Choosing the Right Bitrate
The type of compression you choose obviously affects audio quality, but so does the amount of compression. This is measured in terms of bitrate; the higher the bitrate, the more bits are included in the digital file, and the better the sound quality. Of course, the more bits in a file, the larger that file is, so a higher-bitrate recording is going to take up more storage space than one at a lower bitrate. For example, a file ripped at 192Kbps will sound better than one ripped at 128 Kbps.
Now, bitrate is factor only if you choose a file format with lossy compression. Lossless compression reproduces the original recording exactly, so bitrate isn’t really an option. All of the major lossy compression formats, however, enable encoding at different bitrates.
You can select the bitrate used when ripping music from CD. In addition, different digital download and streaming sites offer tracks at different bitrates. The iTunes Store, for example, offers its tracks at 256Kbps, as does the Amazon MP3 Music Store. The free version of the Spotify music service, however, streams audio at 160Kbps, while the paid Premium version streams at 320Kbps.
But wait, there’s more – in the form of variable bitrate encoding. In contrast to standard compression, which uses a constant bitrate from start to finish, variable bitrate compression varies the amount of data encoded throughout the course of a recording, using a lower bitrate when there’s less complex audio content and a higher bitrate with the content is more complex. The result is, theoretically at least, a better sounding recording that takes up slightly more space than one with constant bitrate encoding, but still less than with a comparable lossless format.
Bottom line, if you want better sounding playback, go with a higher bitrate or variable bitrate. If you need to conserve on storage space, choose a lower bitrate. Again, a compromise is necessary.