1965, will consolidate track coverage into its own HD mobile units instead of using a world feed as has been done in the past.

“In the past, ABC/ESPN would take the [Indianapolis Motor Speedway Productions] world feed and cut in and out as it needed to,” explains lead mixer Denis Ryan. “This year, we’ve brought in the NEP SS21 fleet, and we’ll be doing the entire race, with our own EFX mix, which lets the audio more closely match the stories they’re following on the field and allow greater continuity to the sound overall.”

This is the Indy 500’s first 5.1 surround sound broadcast, and it will be processed by DTS Neural Surround encoding that reformats and transmits the 5.1 mix in stereo.

ABC/ESPN will take a significant amount of audio from the IMS feed, including their camera microphones, supplemented by ABC/ESPN’s own camera mics, robotic microphones, and fence microphones that were added to the mix during the week before the race. Extra audio coverage is added to the pits, for instance, an area that IMS’s audio doesn’t extend to. Four stereo pairs of Audio-Technica AT835 condenser microphones are aimed at the grandstand, which will hold a reported 400,000-plus spectators.

But they’ll be hard-pressed to compete with the sound of 33 Indy Cars as they throttle up on the green flag. (IMS spends the entire month of May gearing up for its annual race coverage, but the decibel level never reaches its ultimate crescendo until that moment.)

Ryan, who also mixes NASCAR races, says the 835s planted along the outside fence and facing the oncoming and passing cars are a technique used for stock-car races, too. For the 500’s higher speeds — 210-220 mph versus the 170-180 mph that NASCAR racers hit on the straightaways — the Sennheiser 416 and 816 shotguns are spaced farther apart, about double the 15-foot spacing used for NASCAR races. Sony VP-88 microphones are in the infield as “roar microphones,” as Ryan likes to call them.

All the IMS inputs are put into distribution amps from which ABC/ESPN gets its own isolated feed. The iso feed is submixed with ESPN’s own mic inputs and other audio, including team and in-car RF feeds from Broadcast Sports International (BSI). The latter feeds from drivers are submixed and separately monitored for possible live insertion and recorded for edited sound bites for replays or to be used in post.

The surround mix follows the camera narratives, and quick cuts mean a generally conservative surround mix except when the shots are tight: the relative balance of channels stays the same, but the intensity varies.

“We have mostly the microphones from the robotics and trackside in the surrounds, and, when the shot is high and wide, we put a little of that in there; when it moves to in-car, then we add more to the surrounds,” Ryan explains. “It really makes it seem as if the listener is sitting in the middle of the car. Some of that audio is coming from the stereo feed from the car, and the DTS Neural Surround comes into play here because, if you put too much of the same elements into all of the channels, surround and stereo, you can get a comb-[filter]-like effect. The DTS encoding avoids that.”

If there is a nuance to the sound of an Indy Car, it’s the engine. Where stock cars are characterized by the fast changes in rpm as the drivers shift, Indy Cars are pure throttle. “That’s what the [color commentators] are listening for,” says Ryan. “We keep them in the center and the cars in the surround.”