This MP3-PC connection is possible in the first place thanks to continuingimprovements in disk drives. A 16-gigabyte hard drive can now be bought,astonishingly, for less than $180. Each gigabyte can hold between 12 and 24hours' worth of MP3s, depending on how they are created. The first MP3 rule:Not all MP3s are created equal. On the surface, MP3 "ripping" programs allwork essentially the same way. You put a music CD into the CD-ROM on yourPC, run the program and sit back as it converts each song track into an MP3file.

The encoders in the various MP3 programs, however, have strikinglydifferent quality levels. Audiophiles like Matt Fellers, a golden-earedengineer at the San Francisco headquarters of Dolby Laboratories Inc., saythe clearest, brightest sounds are produced by the encoder made byFraunhofer, the German research outfit that invented MP3s. The encoder isavailable for $50 from www.opticom.de. A faster version is expected to beavailable soon in the popular MP3 software made by MusicMatch Inc. of SanDiego.

Unlike with the encoders, engineers say, there is no substantial difference,at least in sound quality, among the many different MP3 players. Pick theone that looks the prettiest. You can pick one to download from any of thebig MP3 music sites.

The second rule: MP3s are like videotape; the faster you run them, thebetter the quality. Most MP3 software lets you adjust the "bit rate" of anencoding to anywhere from 96 kilobits to 250 kilobits a second. (The typicalInternet MP3 is encoded at 128 kilobits.) Of course, the higher the bitrate, the bigger the file; a 192-kilobit MP3 takes up 50% more space than a128-kilobit MP3.

All audiophiles, and many other careful listeners, can hear the differencebetween a 128-kilobit and a 192-kilobit file. A higher bit rate can make upfor differences in encoding, too. For example, an MP3 made at 192 kilobitswith the Xing encoder, available in the popular AudioCatalyst package, willsound better than a Fraunhofer MP3 made at 128 kilobits. But there's nopoint in going any higher than 192 kilobits. In fact, 160 kilobits should befine.

People planning on playing their MP3s on portable devices should be mindfulof file size. These players can't yet hold a lot of data. But for everyoneelse, it makes sense not to skimp on sound quality. Drives are gettingbigger almost daily.

Hang on to your CDs, though, until you see what's coming down the road. New,post-MP3 encoding systems are expected to hit the market in coming months.Their principal advantage will be that they will encode music in smallerfiles than MP3s.

Finally, howdo you get the sound out of your PC? Here again, there are good,better and best approaches. The simplest method is to play your MP3 filesthrough your PC speakers. But most people will want to take advantage oftheir home stereo systems, which you can link to your PC via one of theaudio output jacks on your PC or sound card.

You should buy the best sound card you can afford; the Diamond andSoundBlaster devices are favorites. To minimize distortion, usewell-shielded cables, and keep them as separate as possible from the mess ofother wires that are probably hanging out of the back of your PC. (Have asound cable cross an electrical cable at a right angle, rather than runparallel to it.) For the best sound, turn the audio signal up all the way onyour PC, then adjust the actual volume with your stereo.

Many audiophiles won't like this approach because the electrical engineeringinside of PCs can't compare acoustically to what's inside a good stereodevice.

When I tried it, I was picking up all manner of hum and buzz on my stereo.So for optimal sound, you'll want to use a specialized audio unit called adigital-to-audio converter, rather than your PC, to change your digital bitsinto analog sound.

These converters are available from most high-end audio stores. Likeanything in the audiophile world, they can cost anywhere from $100 to theprice of a small island. I have been very happy with the $180 Gamma unitfrom California Audio Labs. You'll also need to make sure that you can run adigital, rather than analog, connection from your PC to the converter box.The $180 SoundBlaster Live card has what's called an S/PDIF jack that ismade precisely for this purpose.

Once you start down this path, you may start fantasizing about the next bigdigital toy: a home-networking system that connects all your machines.

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