There really is a successor to the Compact Disc. But is it the Super Audio? Is it DVD-Audio? Or is it...something else?

The mainstream consumer electronics press, the one that has always said all amplifiers sound alike, is in a bit of an embarrassing situation. When you've so long praised the Compact Disc as being as perfect a source as we will ever need, how do you then justify saying good things about a higher-definition disc? Can we actually improve on perfection?
     We, of course, have no such problem, because we've always said that -- although 16 bits and a 44.1 kHz sampling rate are way better than we had dared to hope -- we need more. And now we've got it, with a new high-definition system.
     Make that high-definition systems. SACD and DVD-Audio, like Beta and VHS before them, are headed for a showdown in the marketplace. As the poster for a famous slasher film says, "Who will survive, and what will be left of them?"
     We've heard both systems, we might add, and it's easy to hear that either system is way better than the Red Book CD. What we have not been able to do is hear the same material on the two systems, and it's possible we never will, since record companies appear to be taking sides, choosing one system or the other.
     Most of them are choosing SACD for a good reason: it was first to market, and there are actually players in people's homes. Nearly all of these players are from Sony, co-developer of SACD, which launched its original SCD-1 in December 1999, a full year before DVD-Audio. Its co-developer, Philips, introduced its first SACD player only 13 months later. In the meantime, Sony, which is after all a major record producer, has not done what we had expected, namely flood the market with software. Indeed, most of the software we've seen is from audiophile companies, such as Opus 3, First Impressions Music, and Chesky. From the illustration above you'll see that Chesky is one of the few companies hedging its bets. Sort of...more on this in a moment.
     Which of the two systems will win? The answer is crucial, because guessing wrong can mean getting stuck. SACD is backward compatible, in the sense that the players can play conventional CD's, and the discs have a Red Book layer than can play on conventional CD players...but then you'd be back to the low-definition standard. DVD-Audio players also play CD's, but the discs will play only on special DVD-Audio players. Or, if the producer chooses, on DVD video players as well.

Super Audio
     Though SACD discs don't bear the familiar DVD mark (which is licensed exclusively by the DVD Forum), this is physically a DVD, though its encoding is totally different from that of any other DVD. Super Audio is tightly allied to Sony's own Direct Stream Digital (DSD) recording system, which the company has been offering for both professional recording and archiving analog masters. DSD is quite different from the Pulse Code Modulation (PCM) used for conventional digital recording.
     Instead of taking samples at precise times determined by a clock, the DSD system monitors the waveform as it arrives. If the level is higher than that of the previous sample, it generates the binary digit one. Otherwise it generates a zero. Silence is represented by alternating ones and zeros.

Sony likes to say that (as shown in the diagram above) the bitstream is analog-like, and indeed the analog signal can be recovered (in crude form) with a single capacitor to filter the highs. Critics -- including UHF -- have noted that the diagram has been "arranged" to look good.
     That said, DSD is capable of storing far more information than the standard Red Book CD. Not surprisingly, then, in direct comparisons it sounds way superior to CD. And if it were the only show in town, we would be urging you to go ahead and buy it. But...

DVD-Audio
     Two years ago, several companies brought out high resolution (24 bit, 96 kHz sampling) DVD's that could be played on standard DVD players. The tracks were placed in what the DVD Forum calls the "video space," the part normally reserved for movies. DVD players do have 24/96 decoding. Unfortunately, they are uniformly weak as audio players, no matter how much data they're given. We were eagerly awaiting the "real" DVD-Audio. The system was delayed by an unrelated event: a software tool for circumventing the DVD's anti-piracy code was widely circulated on the Internet.
     Now it's out, with several DVD video players offering DVD-A playback as a bonus. Software remains sparse. Worse, the players have no way to get the digital DVD-A data into an external decoder decoder. Smart? Adding 5.1-channel DVD-A to most A/V systems may be impossible unless you replug everything.
     Super Audio's long lead convinced a number of record companies to bet on that horse. There's a Chesky DVD-A on the previous page, but it isn't quite standard. It is a six channel disc, which uses the ".1" subwoofer channel as a full-fledged channel, with speakers placed left and right front, left and right upper sides, and left and right rear. The demo is convincing, but who will set up a system for (so far) one disc?
     DVD Forum took time setting the DVD-A standard, because it has over 230 member companies (as opposed to just two in the SACD camp). The resulting standard has something for everyone, with not one but multiple standards. Sampling rates can be anywhere from 44.1 kHz to a whopping 192 kHz, with either 20 or 24 bits. The number of channels can number 2, 4, 4.1, 5, 5.1 or 6. And thanks to compression, a two-channel 24/96 recording can run nearly four hours! On the other hand, adding an alternative 5.1 channel version cuts running time to the 74 minutes of the CD.
     DVD-A does not include a Red Book CD later, as SACD does, but it's possible to place a compressed copy of the audio in the disc's video space, where it can be read by any DVD video player.
     DVD-A's most controversial aspect is a measure to counter piracy: the addition of a digital "watermark" to the music. The watermark, it is said, will survive even reconversion to analog, and will permit the identification of pirated material. The first discs don't have the watermark, and they sound very good. But some audio people who attended demos of the watermarking system were horrified by the result...whereas others reported that the demos were so poor they couldn't tell.
     For the moment, both systems sound good, better than CD. But one of them is likely to leave its early adopters high and dry.

(To read the full range of articles from our print issue, just order issue 61 at our secure server.)

Complete articles from this issue:
The Battle of the Super Discs, Cambridge Isomagic Converter, Soundcare Superspikes, State of the Art

Excerpted articles from this issue:
New Surround Formats, Defeating DVD Zoning, Vegas 2001, Audiomat Tempo & Vecteur D-2, Audio Refinement Pre 5 Preamp, Osborn Mini Tower Speakers, Mirage OM-9 Speakers