Bit Rate

Compression of audio data using the MP3 method reduces the data volume corresponding to the selected target quality to a fraction of the original volume. A decisive factor governing the music quality of an MP3 file is the data transmission rate - referred to as the bit rate. In connection with MP3, the bit rate is measured in kiloBits per second. The higher the bit rate, the higher the quality of the result. However, this also increases the size of the data volume to be stored.

There are both fixed and variable bit rates which, however, are not supported by all MP3 players. The traditional method of audio coding CBR (Constant Bit Rate) maintains a constant bit rate during the entire recording. In connection with the variable bit rate method (VBR), the bit rate drops to a lower level when a section in a song contains little sound information. As a result, the bit rate is frequently reduced to 32 kBit/s or less. In sections with large quantities of sound information, the bit rate increases to a specified maximum which is normally at 128 or 192 kBit/s. The advantage of the variable bit rate is an overall better sound quality with reduced file sizes.

While MP3 is better suited for coding at higher bit rates, the WMA format (Windows Media Audio) is appropriate for lower bit rates. When using WMA format, even recordings with a bit rate of only 64 kBit/s sound acceptable. The data loss at a constant bit rate is less noticeable than in an MP3 file. However, outstanding bass reproduction at 64 kBit/s cannot be achieved in any format. WMA is much better suited than MP3 for ultralow bit rates (e.g. 16 kBit/s).