MP3 has changed the way people listen to music on the Internet. It
wasn't so long ago that the average pop song converted into a WAV file
would have taken hours to download using a 28.8kbs modem connection and
required up around 50 megabytes of disc space. With the same song
converted into an MP3 file, the download time and file size are reduced
dramatically to around one-tenth the original size while sounding just
as good as before. MP3 is a form of compression. It's an acronym which
stands for Mpeg 1 Audio Layer 3.
MP3 compression is based on a psycho-acoustic model which recognizes that the human ear cannot hear all the audio frequencies on a recording. The human hearing range is between 20Hz to 20kHz and it is most sensitive between 2 to 4kHz. When sound is compressed into an MP3 file, an attempt is made to get rid of the frequencies that can't be heard. As such, this is known as 'destructive' compression. After a file is compressed, the data that is eliminated in the creation of the MP3 cannot be replaced, but when you hear the song, your brain is deceived into thinking that the complete sound is still present.
When encoding a file into the MP3 format, different compression levels can be used. For instance, an MP3 file created with 128kbps compression will be of a greater quality and larger file size than when using 56kbps compression. The more the file is compressed (to a lower kbps figure) the more the sound quality is reduced. Ultimately, the benefits of MP3 compression mean that people can back up their music collection onto hard disc or burn their own music selections onto CDs which can hold over 100 songs.
Some Roberts radios are able to playback MP3 files which means that you can not only play your music collection on your PC - you can also play it through the radio speakers by inserting an SD card with your files into the machine, by playing these files from a CD written using your computer, or by streaming the files directly from your computer using one of our Internet Radios.
