Digital Cable, Digital Satellite and HDTV, Dolby Pro-Logic and Dolby Digital
Published October 5, 2002
Q: I just got a new high definition big screen TV. Now that it is hooked up at home, it doesn’t look good at all. It looked great in the store. I use digital cable. Won’t that give me a picture that is digital quality?
A: If by digital quality you mean high definition, the answer is no. Digital cable is just a different way to get a signal to your television set. As you have it now, all digital cable does is transmit regular analog TV signals in a different fashion. At the cable center, the TV broadcasts are converted into a compressed digital signal and sent over the wires to your home, where your digital cable box converts the signal back to an analog signal for viewing. This signal compression allows more signals to be carried by the same cable line. When digital cable was introduced, cable companies had a choice: offer a higher quality picture while broadcasting the same amount of channels, or offer a lower quality picture with more channels and pay-per-view options. Almost every cable company opted for the latter, and in many cases digital cable’s picture is actually inferior to what you can get from traditional analog cable! This is just for the regular programming you are watching today. High definition signals are totally different from analog signals. If you think of analog television as English and HDTV as Chinese, you will get an idea of the difference. The signal is totally different, like a different language that has nothing in common with the NTSC broadcast system we have used for fifty years. Digital cable has the capability to carry HDTV signals, but you need a special converter box and the cable company needs to be transmitting the high definition signal. There are very few cable companies that do this,…well under ten television markets in the United States. This is why you will very rarely find digital cable used by serious video buffs or knowledgeable big screen television owners. The FCC has been in discussion with the major cable operators and is anxious to have them commence broadcasting in high definition. With a combination of incentives and arm-twisting, they have convinced them to start offering some high-definition content starting in 2003. (Adoption of HDTV has generally been behind schedule so don’t hold your breath when considering that.) When high definition cable does become available, you will need a special converter box to receive it, and not all the programming is available in high definition. The standard programming will look exactly as it does today, lousy. To get the most out of your new TV, use a satellite service such as DirecTV or Echostar’s Dish Network. Satellite services offer far better picture quality for analog broadcasts, as well as carrying true high definition broadcasts that can be watched with a special satellite receiver.
Q: I don’t have a Dolby Digital receiver, just Dolby Pro-Logic. Can I still get surround sound?
A: Surround-encoded DVDs have Dolby Pro-Logic as well as Dolby Digital surround information. If you have a Pro-Logic system, simply plug the red and white outputs into a pair of inputs and turn on Pro-Logic, and you will have surround sound. It lacks some of the features of Dolby Digital such as a subwoofer channel or separate left and right surround speakers, but will sound crystal clear with the output of a DVD player. Some older movies recorded in mono may not have surround information, so be sure to check your DVD packaging to find out for sure.
