Small, Powerful Audio Players

The latest generation of portable audio players offer interesting new features and more storage, and the best of them deliver excellent sound quality. The highest-capacity player we've tested recently is the 80GB Apple iPod, which can store around 20,000 popular songs of average length and compression level. The Microsoft Zune has a neat new wireless sharing feature, and the SanDisk Sansa e260R integrates easily with the Real Rhapsody online music service. Many models appear similar at first glance. We point out differences in features and performance to help you weigh which is the right player for you.

Sound-Quality Tests

The PC World Test Center conducted sound-quality tests on the 21 players we reviewed for this story, using an ATS-2 analyzer provided by Audio Precision, a maker of audio test and measurement equipment. The first test assessed the output level each device could attain before reaching 1 percent distortion, generally regarded as an acceptable threshold. A second test determined the frequency response using 30 tones ranging from 20 Hz to 20 kHz. The lab also measured crosstalk (how much the left and right channels blend, thereby narrowing the stereo field), signal-to-noise ratio, and total harmonic distortion. Obviously, the less distortion and noise an audio player creates, the better it sounds.

In our tests, the hard-drive-based players tended to deliver better audio quality than the flash-based models did. A top-performing flash player such as the iPod Nano, however, offers better sound quality than many hard-drive models do.

Online Stores

To buy music, owners of Apple iPods must shop at the iTunes Store, which supports only AAC-encoded files. But owners of devices that support the PlaysForSure digital rights management system (which uses the WMA format) can select from a range of stores such as Napster, Urge, Wal-Mart, and Yahoo Music Unlimited. Notably missing from the list of players compatible with PlaysForSure, oddly, is Microsoft's Zune, which doesn't support PlaysForSure and works only with the Zune Marketplace DRM system.