NBC Olympics Gets Ambitious With Audio
By Dan Daley
The audio for this year’s Olympics on NBC won’t gild the lily: the sound crew is after gritty reality, of which there will be plenty if the run-up to the event is any indication. And that will be enhanced by even more comprehensive surround audio than four years ago. Bob Dixon, NBC Olympics’ director of sound design and communications, notes that this is the first Olympics broadcast to be produced totally in high-definition with 5.1 audio, with some discrete multichannel audio from events that are broadcast live and with upmixed 5.1 from other venues. It’s an ambitious goal, considering that the vast majority of stereo viewers have to be addressed, as well.
“We are still in a period of transition in the United States, so most of our audience will still watch the games on standard-definition television receivers with two channels of audio,” he explains. “This means that everything we do in China must serve both [modes of broadcast resolution].”
But when it comes to 5.1, Dixon explains that the 5.1 experience needs to be consistent and seamless, and thus the need to interlace discrete with upmixed 5.1 audio. “The quality of 5.1 sound brings television viewing to a whole new level of enjoyment, adding another dimension that engages viewers in programming,” Dixon says. “If we were to shift between 5.1 and stereo audio during our broadcasts, our digital viewers would experience quite a shock as sound collapsed to the front wall.”
To avoid that, NBC is employing the Linear Acoustic UPMAX:neo upmixer, allowing the network to incorporate prerecorded or edited stereo content into its broadcasts without interrupting the continuity of the viewing experience. Over 30 UPMAX units are in place in the NBC Olympics broadcast center in audio control rooms, edit rooms, and in the quality control area as a monitoring and troubleshooting tool.
While the system can also be used to create the downmixed audio from the 5.1 feeds to stereo, Dixon emphasizes that downmixes will be done manually. “Since crowd reaction is such a dynamic thing, I don’t want this done by a static formula that leads to announcers getting buried as the crowd explodes,” he explains. “I want this done dynamically in a real mix.”
As complex as the sound stage for the Olympics is becoming, Dixon says they’re not sweetening the production’s audio. “We currently are not using sampling or Foley techniques for post production…at this time,” he says. “The [UPMAX:neo] system will create the upmix, but we create signals going into the device that will help [guide] that process as much as possible. For example, we will not use coincident miking for stereo pickups because of the tendency for any matrix decoder to place coincident signals appearing in both left and right to the center. The end result is a disturbing mono build-up, so we try to keep separation at a maximum.”
Also using metadata, the mix can respond to dynamic changes. “If the surround mix gets hotter in the rear channels, we can [program] it to attenuate those in the stereo mix so they don’t interfere with the announcers,” Dixon explains.
The Right Mic
Dixon says the network will mic more people – participants, coaches and even family members – as the narrative evolves, using both Sennheiser wireless body packs and Audio-Technica BP-4027 shotguns attached to cameras.
“They are terrific for giving a nice soundstage when they get up close to a coach interacting with an athlete,” says Dixon. Even with a built-in delay, these audio tracks won’t be used live but will be mixed in to replays and recorded segments.
Audio-Technica AT4050 condenser microphones are in use for surround ambience applications as well as in the announce booths at the Broadcast Center. The 4050s used for surround ambience will be positioned rather high in the stadium, spread across the field of view from the wide shot of the venue — left front, center, right front — but pointing back toward the crowd, Dixon explains; the same with the left and right surround, but from the other side of the stadium.
“Of course, they could just as easily be on very tall stands at ground level, pointing up to the crowd,” he adds. “Everything depends on the sound of the venue, the cable runs and where we have wires planned to go.”
NBC will use various systems for monitoring audio; some flypacks are paired with Genelec 1031 5.1 systems while NBC-supplied systems at the venues and the Broadcast Center will use NHT Pro 5.1 monitors. Dixon says the systems were chosen based on their ability to translate well between them to keep consistency to the audio.
Processing & DSP
Again, in keeping with the notion that the narrative has plenty of drama and texture of their own, Dixon says even the signal processing of the surround audio isn’t there for enhancement so much as for clarification of reality. “For NBC Olympic audio, our processing is based on problem-solving, not necessarily on creative enhancements,” he explains. “Our consoles are so rich with built-in tools for signal processing that they come equipped to do a lot of the daily chores like limiting, compression and gating, but certainly we have an assortment of outboard gear at the ready,” including the Cedar DNS 1000, Eventide Eclipse, and Yamaha SPX 2000.
Consoles & Mixers
Five 56-fader Calrec Sigma (with Bluefin) provide audio mixing in the Broadcast Center and at a number of events across several venues. The desks have 160 channel processing paths packaged as 48 stereo and 64 mono channels, allowing up to 24-times full 5.1 surround channels. Two consoles will provide audio coverage for both the opening and closing ceremonies. Two other consoles will be used for gymnastics and trampoline, and a fifth will be used for beach volleyball.
At three of the smaller venues NBC Olympics has shed its analog mixers this year in favor of DiGiCo DS-00 digital consoles, which Dixon says provides a 5.1-capable mixing solution in a compact footprint. “The DiGiCo is a size that fills the gap between our large-format desks and the smaller digital formats that were really not suited to 5.1 for television,” he says.
(Two 64-fader Calrec Sigma with Bluefin consoles, each with 320 channel processing paths, are installed at the International Broadcast Center (IBC) in Beijing. In addition, BBC TV will operate one stationary 160-channel 56f Omega with Bluefin console, and SIS Outside Broadcast (formally the BBC OB operation) will use a pair of Calrec 48f Sigma with Bluefin consoles, each with 320 channel processing paths, one in Unit 10 covering the rowing events, the other in Unit 12 covering sailing events.)
NBC Olympics will send six discrete channels of audio with HD pictures to the U.S. from each venue, but will also send a simultaneous two-channel program downmix, as well as a stereo downmix of the sound effects that are used in promos and post-produced pieces.
“We will also be paying the greatest attention to the down-mix of those channels for our stereo-listening audience,” he says.
A Miranda Technologies XVP 811 cross converter card that will convert the HD signal to standard def will actually do the downmix. That two-mix is sent to 30 Rock and the Broadcast Center audio mixers can confidence-monitor that from a network feed from WNBC.