What is MP3 Technology?

The ubiquitous cheap MP3 player has become such an integral part of our daily lives that we hardly notice it anymore! A few years ago, you would see someone with a pair of headphones, bopping to some stream of music flowing into his or her ear and we half-smiled with a mixture of amusement, pity and ridicule. Now, as we sit in our plane seat with our Bose noise canceling headphones hooked to our iPOD, we wonder how the person sitting next to us could ever choose to fly without an MP3 player. Read a book instead?? Why??

So what is this MP3 technology that has the world of consumer personal electronics abuz? If you stick in a music CD into the drive in your computer and look at its contents, you will find that each music track is stored as a separate digital file, typically in the .WAV format. Each file is about 50 to 60 megabytes in size. So a typical CD has between 12 and 14 tracks or digital files. Each file is that long because the song or track is recorded in multiple channels. It turns out that most music tracks are recorded in greater definition that can really be perceived by the human ear. The human ear has its limitations when it comes to hearing music and other sounds. For example, if two tones of equal intensity but different pitch are played simultaneously, the human hear will hear the lower of the two notes and almost completely ignore the high note. Scientists have been able to create mathematical models that completely describe auditory perception of the normal human ear.

MP3 encoders today take a digital file and process the signal using the auditory models created a couple of decades ago. These encoders strip the extraneous audio signals, leaving in place only those portions of the signal that can be heard by the human ear. The resulting MP3 track is much smaller in size - typically about one-tenth the size of the original digital file. This compression is achieved will no significant loss of sound quality. With this compression process, a CD that normally held 12 to 14 tracks, can now hold nearly 150 tracks in the MP3 format!