1. Overview of Digital audio player
1) How it works
The MP3 format has completely rewritten the rules of music distribution. It has had a huge impact on how people collect and listen to music. And with the growing popularity of Digital audio players, it is moving beyond the computer.
a) The MP3 format
The MP3 format is a compression system for music. This format helps to reduce the number of bytes in a song, without hurting the quality of the song’s sound. The goal of the MP3 format is to compress a CD-quality song by a factor of 10 to 14, without losing the CD sound quality. A 32 megabyte (MB) song on a CD compresses down to about 3 MB on MP3. This lets you download a song in minutes rather than hours, and you can store 10 to 20 songs on an MP3 player using a relatively small amount of memory.
b) Taking Your MP3 Files with You
Many people who start collecting MP3 files find that they want to listen to them in all kinds of places. Small, portable MP3 players answer this demand. These players are like portable cassette or CD players, except that they are smaller and they use solid state memory instead of a physical medium like a tape or a CD. All of the players currently on the market include a software application that lets you transfer your MP3 files into the player. Most of them also include utilities for copying music from CDs or Web sites, and the ability to create custom playlists. MPEG is the acronym for Moving Picture Experts Group. This group has developed compression systems used for video data. For example, DVD movies, HDTV broadcasts and DSS satellite systems use MPEG compression to fit video and movie data into smaller spaces. The MPEG compression system includes a subsystem to compress sound, called MPEG Audio Layer-3. We know it by its abbreviation, MP3.
Downloading MP3 files
The MP3 player is a wonderful example of a new use of existing technologies. None of the components in a typical MP3 player is radical, or even new, technology. By simply combining these components in a new way, and writing some code to control it all, manufacturers have created an entirely new line of consumer products! The job of the MP3 player is pretty straightforward. When you play a song, the player must: Pull the song from memory byte by byte Decompress the MP3 encoding Run the decompressed bytes through a digital-to-analog converter Amplify the analog signal so you can hear it. The main difference between a portable CD player and an MP3 player is that the CD contains the bytes instead of memory, and on a CD the bytes are already decompressed so no decompression is needed.
c) Parts of a Player
Let’s take a look at the components that make up a typical MP3 player:
Data Port Memory Microprocessor Digital Signal Processor (DSP) Display Playback Controls Audio Port Amplifier Power Supply
The player plugs into your computer’s USB port or parallel port to transfer data. USB-based players transfer data many times faster than those that use the parallel port. The MP3 files are saved in the player’s memory. Memory types include:
Internal Flash memory CompactFlash cards SmartMedia cards Memory Stick Internal microdrive Iomega Clik! removable media
With the exception of the last two, these are all types of solid state memory. The advantage to solid state memory is that there are no moving parts; and no moving parts means better reliability and no skips in the music. The microprocessor is the brains of the player. It monitors user input through the playback controls, displays information about the current song on the LCD panel and sends directions to the DSP chip that tells it exactly how to process the audio. The DSP pulls the song data from memory, applies any special effects, or EQ, and streams it to the amplifier. The DSP runs a decompression algorithm that undoes the compression of the MP3 file and then a Digital-to-analog converter turns the bytes back into waves. The amplifier boosts the strength of the signal and sends it to the audio port, where a pair of headphones or ear buds are connected.
Playing MP3 files
All of the portable MP3 players are battery-powered. Most use one or two AA batteries and last for approximately 10 to 12 hours on a single charge. Many of
the players also have AC adapters so they can be plugged into a normal electrical outlet, and some even offer DC adapters for use in a car. The latest innovation is MP3 players that contain tiny hard disk drives. These drives can store 10 to 100 times more than flash memory devices can.
2) What It Can Do
Have you ever wanted to listen to your own mix of music made from more than one CD, or listen to CD quality music while jogging, without having to carry a heavy CD player? These are just some of the things that you can do with an MP3 player!
a) Overview
The MP3 format is a compression system for digital music that helps reduce the size of a digitized song without hurting the sound quality. Digital music is converted to MP3 format and made available for individual use, usually on the Web. You can download MP3 files from the Internet using your computer and special software, either commercial or freeware. You can also convert digital music from a CD into MP3 format using your computer and commercial or free software.
You can play MP3 files in three different ways:
You can play them directly on a personal computer You can decompress an MP3 file and record it onto a CD You can play MP3 files on a portable MP3 player (note: here we are referring to "MP3 player" as the device, rather than the software used to play the MP3 file on a desktop computer).
The advantage of MP3 players is that they are small, lightweight and rugged. They are a great way to carry your MP3 files with you!
b) What Can You Do with an MP3 Player?
