MP3 Players - The Practical Aspects

Cheap MP3 players have become extremely popular today, and are one of the mainstays of personal entertainment, especially for teens and young adults.  This popularity really stems from the practical advantages of using today’s digital music players as opposed to portable tape players or even CD players of days gone by!  So let’s delve a little bit into the practicality of these players.  If you were to stick a conventional music CD into the drive on your computer and look at the files, you will see that the files on the CD are in WAV format, and each file is around fifty megabytes in size.  So each CD holds between 12 and 15 songs.  Let’s say you are on an eight hour trans-Atlantic flight.  During your flight, you could listen to about 120 songs.  If you used conventional CDs, you would need to carry 8 to 10 discs with you.  In addition, you would likely need to carry at least 2 sets of spare batteries with you.  Put these songs into MP3 format, and you can store them on a tiny player less than two inches by two inches weighing no more than fifty grams!  And you would not need extra batteries on your flight!  Not only that, it you decided to take along a few computer files so that you can work on the flight, you could probably store them on the same MP3 player!  So the advantages of even cheap MP3 players are quite apparent.

The origin of MP3 technology can be traced back to the study of psychoacoustics.  While this is a complicated field of study, the part that is germane to this discussion is human auditory perception.  What it really boils down to is that the human ear has limitation on what tones it can perceive.  For example, with two sound notes of similar intensity but differing frequencies, the higher frequency note will mask the lower frequency note.  Scientists developed a set of mathematical equations that can fully describe the sounds that can be heard by the ear.  German scientists later developed the basis for computer software that defines and applies these equations to a standard soundtrack.  Today, commercial software (some of which is free!) is available to convert standard digital sound tracks to the MP3 format.  Although proprietary details vary, all these programs essentially take the standard sound track and strip away the parts that the human ear cannot hear.  The stripped file is then compressed further using a separate algorithm.  The resulting file is in MP3 format and is one tenth to one twelfth the size of the original file, without significant loss of sound quality.  The file can then be downloaded onto an MP3 player.  Typically, one gigabyte of memory capacity can store between 200 and 250 songs.  You would need roughly fifteen conventional music CDs to store the same number of songs!  Is it then any wonder that music CDs are on the way to becoming obsolete!