Much of cable technology has centered on improving the video image, but these days there's also a movement toward making a sound investment in better-quality audio.
Several major networks are looking to upgrade program soundtracks to Dolby Laboratories Inc.'s 5.1 Surround sound, to mimic the theater experience.
But it is still more expensive to film and produce video using that format, and at a time when most viewers are tuned into sets that can't relay surround sound, programmers are making careful choices about which content gets the full Dolby 5.1 treatment.
To start with, Dolby 5.1 is not your dad's old digital audio. It consists of five distinct, separately recorded sound channels: left, center, right, left surround and right surround, plus an optional band-limited low-frequency effects channel.
Newer television sets and digital set-tops — particularly those that support high-definition video — increasingly carry surround-sound inputs.
To date, there more than 20 million digital set-tops deployed in North America that carry Dolby 5.1 Surround sound inputs, according to the company.
Driven in part by this consumer adoption, the sound gurus at Dolby have seen a rising interest among TV producers and networks in surround sound.
"A couple of years ago people might have said, 'Well, there's not enough 5.1 content out there.' But now I don't think people can use that argument any more," said Jeff Riedmiller, Dolby's broadcast product manager.
"I think a lot of it is consumers are a lot more aware of it now. Programmers are trying to retain their subscribers by adding a little added value by carrying multichannel audio."
Not surprisingly, the early adopters are the premium movie programmers, including Showtime Networks Inc., Home Box Office and Starz Encore Group LLC, all of which aim to recreate the theater experience.
Broadcasters — most notably Fox — also are starting to make the switch to multichannel audio, particularly as they upgrade to high-definition TV formats, Riedmiller said.
But the same is not true for the majority of mainline cable networks. Among this set, the cost to upgrade to surround sound, plus the fact that the benefits diminish over an analog transmission, serve as deterrents.
"We've approached a lot of [networks], and there are some," he said. "There are some expanded-basic-tier programmers interested in doing Dolby 5.1, but it is not extremely high on the priority list."
While premium channels including Showtime, HBO and Starz Encore have all upgraded much of their movie fare to surround-sound audio several years ago, in response to the rising appeal of DVD movies, they are also starting to add the upgraded audio to their original programming.
Showtime is the only premium service that now sports Dolby 5.1 surround sound on all 32 feeds of its service, including its two HD channels. Dolby 5.1 is available on almost 90 percent of the primetime lineup of Showtime and The Movie Channel.
"We do it because it delivers the theatrical experience right into your home, so with HDTV and even without HDTV, we are giving you the exact theatrical audio that played in the theater," said Glen Oakley, Showtime's senior vice president of corporate strategy and international.
For its part, Discovery Networks U.S. is somewhat more selective in using surround sound. For now, it will add the technology only to HDTV programming.
The education-oriented programmer has recently added two audio suites to process and encode in Dolby 5.1, but don't look for every Discovery show to come with surround sound, said Discovery Production Group senior vice president and general manager Marcos Obidia.
Many times, producers of an individual show will determine if the program is shot using the multiple microphones needed to produce surround sound.
"That's very handy when you are doing movies in a controlled environment," Obedia said. "But sometimes when you are out in the field doing some of those natural wildlife productions, that may not be the best way."