Broadcast 5.1 Audio Remains Challenging

We have unfinished business” where 5.1 is concerned, according to a presenter at the DTV Audio Group forum during the SVG Summit on the business of sports production, which was held in New York City in mid-December, 2014.
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“We have unfinished business” where 5.1 is concerned, according to a presenter at the DTV Audio Group forum during the SVG Summit on the business of sports production, which was held in New York City in mid-December, 2014. As the broadcast industry considers the adoption of object-based audio formats—Dolby Atmos is already available on streaming services—it seems that those schemes are more likely to be adopted for their interactive potential rather than their ability to deliver immersive sound, at least initially.

In the ballrooms of the New York Hilton, audio companies including Calrec Audio, Clear-Com, Dale Pro Audio, DiGiCo, Dolby, DTS, Harman, Lawo, Linear Acoustic, Riedel Communications, RTS, Sennheiser and others plied their wares to throngs of broadcast professionals. Meanwhile, in a meeting room two hallways away, things got a little heated. [Note: In respect of certain television network policies and at the request of numerous participants, the names of all those quoted have been omitted.]

“I think the biggest mistake that we made was to roll out 5.1 in the sports world without a lot of clear definitions,” said one veteran broadcast audio pro. Two decades on from the adoption of 5.1—a format previously marketed as “immersive,” lest we forget—in broadcast, the industry’s ability to deliver a standardized surround sound experience leaves something to be desired. In Germany, for example, “all the networks have standards within their own networks, but then there are standards across networks,” he noted.

Forum participants concurred: “We don’t even agree that the program is 5.1. We never know whether a program is going to be stereo or 5.1, and we don’t have rules for what the 5.1 program should be,” said one.

“We create all this turbulence—it’s stereo, it’s 5.1, we’re upmixing, we’re downmixing. If we just said that the program format is 5.1, we would remove all this uncertainty,” said another. From a program featuring talking heads with dialogue only in the center channel, to a sports event with fully enveloping crowd sound, native 5.1 production can minimize any adverse consequences.

But would a global 5.1 standard work? Soccer fans—outside of the U.S., anyway—express more interest in being surrounded by the sound of fellow supporters, it appears. As one speaker reported, “If I want to hear the field of play, as I was told by my German friends, the kick of the ball is not as important as the chanting of the crowd.”

The switch to an object-based delivery format (various alternate encoding schemes are being considered for the next-generation TV broadcast standard in the U.S.) could allow a viewer to choose between being immersed in the home team or the away team crowd. It could allow him or her to alter the volume level of the commentary, or even mute it.

As one presenter pointed out, there would need to be relatively few changes to current audio signal workflows to implement such interactivity. Simply put, the signals to be made available for viewer adjustment, such as commentary, alternate languages or sound effects, could be fed from the production console direct outs alongside the mix of the remaining channels, or sent back to the network operations center via an alternate path if there are bandwidth limitations.

The big question, of course, is whether or not producers and content creators will relinquish even minimal control—say, adjustment by plus or minus a couple of dB—of any part of the audio mix. “I think monkeying around with the mix is part of the future entertainment experience,” said a participant.

But the personalized experience concept does offer financial incentives, which might help drive adoption of object-based formats. For example, a broadcaster could charge viewers an additional fee for access to certain extra, adjustable elements, such as pit crew-to-driver radio communications.

How those elements might be presented to viewers is still being evaluated. One developer has experimented with graphic interfaces that enable volume level or balance adjustments via on-screen sliders. Another believes that, based on its audience surveys, viewers want simple controls, perhaps nothing more than a commentary level boost button. “Ultimately, it’s about dialogue clarity. We gave choices of multiple things to mix together and it got very confusing very quickly for the vast majority of consumers,” reported a company representative.

“I want it to work as well on my mobile as in my home theater. That means being able to hear the dialogue,” he added. The demand for dialogue intelligibility is what will drive the adoption of object-based audio delivery, many believe, especially on mobile devices, which are often used in noisy environments.

For all the potential of object-based formats to also deliver an immersive sound experience, “The vast majority of consumers are still going to be listening in stereo in five years’ time, largely through stereo TV speakers,” predicted one presenter.

“It used to be only the high-end audiophiles wanted 5.1,” stated a panelist. But as music services evolve and hi-def picture becomes more important, especially for the generation currently growing up to become homeowners, “I think we’re going to see a huge explosion in the next 15 years of people who are looking for a 5.1 experience, be it virtualized headphones, soundbars, surround system, or whatever the next thing is.”