Sound Advice For Stations: 5.1 Surround

High-definition television, now well over a decade old, has caught on with American television viewers in a big way. But the Dolby Digital audio, the 5.1 channel sound format associated with HDTV, has lagged far behind—especially at TV stations.

Most stations simply pass through the 5.1 surround sound provided from the networks they carry. But only a few network O&Os produce or mix local 5.1 surround in their own facilities.

“Broadcasters spent millions of dollars lobbying for this amazing media that’s capable of delivering theatrical quality sound and pictures to peoples’ homes,” said Roger Charlesworth, executive director of the DTV Audio Group and a major consultant for networks and shows like NBC’s Saturday Night Live.

”It’s the biggest competitive advantage television has over all the emerging media. I think it’s incumbent on stations to exploit it.”

Yet, few local broadcasters can even hear the surround sound they are broadcasting. Most stations have no 5.1 monitoring facilities, leaving many of their viewers at home with far better sound systems. Some stations have upgraded their facilities for HDTV and actually have mixers capable of 5.1, but don’t use them for that purpose.

“One of my previous clients was an audio console manufacturer who sold a lot of surround sound consoles. When we wanted to learn how many customers were actually mixing in surround sound, we couldn’t find one,” said Howard Mullinack, director of marketing at Linear Acoustic, a maker of automated surround technology for broadcasters.

“With station staffs being reduced, it’s more of a challenge than most broadcast stations are ready to take on right now,” Mullinack said. “It means they need to equip their facility with surround sound monitoring. And they have to take into account that most of their audiences are not hearing the surround mix. They are hearing the downmix. It you mix in surround, you have to keeping checking your downmix.”

Uneven program loudness and disappearing center channel dialog have dominated viewer complaints since HDTV arrived.

Loudness problems occur due to the use of multiple program sources with uneven sound levels being mixed in the TV station. The result is that viewers hear varying audio levels at home as the content changes.

Center channel problems occur when the key dialog—whether a narrator, on-camera announcer or interview subject—shifts from the front to side/back channels or disappears entirely. This is usually caused by sloppy audio placement in surround fields. 

In November 2009, the Advanced Television Systems Committee published ATSC A/85, a list of recommended practices for handling the loudness of television audio. It went a long way in clarifying the problems and offering solutions.

Geir Skaaden, VP of North American licensing for DTS, a manufacturer of surround sound technology, said it's necessary to put loudness solutions in the receiving devices, the set-top boxes of TV sets. “Loudness technology is needed at both the television station and in the home,” he said. “That will be necessary to completely solve the loudness problem.”

Manufacturers, including DTS,  Linear Acoustic and Dolby, now offer refined audio processing equipment to address the problems at the station level.

These automatic devices, many priced from $10,000 to $25,000, work well and keep broadcasters “legal” with regard to loudness issues.They are not creatively “accurate” as to placing sound elements in the proper sound fields. And they often serve as a crutch, giving stations an excuse not to upgrade to full 5.1surround production and monitoring.

“There are no automation systems available today that can take care of all audio problems,” said Roland Vlaicu, director of technical marketing at Dolby Labs. “The human factor is needed to analyze the problem and come up with the right solution to fix it. I don’t think there will ever be a time when audio experts are not needed at a television station.”

Charlesworth said it is particularly important for network affiliates to adopt 5.1. “The network productions are getting richer and richer,” he said. “The commercials are immersive, they are in 5.1 and they are very dynamic.

“I know it’s a hard leap to make, but it’s the logical next step. It’s that turbulence at the format edge between stereo and 5.1 that drives stations crazy.

“Local stations need to understand that surround sound doesn’t mean flying spaceships around. For the local news show, we mean putting talent in the center channel, putting stereo music in left front, right front and remixing theme music to be more immersive.”

Contrary to popular belief, doing local 5.1 surround does not change a station’s workflow in a major way and does not cost more in terms of equipment or personnel, he said.

Today’s HD-SDI infrastructure carries as many audio channels as a station desires. Virtually all digital audio mixers now include built-in 5.1 technology and it has come a long way in ease of use.

A few stations, mostly network O&Os in major markets, have begun a 5.1 transition. A leader is KPIX, the CBS O&O in San Francisco.