Just when you got used to DVD Audio and SACD, along comes this new DualDisc. The new media is, in essence, a CD and DVD combined in one slightly thicker disc. The CD side is the music album-only, and the DVD side can contain many features - videos, 5.1 surround sound, high- resolution stereo and surround found on DVD Audio, interviews, etc. Just about anything that is found on a DVD these days can be put on a DualDisc. From a market standpoint, DualDisc seems poised to replace DVD Audio and challenge SACD by delivering the high-resolution PCM tracks in a machine that also can play both the CD tracks and video, the mega-available DVD Video player. But is the new format good for high-res? First, a little background. The technical spec allows DualDisc DVD side audio tracks to be authored in several forms. The DVD Video section allows compressed Dolby Digital stereo/5.1 surround or 16-bit/24-bit linear PCM at 48 kHz or 96 kHz sampling. These audio tracks are essentially the same kinds of audio that can be put on a DVD Video and, in fact, the audio is stored in the Video TS folder on the disc, just like a regular DVD.

ADDING DVD

Unlike the regular DVD Video, the DualDisc also allows the DVD side to add the high- resolution audio contained in DVD Audios, a separate DVD format. Thus, the DualDisc can include up to 24-bit, 96 kHz LPCM surround recordings and up to 24-bit, 192 kHz stereo audio. These tracks are contained in the Audio TS folder, which is essentially the DVD Audio section.

With DualDiscs, the problem for us high-res proponents is that the labels do not do a good enough job defining or explaining the access to the DVD side audio. For instance, when I went out and bought several discs, I saw that the DD box notes on many indicated that the DVD side had "enhanced" stereo audio. I assumed that these discs contained higher-bit and highersampling rate audio like a DVD-A.

I soon discovered that was not the case. On the reissue of Oasis Definitely Maybe, the promo sticker said the DVD side had "all 11 songs in enhanced stereo." I popped it into my Esoteric DV-50 expecting to see a 24-bit, 96 kHz audio, but my digital audio info meter said the recordings were 16-bit, 48 kHz. Enhanced by the extra 4 kHz of sampling rate, I suppose, but not much, if any, of an audible improvement over the CD tracks.

The Toby Keith's Shock and Y'all DualDisc did contain information on the case label that said the disc included "advanced resolution audio tracks" and indicated what the word length and sample rates were (24- bit, 96 kHz MLP PCM stereo).

The Keith DualDisc case notes also stated those tracks were contained in the DVD Audio section of DVD side, but nowhere did the notes say that the "advanced resolution" tracks could only played by DVD-A player. The only clue was a small, fine print section that said: "Special Features available on DVD Video/Audio Players: High Resolution Surround/Stereo." Those who want to access the high-res tracks with their DVD Video-only players are out of luck. They have to listen to the Dolby Digital.

LABEL CHALLENGE

If labels were a bit daring, gasp, they could add linear PCM 24-bit, 96 kHz stereo tracks to the DVD Video section, so those who don't have a DVD Audio player could experience the advanced audio tracks. The DVD Video stereo audio standard allows for either 16-bit/48 kHz or 24-bit/96 kHz linear PCM, but few labels have ever taken advantage of the option.

DualDiscs also have other issues. The slight thickness increase over a CD means that many car players and some slot-loading computers may not mount them or read the TOCs. Mine tested out fine in a variety of players, though my Powerbook G4 slot loader DVD drive groaned when trying to pull in the disc.

Although I have mixed feelings about DualDiscs as another unmandated format thrown into the audio delivery business and the labels' nonstandardized box label terminology relating to advanced audio tracks, I am warming to them. After all, they can deliver high-resolution music. Since DVD-A seemed to be stagnating, and Internet-delivered, high- resolution audio is off in the distance, the DualDisc is likely the interim savior for high-bit, high sampling PCM.

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