But these advances come at a price. When you compress an audio file with an encoder, you lose some data irretrievably. The process also introduces a certain amount of noise -- known as artifacts -- into the audio signal. Do these changes significantly degrade the output? The answer depends on whom you ask. Many listeners swear that MP3 sounds as good as CD. Others disagree. The key question is, does it sound good enough to you?
When evaluating the quality of encoded audio, keep three factors in mind. First, consider the kind of music the file contains. Such instruments as clarinets, violins and human voices carry subtle, complex overtones that are extremely difficult to encode efficiently. Noisy pop tunes tend to survive encoding better than elegantly rendered classical music.
Also, take your hardware into account. Most PCs deliver mediocre sound at best anyway, so if that's what you are working with, you probably won't notice the shortcomings of compressed music.