Signals: A Call to Arms! (Sept. 1995)

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Back in the Seventies, when the world was a better place and Richard Nixon was President, audiophiles and videophiles were two very different groups of people. We audiophiles lovingly washed and caressed our beloved LP records, sat equidistant between a pair of loudspeakers, and closed our eyes in moments of supreme ecstasy. Videophiles, a rather suspect lot in my book, sat directly in front of their glowing picture tubes, erected huge satellite dishes in their backyards (usually in violation of local ordinances), and always kept their eyes open. We audiophiles had nothing to look at except the liner notes and were damn proud of it. But with the advent of home theater came reconciliation between the two groups, and our numbers dwindled. Some foolish people thought they could have it both ways.

Old habits die hard, and more than a little jealousy lingers. A lot of videophiles were peeved when the CD came along. “If audiophiles can step into the digital age, why can’t we?” they whined. Now those damn videophiles are smiling because video technology is on the cusp of radical improvement. Consumer digital videotape is ready for launch, and, more significant, the digital videodisc (DVD) is tantalizingly close. Two big alliances of corporate juggernauts have proposed systems that will allow full-length movies to be digitally coded on a single 5-inch disc. Videophiles, who often wear sweaters and ties, are particularly smug because the object of their greatest jealousy, the compact disc, will serve as the basis for their new toy.

The Sony/Philips Multimedia CD (MMCD), for example, provides an elevenfold increase in capacity over a regular CD, from 680 megabytes (MB) to 7.4 gigabytes (GB); that translates into

270 minutes of audio/video playing time. A model of cool optical storage technology, the disc has two data layers on one side; the reading laser focuses on one layer at a time, providing continuous play back by reading outward on one layer, then inward on the other. Using the MPEG-2 data-reduction audio/video coding algorithm, the system spins the disc at variable speeds, adjusting data rates ac cording to need. At a reference speed of 4 meters per second, the output data rate is 11.2 million bits per second (bps); in comparison, the CD rate of 1.41 million bps seems sluggish. Picture quality is said to equal or surpass that produced by the best analog laserdisc, and audio will be coded in two-channel stereo, 5.1-channel surround sound, or both.

The SD-DVD (Super Density Digital Video Disc) Alliance, to which Toshiba, Time Warner, Matsushita, RCA, and a number of other hardware and software manufacturers belong, has proposed several DVD variations, including a dual- layer disc with an even greater data capacity of 9 GB and two double-sided discs that hold 5 GB and 9 GB per side.

Understandably, we audiophiles, even those of us who have admittedly dabbled in home theater, are not happy about this development. DVD will give videophiles clear technological superiority over us. In a year or two, they will have a disc that delivers more than 4 hours of surround sound, not to mention a digital picture, while we are stuck with the CD’s measly hour or so of ordinary stereo. We don’t think that’s fair.

In fact, it isn’t fair at all. Across the land, we audiophiles are rising up and throwing aside our jewel boxes. We demand a piece of the action! We want a shot at the digital videodisc but one without video. We want all of those 7,400,000,000 bytes of storage capacity for audio, and audio alone. We want the Ultimate Compact Disc, the UCD.

For starters, we don’t think a 44.1-kHz sampling rate is good enough. Although only a minuscule amount of musical in formation lies above a half-sampling frequency of 22.05 kHz, and an even more minuscule number of us can hear above that frequency, we demand a doubled sampling frequency of 88.2 kHz.

Furthermore, we don’t like 16-bit quantization, and, if the truth be told, we never really did. Admittedly, 16-bit quantization is impressive, particularly if you express it in understandable terms: If sheets of typing paper were stacked to a height of 22 feet, a single sheet of paper would represent one quantization level in a 16-bit system. That’s great, but in a 24- bit system, the stack would tower 5,592 feet in height — over a mile high. If a single page was removed, the least significant bit would change from 1 to 0. Put another way, if the width of the North American continent was measured with 24-bit accuracy, the measurement would be accurate to within 9 inches. We believe that we need that kind of resolution to code audio signals. Besides, many digital video recorders use 8-bit coding for each of the three color signals, and if they get 24 bits, we should get 24 bits too.

So there it is. With a sampling frequency of 88.2 kHz and quantization of 24 bits, more than 4 hours of stereo could be stored on one UCD. But we’re not through making demands. We are audiophiles, after all, and we’re certainly not going to admit that we like video or even home theater, but we do kind of like the idea of 5.1 audio channels. Therefore, we want the option of storing 5.1 audio on the UCD; we figure that with 24-bit main channels and data-reduced ambience channels, you could fit 3 hours onto a disc.

Listen here, you manufacturers: While you’re a it, we’d like the UCD to be erasable, too. What? You say it can’t be done? Please. We know full well that Sony already sells a professional magneto-optical disc recorder that records 80 minutes of 20-bit, 44.1-kHz digital audio data on a 5 1/4-inch disc storing 1.3 GB. When 24-bit converters become avail able, the recorder can be configured for 24-bit recording with 65 minutes of re cording time. Sure, it sells for $40,000, but with greater volume, we think you could bring it down to $500.

We promise that development of the Ultimate Compact Disc will make us happy, and that audiophiles everywhere will not riot in the streets when you introduce the digital videodisc for videophiles. Of course, if you try to introduce some kind of 3-D television or something, you’ll be hearing from us. We’re already working on our demands describing the Super Ultimate Compact Disc. The one that will sound as good as our old LP’s.


Source: Stereo Review (09-1995) BY KEN C. POHLMANN

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