Live from London: NBC Olympics audio finds sweet spot

NBC audio mixers On-hand in London

The London Olympics mark the third time that the Olympics have been produced in 5.1 Surround Sound and, in many respects, it appears that the third time is the charm. Bob Dixon, NBC Olympics, director of Sound Design & Communications, says that the quality of the audio is the best yet, reporting that the quality of audio in the NBC Olympics Listening Room, both the outgoing and return paths from the U.S., as well as reports from viewers in the U.S., all point to a successful listening experience.

The reason for the increase in the quality of the audio is not only steps that the NBC Olympics team as taken with respect to processing of 5.1 Surround Sound signals but also steps taken by the audio team at Olympic Broadcast Services as this is the third Olympics that OBS has done in 5.1. Understanding 5.1 audio production is not something that can be learned overnight. And it can be especially challenging for a production team that may only have a chance to work with each other every two years. But this year nearly everyone involved has had enough experience working in 5.1 to really get the most out of the production.

“You’re dealing with people from all over the world [on that production team] and you need to communicate what you want to produce and then help the engineers understand and then achieve it,” he explains. “It’s a learning curve.”

At the core of NBC Olympics audio philosophy is the goal of creating a realistic bed that has three key components: the ambient sound of the crowd; sound from the field of play; and then the announcers. By keeping those three elements separate as much as possible and then bringing them together on the Calrec mixing desks, NBC Olympics can deliver the ultimate experience.

“Some people prefer to hear the announcers spread out a little bit over the left and right channel for a fuller sound but it ruins the ability to re-voice things down the line and makes it much harder to do voice overs because if you need to replace a voice the announcers are bleeding into channels one and two,” he explains. “So we think keeping the voice in channel three can help us make the voices more robust, clear, and present.”

By having the commentary track within its own channel, the team can also more easily and accurately up mix stereo effects, creating audio for the the left and right rear channels out of the two front stereo channels.

“When you put an announcer track through an up-mixer it refocuses the energy and pulls everything into the center, making it sound more mono,” says Dixon.

Also playing an important role is the Linear Acoustic Aero.qc 2, which combines ITU-R BS.1770 loudness monitoring with Linear Acoustic AERO-style multi-band processing and UPMAX 5.1 with AutoMAX up-mixing algorithms.

“If the Aero.qc sees the announcers on channel three it passes them through and then up-mixes channels one and two to create the output for channels five and six,” adds Dixon.

While the new Aero.qc is an addition to the NBC Olympics audio arsenal one omission is compressing the announcer channel, something that is often done to limit the dynamic range of an announcer who may yell one minute and whisper the next. If the compression is linked to sound effects (or if crowd noises bleed into the announcer’s microphone) the effects will also get louder and softer.

“When the announcer is not talking loudly and the effects are at inconsistent levels it can sound pretty bad,” says Dixon.

Also new for NBC Olympics this year is a system developed by Tieline Technology of Australia that allows for better communication between the production team in the IBC or truck and the announcers.

“We can now control whether or not a mic is on or off and also can send separate IFB to each announcer,” says Dixon. “There is also a second line so we can feed them a mix-minus signal without the announce signal or audio from a studio or the mixed zone.”

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