I’ll admit I don’t know everything there is to know about television. But I know there is a radio signal for the audio, and a radio signal for the video portion of the broadcast. High-definition television will send a different video signal (if it ever gets off the ground–I haven’t heard much of HDTV lately). But what will become of the old audio signal? Will it remain the same? I have a little stake in it staying the same, because we have a hand-held radio that receives only the audio signal. And it was a Godsend during the recent blackout.
Sorry, but HDTV systems will use some form of digital compression to transmit audio, such as MP3, MPEG 1 Layer II, MPEG 2 BC, Dolby AC-3, or MPEG 2/4 AAC. The latter 3 allow for multi-channel audio (5 or 6 channels), which is a more fitting companion to high-quality digital videos.
I don’t have details of the exact standards in use, but I believe most systems are planning to use some variation of MPEG 2 (which has 2 separate audio coding standards, BC and AAC), which is already used in Japan. The US is planning to use Dolby AC-3 digital audio according to this source. These audio signals will not be able to be decoded by a normal radio.
