The guys over at Shop Sansa have written another great article about mp3 players, this time on audio bitrates and compression.
Whether you are purchasing your music online or copying from your own personal CDs, records or tapes, there are three things to keep in mind – the bitrate, the storage capacity of your Digital MP3 player, and the playback quality of your player and headphones.
What is a bitrate?
The bitrate is the average amount of data required per second of music. This determines the audio resolution of an MP3 music file. The higher the number of kilobytes per second (kbit/s), the closer in sound quality the MP3 is to the original source - and the larger the file size. The bitrate you use when compressing your Digital MP3 player files depends on the quality you want and the space you have to store it. An MP3 digital file created using the mid-range bitrate setting of 138 kbit/s creates a file that is about 1/10th the size of the original CD.
When compressing audio, the extremely high and low frequencies get discarded — even with just minimal compression. Although considered inaudible, these frequencies reinforce harmonic frequencies that “shade” the sound, giving it fullness and presence. The more you compress, the more you diminish the differences between loud and soft passages and this may decrease the music’s dramatic impact. Extreme compression - down to 64 kbps and lower — can completely flatten the music, making it harsh and muddy. By contrast, MP3 files of 192 kbps, 256 kbps or greater preserve most of the sonic information of the original WAV file. Acoustic instruments tend to keep their natural warmth at these resolutions, and electronic instruments sound fuller while retaining their punch.
Digital MP3 player bitrates provide the following quality results:
- 32 kbit/s is equal to medium wave of AM qualify
- 96 kbit/s is equal to FM quality
- 128-160 kbit/s is the standard bitrate most often used for its quality relative to file size.
- 192 kbit/s is digital audio broadcasting quality and is becoming the standard bitrate for MP3 music. However, not everyone has the ability to discern this difference in audio quality.
- 224-320 kbit/s – near CD quality. The audio is nearly indistinguishable for most CDs.
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