OTHER TECH

Portable MP3 players have gone from novelty to staple item in four short years. But with popularity has come proliferation, and many MP3 players aren't just MP3 players anymore. A growing number play files encoded in the Windows Media Audio (WMA) and Advanced Audio Coding (AAC) formats as well, and the storage options are many. Some players rely on fixed memory, others use removable memory cards, and still others include both. Removable memory can come in many forms, including Secure Digital (SD), Memory Stick, CompactFlash (CF), SmartMedia, and MultiMediaCards (MMC). And some players, like Apple's trendsetting iPod, eschew solid-state memory for high-capacity, miniaturized hard drives.

Since the options are many, the confusion can be great-which is why we've put together this little guide. Whether you're contemplating your first plunge into the world of MP3, considering buying a player as a gift, or trying to bring yourself up to date after buying one of the first players several years ago, you'll probably want some help sifting through the possibilities.

The State of the Art

Portable players continue to be most strongly associated with MP3, which gained notoriety as the great facilitator of song sharing over the Internet, and every portable in our listings will play MP3 files. But given the considerable clout of Microsoft, which is pushing WMA, about half of them also play WMA files.

Most portables continue to rely on flash-memory storage, although hard-drive players are gaining in popularity. Flash-memory cards or chips can easily be rewritten, but a 64-megabyte (MB) one can't hold more than about an hour of music when encoded at a bit rate that provides decent sound quality-say, 128 kilobits per second (kbps). Hard drives, on the other hand, offer much more storage at much lower cost. And, since a CD can also hold a tremendous number of compressed audio files, many portable and home CD players now include playback for MP3 and sometimes other Internet-friendly formats. (CD players aren't included in the listings here, nor are MiniDisc players.) Now let's take a look at these issues in a little more detail.

The Big Squeeze

Pay no attention to that algorithm behind the curtain-the one that does the seeming impossible by squeezing high-fidelity audio bitstreams down to a fraction of their original size without turning the sound into mush. MP3, WMA, AAC, and RealAudio are all perceptual coders, or codecs. Because of the way our ears work, we can't hear the weaker of two tones if they occur very close to each other in frequency and time. And the closer the spacing, the smaller the difference has to be for the softer one to be masked by the louder one. (Think of how everyone at a party has to talk louder to be heard as more people arrive.) Codecs use models of human hearing to determine what parts of a complex sound can be eliminated without degrading the audio quality.

You'd think that removing information from a signal would have to make it sound worse. But that isn't the case if you remove only what would've been masked anyway. Consider a fly buzzing next to a jet engine. Would you hear any difference if the fly was removed? A good codec will do an excellent job of compressing signals as long as you don't reduce the data too much. But a higher data rate doesn't necessarily equal better sound. It depends on the codec. Some schemes can give you quality equal to or better than the others at lower data rates. This is one area where competitors have tried to draw attention to themselves in the face of the MP3 juggernaut.

Who's Minding the Storage?

Most portable compressed-audio players store files on embedded flash memory or removable cards. Flash memory is attractive because it's nonvolatile-which means the stored data can't be lost unless you deliberately erase it. It's also very compact and impervious to shock. So, unlike a portable CD player, a solid-state player doesn't need a complicated memory-backup system to deal with the jolts and vigorous motion of jogging or traveling.

But flash memory can be expensive. Creative Labs' Nomad MuVo, for instance, is one of the smallest MP3 players you can buy, but it can hold only a fraction as much music as the same company's hard-drive Nomad Jukebox. And the smallest Jukebox is only $80 more expensive-but 2 inches wider, 3 1/2 inches longer, an inch thicker, and 14 ounces heavier. If you like to listen to a wide variety of music and don't want to have to be frequently downloading new tunes into the player, go with a hard-drive player. If you can get all of your favorites into an hour or two of playback time and want the smallest possible player, go with flash memory.

Because of the expense, you won't be buying flash-memory cards the way you might buy blank CD-Rs, which are not only much cheaper but hold a lot more data. For example, 32-MB MultiMediaCards sell for around $35, 64-MB SmartMedia cards for around $50, and 128-MB CompactFlash cards for around $80. (You can get about a minute of music per megabyte at the 128-kbps rate.) While flash memory has gotten a lot cheaper over the past year and a half, it's not likely to hit the pennies-per-megabyte level of hard drives and removable discs. And none of the competing flash-memory formats are compatible with any of the others. Once you buy a Memory Stick player, for instance, you can only use Memory Stick cards in it.

Players with portable hard drives start at about 5 gigabytes (GB) in capacity but typically have 10 GB or more. With so much storage space to play with, you can not only download considerably more tunes than you can to a flash-memory player, but you can also use a higher bit rate to improve sound quality.

Of course, you can put any kind of data, including compressed music files, on CD-Rs, which are easy to find, dirt cheap, and hold 650 MB apiece. You can't play compressed-audio CD-Rs on just any old portable CD player, but more and more models are compatible with MP3 and the other formats. If you want to burn your own discs, though, make sure your computer can write CDs, not just read them.

And then there's DataPlay. This new format comes on micro-optical discs about the size of a half dollar and can hold about 500 MB, or about three-quarters as much as a CD. Many people could carry their entire CD collections in their pockets by compressing the music and transferring it to DataPlay discs, which use the QDX codec.

Kicking the Tires

Once you've decided whether you're going to go with a hard drive or flash memory, you'll want to check out the particular player features. Is memory built into the player, and if so, how much? (You might not need a removable card if enough memory is onboard.) Since these are portables, you'll want to consider size, weight, and playing time on one battery charge or load. Also check out whether the batteries are removable, and if the standard battery is rechargeable, whether you can use ordinary AAA or AA batteries in a pinch. Does the player include headphones or earbuds? If headphones, how sturdy are they? Does it have an FM radio? Some people will want a built-in microphone for dictation.

Check out the inputs and outputs. All portable players except Apple's iPod have USB connections, and a few have both USB and FireWire ports. A stereo analog input generally means you can rip to MP3 directly from your music system or a portable CD player. Also consider the compatibility of the supplied ripping and transfer software. Make sure the player will work with your computer. If you own a Mac, you won't want to open the box and find that the software runs only on PCs. Even Windows users might hit the occasional snag, like software that won't run under their version of the operating system. Finally, note which compressed audio formats a player can handle beyond MP3 and whether you can upgrade its internal software to support future formats or to fix problems and enhance features.

You are now armed with all the basic information you need to scan through our product listings and draft your portable-player wish list. While having so many options to choose from can cause confusion, they also create possibilities. The chances are good that a little careful research will lead you to a player with just the right combination of performance and features. And whether you're buying it for yourself or someone else, getting to play with all the latest high-tech toys while you're out shopping can be half the fun.

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