Digital Sound: The next wave will be high definition
So you’re feeling techno-trendy with your progressive-scan DVD player and your six-speaker, surround-sound home theater system. Better keep your eye on some increasingly popular digital music formats. Lumped together as high-definition audio, or HD audio, the new formats are doing for music what high-definition TV is doing for television—recording it in greater detail and playing it back at a higher fidelity, or in a more lifelike way. HD audio formats allow music to be recorded and played on the multiple channels of surround-sound systems such as Dolby Digital 5.1, which has six channels, compared with the two channels, of traditional CD stereo recordings.
Surround-sound systems add rear speakers and a center channel to a stereo system. “Think about being in a concert hall. You hear the music directly from the instruments, but you also hear a lot of reflections. The wood and other surfaces in the hall are designed to reflect the sound. It gives the music an immersive quality. With HD surround, you can re-create those reflections,” says Peter Otto, technical director of the Department of Music at the University of California at San Diego.
Two Main Competitors
The two main HD audio competitors are DVD-Audio and Super Audio CD. Intel is working on a third format that would be used on PCs. DVD-Audio uses the same type of disc as DVD-Video, but it stores high-resolution audio files instead of video ones. DVD-Audio files are higher quality than the sound files on a DVD movie, which are CD quality. DVD-Audio was developed by a DVD industry consortium. Super Audio CD, or SACD, was developed by Sony and Philips. The format stores high-resolution sound on CDs. Both formats are capable of performing better than the two-decades-old CD format, although they don’t always live up to their potential, says John Atkinson, editor of Stereophile magazine. “Both can produce very high-quality audio when done right,” he says.
Unfortunately, lax recording techniques can negate the technical advantages of the new formats, Atkinson says. “A very well produced CD can sound better than a poorly produced SACD or DVD-Audio recording,” Atkinson says.
Manufacturers Play Both Sides
The rivalry between DVD-Audio and SACD already has sparked debate among sound engineers and amateur audiophiles. Some see the competition as the latest sequel to the Sony Betamax vs. VHS war, with the loser eventually disappearing. There is one significant difference in this battle: Some manufacturers are making universal high-definition audio players that will play both formats, along with DVD-Video. Consumers with a universal player will be able to buy recordings in either format, so some experts think both can survive.
Initially, SACD was a stereo format, meaning it was designed to be played over two speakers. Music fans will need to buy a multichannel SACD player—which can cost more than $500—if they want to experience the surround-sound capabilities. Some SACD discs can be played on ordinary CD players. Those discs have two layers: one SACD layer and one standard CD layer. The discs will produce CD-quality sound when played on ordinary CD players. DVD-Audio discs typically will play on several types of players. The discs contain a Dolby Digital track that will produce CD-quality sound when played on a standard DVD player. It will yield surround-sound if played through a surround-sound receiver. The discs also include a high-resolution stereo track that will play only on DVD-Audio players. A final, high-resolution surround-sound track will produce the full effect when played on DVD-Audio players connected to surround-sound systems.
A Win for Music Lovers
Most music lovers will experience a significant improvement over CDs with either SACD or DVD-Audio, if they are connected to a high-performance system, Otto says. “Your typical, $200 home-theater-in-a-box isn’t going to give you a true DVD-Audio experience,” he says. “With a good system and good speakers, you should hear a lifelike difference.”
In a year or so, notes Instat-MDR market research analyst Gerry Kaufhold, a new generation of computers will support HD audio and give further momentum to the higher-resolution sound formats.