Moving Picture Experts Group-1 Audio Layer 3 or MP3 as it is commonly known is a form of audio media compression.

Digital music uses numbers to represent an analog audio waveform, which takes up a lot of space. When we rip a CD to our computer, we are bringing in an exact replica of the CD’s contents. This means using up a lot of space on our Hard drives etc.

The purpose of the MP3 is to compress a sound file for the ease of portability or transferability. When dealing with MP3 encoding, we are dealing with low frequency or auditory “masking“. This is when the MP3 algorithm uses psychoacoustics to take away frequencies that lie outside of the human hearing range, since humans can’t hear them anyway. This is also known as lossy compression, the removal of unnecessary bits that deal with the reduction of volume [removed]Amplititude).

By stripping away the low frequencies, which is needed for a proper balance of the audio file the amount of high frequencies(loudness) increases. In a stereo audio file the MP3 algorithm also removes redundant data, since the same data is duplicated on each channel.

When performing lossy audio encoding, as in the creation of an MP3 file, the creator is allowed to set a bit rate, which specifies how many kilobits the file may use per second of audio. When a lower bit rate is used it provides a relatively lower audio quality as it produces a smaller file size. Files encoded with a lower bit rate will normally play back at a lower quality.

The increase in loudness may be evident when playing an MP3 file on a car stereo or CD Player, for example. Most often there will be distortion though it may be subtle. CD and other audio players have a maximum output level, defined by the manufacturer and CD standard. Distortion occurs when the output level of the MP3 goes beyond the maximum level of the playback device. The output level of playback devices can vary.

For most people the standard MP3 encoding would be fine, but for the ones with sensitive hearing it will affect their appreciation for the song.

For the discerning music listener, one way to get around this problem would be to:

             – Convert song to a wave file

             – Lower the master output level approx. 1 dB for headroom (this so when it is converted to MP3 format there is no peak or clipping, which could lead to distortion)

            – Re-burn the audio file

            – Convert the audio file back to MP3 (using a bit rate 196 or higher)

This extra step might very well be worth the while for a better enjoyment of the music.