14 DAY TRIAL // Most music you listen is MP3, so what does a MP3 do?
MP3 is a system which allows compressing and cutting digitally a sound till 90 % of its size with almost not any quality loss.
In other words, if a song occupies 100 MB, in MP3 form it will require only 10.
The human ear feels only what's between 5 Hz (sound measurement unity) and roughly 20 kHz.
The MP3 constrictor first eliminates the frequencies lying under 2-5 Hz and cuts most of those over 16 kHz.
After that , it will cut feeble sounds which are not heard because they are "covered" by sounds of greater volume.
After eliminating the inaudible sounds, the signal is compressed by ejecting the redundancies and repetitions left by the first processes.
The base is a filter that relies on the human ear's limitations to discard the sounds we do not really hear, even if they are present on the record.
The origins of MP3 are very recent: in 1989 the Fraunhofer Institute (Germany) patented after three years of research the invention.
A programmer named Tomislav Uzelac developed in 1997 the first MP3 reproducing software, called AMP.
The revolution arrived two years later, when Napster was created and with it, the free interchange of these files through Internet.
How do you make a MP3?
A music disk can be copied by programs like AudioCatalyst or CDex, which transform the signal in order to be understood by the computer.
With the same program or others (like MusicMatch Jukebox), the signal is compressed until the desired quality/size level is reached.
To listen on your computer MP3s, you just need a reading program, like Winamp, RealPlayer or Sonique, which can be achieved freely from the Internet.
The reduced size of MP3 archives facilitates their distribution by Internet and in whatever cases one might need to carry or share audio information in a short amount of time and with less effort.
Everybody can put in a digital format his/her original disks, but the legal problem appears when these archives are distributed to others: possessing them is legal; distributing them contradicts the copyright and the laws of intellectual property.