Circle Time

One brand name looms large in the world of high definition television audio. But, choosing a path less traveled, sports network ESPN has been quietly laying the groundwork for their HD presentations by instead testing and implementing SRS Labs’ Circle Surround 5.1-channel audio technology.
ESPN, which implemented Circle Surround 5.1 at this year’s Winter X Games that took place in Aspen, CO in January, has in fact utilized the system previously, according to Ron Scalise, consultant for ESPN remote audio operations. Scalise is thrilled with the performance of Circle Surround, an encode/decode scheme that allows the transmission of 5.1 program material over existing stereo production and distribution infrastructures.

“The first place [Circle Surround] was used was with the NFL on our Sunday Night Football in October, with dynamic results,” he says. “We started the NBA season in November, and I suggested that we bring Circle Surround immediately to NBA, another marquee event. So all the ESPN/ABC NBA games kicked off from the get-go in Circle Surround.”

But what is special about X Games, observes Scalise, is that, as an EOE or ESPN Original Entertainment, it offers the ideal testbed to keep the company on the cutting-edge of broadcast audio. “We’re very much about innovation,” he comments. “Being EOE programming, there are less league-designed, restrictive TV network access rules or regulations with the X Games than in conventional sporting events that multiple networks may cover.

“We have the ability to work within the X Games organization and the competition committee, which allows us to bring technologies to the X Games for production use and R&D for later use throughout other network programming. We try to originate most new technologies at the summer, winter, and X Games Global Championship for other ESPN remote sports event coverage.”

But unlike the fast-paced live broadcasts of the NFL and NBA games, the X Games offered a particular challenge to the utilization of Circle Surround 5.1, he notes. “X Games is a totally posted show, with a quick turnaround. We had one situation with a six-hour turnaround, but generally it’s 24 hours—overnight, as we call it. It’s almost impossible to go live with it, because of efficiency of content and the pace with which we want it to move.”

At X Games VII, nine National Mobile Television broadcast trucks, including five at event locations, were interconnected via a router to eight Avid video edit and three Pro Tools audio edit rooms, all tied to a Unity server. “We take over the first floor of a hotel and turn guest rooms into edit rooms,” explains Scalise.
Audio is stored as OMF files, retrievable at any edit position. “Every venue sends eight tracks or four AES pairs into the router system and any room can accept tracks from any truck,” he continues. “Everything was sent around AES digital embedded.”

The workflow meant that Scalise had to find a method to implement Circle Surround at each venue, yet leave the tracks separated in a way that would allow them to be built or rebuilt as needed — all the while successfully maintaining the integrity of the surround-encoded program. “We combined Circle Surround matrix-encoded tracks with non-encoded tracks, mixed them together, added additional sweetening and sound design, and came up with a successful surround product.”

To his mind, Circle Surround offers certain advantages over other surround encoding schemes, says Scalise. “Other matrix systems are source identifiable, but Circle Surround is not just matrixing, it’s matrixing plus psychoacoustic enhancement. It takes anything with widespread stereo in the front and, frequency dependent, gives you some of that in the rear. It’s the psychoacoustic patent that helps the steering and makes a more realistic environment with a larger sweet spot.”

Scalise trains many of the network’s pool of 40 or 50 freelance mixers on the techniques of mixing with the system. “Circle Surround makes it so simple. It can be inserted into the transmission chain and give you a stereo broadcast that can be made into surround by simply adding a stereo mic for the rear crowd, or any level of complexity by adding sound design and microphones to embellish the project.”

Sound design can maximize the psychoacoustic enhancement to great effect, he observes. “In sports television, most every graphic and replay wipe has a sound effect. I encourage the sound effects department to put a lot of width and movement into these sounds. If you’re listening at home, these sound designs are very intense and impactful, because of the steering and the movement of the sound. That’s something that is exclusive to the Circle Surround process.” Additionally, he says, “When we play music, we get the benefit of this upmix.”

At the Winter X Games, competitors’ family members and friends have their own section at the foot of the downhill courses, presenting an opportunity to add microphones specifically for the rear channels and immerse listeners in the crowd. “I like mixers and editors to place the announcers dead center in the front and submix in an intense course stereo effects mix. We put stereo ambient mics out and have a big left and right crowd. A certain amount of that mix hits behind you, so now you’re in the middle of that crowd. We then add rear crowd and friends and family mics.”

As a result, he says, “It’s like you’re sitting at the bottom of the hill waiting for the finish. You have the event in front of you and the supporters cheering in back of you.”

Compatibility is potentially an issue, but Scalise has all the bases covered. “Half of my job is to make sure it’s tremendously dynamic for high-end viewers, but the other 50 percent is to make sure it translates to the more commonplace viewership, which is stereo or mono. It collapses to stereo and mono tremendously, without a glitch.”

It’s also compatible with other decoding schemes, such as Pro Logic or Pro Logic II. “You don’t get the full Circle Surround decoding, but you get the full response, with stereo rears, full fidelity, and a sixth channel — center rear — that you can feed separately. Or anything common to the stereo rears ends automatically up in the rear center. It even enhances discrete 5.1 cinema mixes.”
As the network starts commissioning mobile units for HD broadcast production, Scalise says he will be recommending that Circle Surround be implemented as standard. “We’re pioneering for HD sports television. My intentions are to send a matrix-encoded Circle Surround signal with the HD. The ease of use and success we’ve had tells me not to do otherwise.
“Our production teams want the process to be seamless when we go to HD. When we first brought Circle Surround to the network, the concern was that it would slow production down or require a different process. This process will allow them to continue to produce shows the way they have been for years and still maintain the pace that they’re used to.”

The process also allows the network to bring the high-def audio experience to viewers with standard-definition equipment. “We’re sending an AES Lt/Rt pair back to the network, and it goes out Lt/Rt to the standard-def people. You take that Lt/Rt pair, decode it with a Circle Surround decoder, and feed a 5.1 AC-3 encoder, which is the ATSC-compliant HD standard. Standard-def viewers receive the same quality and same surround experience as the high-def people.”

For more information on Circle Surround, visit

Surround Professional Magazine