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CD players that don't hop, skip or jump

New technology is transforming the portable compact disc player from skip-prone has-been to all-terrain vehicle.

By MICHEL MARRIOTT, New York Times

© St. Petersburg Times, published April 3, 2000


Before palm-size MP3 players, before songs could be downloaded, before there was a World Wide Web from which to download them, there was portable digital music in the form of the compact disc player.

But despite the high-tech gizmos crammed inside them such as laser pickups and computerized decoders, portable CD players played music on the go about as well as an old-fashioned record player, not quite as bulky, of course, but with a similar problem: When a CD player was moved or bumped, even a little, it skipped. Listening to a CD while you jogged on a treadmill was unthinkable.

Each generation of portable CD players arrived with promises of skip-free play. Broken promises.

But no more.

Just when CD player technology appeared to be badly outclassed by ever-smaller, relatively skip-proof mini-disc and MP3 players, designers of portable CD players began striking back with better technologies.

A shining example -- literally, in its polished aluminum case -- of how portable CD players have been forced to reinvent themselves is the new anti-skip Walkman D-EJ915 from Sony Electronics.

This new model sells for $199.95, but other anti-skip Sony players with fewer features, including the D-EJ611, start at $80.

The new Walkman is handsome and almost impossibly sleek, barely larger than a 5-inch CD. It is extremely light, and its rechargeable nickel-hydride batteries have a life of 62 hours of continuous playback, more than three times that of most other players.

Portable CD players started to appear in 1984, two years after Sony and Philips Electronics jointly introduced CD technology. What makes the new Sony players stand out in an increasingly crowded field of portable CD players is their capacity to play music skip-free in almost any setting and circumstance.

At Sony's request, during a demonstration, I slapped the machine as if it were a tambourine while it played a CD. The result? Mary J. Blige belted out her songs without so much as a hiccup.

It was not surprising, then, that the results were identical under more common circumstances. I walked with the player, jogged with it and took it on a crowded subway car and a bus. Both player and listener were frequently bumped, crushed and jostled, but the music played without interruption.

A combination of technologies, grouped under the rubric G-Protection, kept the playback steady and true. The new Sony player uses a memory buffer. Long a part of high-end CD players, the buffer stores data from a spinning CD on a chip, then rapidly dips into this electronic music reservoir to cover gaps in the playback that are created when the CD is suddenly moved or bumped.

But the buffer isn't what makes these new models different. The first line of defense in the new anti-skip players are two technologies called quick focus search and fine access.

Quick focus permits the CD player to almost instantaneously regain the focus of its laser pickup when it is jarred. Sony officials say that the refocusing occurs in less than 0.3 seconds. Fine access quickly resets the laser pickup if it is bumped so it can resume reading the CDs digital music data without interruption.

The new Sony CD player also can increase the speed of the CD's rotation when it senses a bumpy ride. By spinning the disc faster, the player can more rapidly extract data from the disc to fill the player's memory buffer faster as that is needed.

Sony is hardly alone in making portable players live up to their name. Last year, Aiwa and Panasonic introduced much-improved portable CD players that were just about as skip-proof as the Sony G-Protection models. And both companies say this year they will release more refined anti-skip players.

Aiwa America plans to introduce a CD player for joggers that will feature a 48-second memory buffer -- eight seconds more than on current models -- to help it overcome skips. And like the Sony players, Aiwa anti-skip models will be able to quickly and automatically adjust the laser pickup vertically and horizontally.

Aiwa says its Electronic Anti-Shock System, or EASS Plus, does not reduce battery life. Continuous playback on the current $110 Cross Trainer XP-SP90 is 14 hours with two AA batteries. The company says the new XP-SP911 will extend battery life to 20 hours.

The XP-SP90 is not as elegant as the Sony player, but its rugged exterior is well suited for use by people engaged in athletic and outdoor activities. It also packs a big sound, to my ears significantly louder than the Sony player's.

Panasonic's new anti-skip player, the Shock Wave Metal SL-SW870, priced at $199.95, also is designed to withstand rugged outdoor use. It has a 40-second memory buffer and uses what Panasonic calls Anti-Shock Memory II, which includes a memory buffer with variable speed control for the CD, error correction chips to quickly retrack the player's laser pickup and advanced optics to rapidly refocus the laser when it is knocked out of its ideal vertical position.

The Shock Wave Metal player provides 25 hours of continuous playback on a pair of AA batteries, and it lives up to its name with a feature that trembles for youthful attention: The headphones that come with the player have a vibration unit. When a button on the player is pressed, bass signals below 50 hertz are felt as mild vibration. Officially, the feature is known as the Virtual Motion Sound System, but as Reid Sullivan, a Panasonic executive, said, "We like to call it the brain shaker."

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