MP3 Players - The Basics

Cheap MP3 players and MP4 players have become a part of our daily lives.  Along with a cell phone, you can see the ubiquitous MP3 player on your drive to work each morning, when boarding a plane to take you to your next destination, and in cubicles next to you at work!  So what is MP3, and why has it become so popular today?  MP3 is a compressed audio format that has revolutionized the music industry over the past ten years or so.  This compression technology allows for compression of digital audio files to much more convenient and manageable sizes.  If you insert a commercial music CD into the optical drive of your computer and explore the CD, you will see that the files are often 40 to 50 Megabytes in size.  The MP3 technology that creates smaller file sizes with sound quality that is comparable to the file formats that normal music CDs use.  We have two German geniuses to thank - Thompson and Fraunhofer for helping develop the software coding needed to take a normal digital audio file, and crush it down to one tenth of its original size without a corresponding loss of audio quality.  However, the fundamental concept upon which the MP3 technology is based has its roots that go back over a hundred years, in the field of physchoacoustics.  Simply put, human hearing has perceptual limitations, called auditory masking.  Back in the mid-1890s, Mayer found that for two tones of the same intensity, the human hear was able to detect the one with the higher frequency.  In other words, the higher frequency note masked the one of a lower frequency.  More than 60 years later, and using Mayer’s work as a starting point, Richard Ehmer developed a set of equations or models to describe the various frequencies of sound that could be perceived by the human ear.

Today, there are commercial software programs that can convert conventional files from an audio CD to MP3 format.  These programs have a built in algorithm that is based on the works of Mayer and Ehmer.  The more sophisticated programs give the operator some control over the bandwidth for each of the auditory curves; the more simplistic ones do not.  To convert the file format, you need to first install the program on your computer.  Insert the audio CD in the digital drive, and select the song to convert.  The program goes to work and a few seconds later, you have a digital copy of the original song in MP3 form.  This file can then be treated like any other, and downloaded to your favorite MP3 player, or more expensive ones if you can afford them.