Yamaha Electronics' DPX1100 projector and HX series speakers in a living room setting. (Photo courtesy Yamaha Electronics)
Television broadcasters have been transmitting MTS and SAP channels since the mid-80s, so there’s no doubt that stations have long ago emerged from the audio dark ages.
But what are they supposed to do with the 5.1 channels of Dolby surround sound as they make their transition from SD to HD?
HD Technology Update turned to Omneon Video Network’s Paul Turner for a disinterested, impartial view of audio-related issues facing stations as they make the transition.
HD Technology Update: From your travels to stations, what are engineers and management thinking about doing with 5.1 channels of surround audio as they make the HD transition?
Paul Turner: That issue is often forgotten. What are you going to do with those extra channels?
HDTU: Well, what’s the prevailing thought in your experience of those who have considered surround sound?
Turner: Is it acceptable to do stereo, or will stations be forced to do 5.1 production? Within a newscast, doing 5.1 may be pointless. But one or two of our customers have taken stereo audio and external multiplexers to turn their stereo audio output into 5.1. These customers find it unacceptable that home (5.1 Dolby Digital) rear speakers are mute.
There are two who insist on having the ability to put room tone out of rear speakers, which produces a more acceptable experience. Without doing so, a switch from a movie to a local announcement or local avails can be quite noticeable.
When you watch video edited by non-professional you can tell because room tone goes away. Professional moviemakers and TV makers, however, have known this for years and now have to apply the same consideration to HD for television.
One thing is for sure, the consumer is getting used to really good audio from DVDs.
HDTU: So DVDs are affecting consumer expectations? It's not just about video but also audio?
Turner: I’ve asked friends who watch DVDs about their opinions of the quality. I’m interested in their perception, especially when watching a letterboxed presentation.
Do they really like quality of video? What makes it look so good? All of them say they like the higher resolution. The reality is it isn’t higher resolution. If you look at a letterbox, a third of vertical resolution is gone and you’re getting no more pixels horizontally. Granted, there is no noise in the black and dark blue, and we are not used to that in NTSC.
However, you can’t really hang your hat on dark blue as dark blue. I will buy into a lack of ghosting and overall lower noise. That’s absolutely right.
The other thing that drives people’s viewing experience is surround sound. It’s not just the domain of home theater. People are buying a surround sound decoder pre-amp for $200, keeping their old speakers and adding new speakers for front. It’s fairly common.
On top of that listeners’ tastes have become attuned to the quality of CD players. It’s pretty darn good, and people’s tastes now attuned to that quality. And that will be the case as we move to HD.
They are also going to expect the same thing out of the audio from a television station. Stations have to consider what they are going to do.
HDTU: Since the vast majority of HD programming being broadcast comes from the network, mixing for a surround audience at the local level isn’t a big issue yet. But a handful of stations are doing local HD origination, including news. How is the surround issue being handled with news?
Turner: The stations can say, “The only thing I produce is news, and I am going to stick with stereo.” But a consideration is the perception of the viewer when sound in general disappears from rear speakers.
People have done tests with the public and they have gotten these responses from the public.
One extremely high-profile customer of ours is insistent that a stereo matrix encoder be used to turn their audio into 5.1 to get room tone. Viewers regard the fact that the encoder put something in all the speakers as a positive.
HDTU: So it’s all about the audience’s expectations and not being perceived as having taken something away that the audience has grown accustomed to?
Turner: Psychology is all over the TV industry. We rely on psycho-perceptional factors for video to work at all. We all look at a series of still images presented very quickly to trick our brain into perceiving motion.
This is nothing new; it’s just another wrinkle, but something to consider.
Tell us what you think!
HDTU invites response from our readers. Please submit your comments to editor@broadcastengineering.com. We’ll follow up with your comments in an upcoming issue.
