Portable MP3 Players
The Samsung Mini Yepp, shown here in its actual size, is one of the smallest portable MP3 players on the market.
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A file that you can play only on your computer is only so useful. Soon after MP3s became popular, people wanted portable MP3 players. These items are like portable cassette or CD players but use the computer memory or a tiny hard drive to hold the music. All of the players include a software application that lets you transfer MP3 files from your computer into the player.
Most of them also include functions that enable you to copy music from CDs or Web sites and create custom play lists.
An MP3 player's job is pretty straightforward. It's really a mini-computer built only to handle MP3 files. When you play a song, the player must:
- Pull the song from the memory, byte by byte
- Decompress (expand) the compressed MP3 file
- Run the decompressed bytes through a digital-to- analog converter to change them back into sound waves
- Make the analog signal louder so you can hear it
The portable MP3 player connects to your computer's USB port or parallel port to transfer data, and the MP3 files are saved in the player's memory. The microprocessor, which functions as the player's "brain" interprets the user's directions. It then shows information about the current song on the liquid crystal display (LCD) panel and sends the directions on to the digital signal processor (DSP) chip.
The MP3 version of a song does not sound exactly the same as the original CD because some of it has been removed, but it's so close that you probably can't hear the difference. In fact, your brain blends certain sounds together, making them seem more like the original than they actually are.
Here's a cool experiment that shows how your senses can trick you. Look at the image on the right. Do you see a square inside another square? Now, put your fingers over the four stars. What happened to the second square? Like your eyes, your ears can play tricks on you, too!
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