With a portable MP3 player, a personal computer, and the appropriate software, you can do the following:
obtain free or low-cost music from the Web create your own mix of music (download MP3 files from Web, convert tracks from CDs) listen to near-CD quality music wherever you go (e.g., jogging or shopping) listen to music longer (up to 10 hours)
The easiest way to obtain songs in MP3 format is to find them on the Web.
c) Converting Your CD Songs into MP3 Files
If you have a CD collection, and would like to convert songs from your CDs into MP3 files, you can use ripper and encoder software. A ripper copies a song's file from the CD onto your hard disk. The encoder compresses the song into the MP3 format. By encoding songs, you can play them on your computer or take them with you on your MP3 player. The ripper and encoder software may come with your MP3 player. The specific instructions will vary with the individual software programs, but the following steps will definitely take place:
Place the CD from which you want to convert songs into your drive. Select the track(s) that you want to convert to MP3 format. Convert the selected track(s). Copy the new MP3 files on to your computer's hard disk.
Now you are ready to download these MP3 files into your portable MP3 player.
Downloading MP3 Files to an MP3 Player
Once you have MP3 files on your computer, you can use the software that came with your MP3 player to download the files into your MP3 player. Again, the specific instructions will vary depending upon your software program and player, but you will:
Create a playlist from your MP3 files (Web- and/or CD-derived). Plug the player into your computer's parallel or USB port (depending on the features of
your player). Transfer the MP3 files according to the instructions.
The process only takes a few minutes and gives you something like an hour of music in your MP3 player!
d) Using an MP3 Player
Once you have downloaded the MP3 files into your portable MP3 player, you are ready to take your music anywhere. Most MP3 players are small (3 in x 5 in / 7.5 cm x 11.5 cm, or less), lightweight, and solid-state. Because most players are solid-state, there are no moving parts to break down or skip, so the sound quality is uninterrupted regardless of your physical activity. MP3 players are equipped with various types of headphones or earpieces. Portable MP3 players can play music longer than a portable CD player. The length of play for a CD player is about 74 minutes, the length of one CD. However, the length of play for an MP3 player depends upon its memory capacity, which can be upgraded on some models. A standard MP3 player can play for about half an hour (32 MB) to an hour (64 MB). Some models can be upgraded with additional memory devices for as long as 10 hours of extended play.
2. Features
When you buy a digital audio player, the folowing features should be considered:
type of connection (parallel or USB) memory amount memory type controls head phones or ear phones LCD display size power supply
size (typically less than 3 in x 5 in, 7.5 cm x 11.5 cm) operating system support software unusual features options price ($100 - $500)
1) Memory
The MP3 files are saved in the player's memory. Most models are equipped with 32 megabyte (MB) or 64 MB standard. Memory can be upgraded in some models. The type of memory in MP3 players is either totally internal, totally removable, or some combination of the two (optional on some models). Memory types include:
Internal Flash memory CompactFlash cards SmartMedia cards Memory Stick Internal microdrive Iomega Clik! removable media
With the exception of the last two, these are all types of solid state memory. The advantage to solid state memory is that there are no moving parts, and no moving parts means no skips in the music and better reliability. The advantage of the new MP3 players equipped with hard disks is a huge song capacity. A hard disk can have anywhere from 300 megabytes to 2 gigabytes of space -- enough to hold days of music!
2) USB vs. Parallel Ports
If your computer is equipped with USB ports, then you definitely want to buy a USB player. USB connections can be 10 times faster than a parallel port connection, and they are a lot more reliable as well.
3) Controls
MP3 players usually have button controls, but some are equipped with joy pad interfaces. They have buttons for playback (i.e. skip, stop, pause, previous, next), volume, and controls for on-screen menus (arrows, enter). It might be
useful to test the MP3 player to see how the controls feel. Make sure that they are easy to operate, especially with one hand. If you plan to use your player in cold weather, you might want to test its feel with gloves on.
4) Power Supply
Most of the portable MP3 players are battery-powered. Most use one or two AA batteries and last for approximately 10-12 hours on a single charge. Many of the players also have AC adapters to plug into a normal electrical outlet, and some even offer DC adapters for use in a car.
5) Operating System
Because a portable MP3 player interacts with a personal computer to get its music, its software must be compatible with your computer's operating system. All MP3 players currently available support Windows 95/98, and most are compatible with Windows 2000 and the Apple Mac. If you are not using Windows 95/98, be sure to make sure the player's software is compatible with your machine.
6) Software
All portable MP3 players come with software to load MP3 files from your computer into the player. In addition, some models have software that will enable you to record songs from CDs (i.e. ripper, encoder). Some models have software that enables you to customize and edit your playlist. Finally, some models can handle data formats other than MP3, such as Windows Media (WMA) or AAC.
7) Unusual Features
Manufacturers offer distinctive styling, shape and added conveniences to make their players stand out from the pack. For example, one model has removable face plates of different colors, which can be interchanged. While most MP3 players look like small silver boxes that can be placed in a pocket or attached to a belt, there is a model shaped like a set of headphones that can be worn around the back of the head.
8) Options
Some optional features on portable MP3 players include belt clips or straps,
auxiliary speaker output, a cassette adapter for playing through a car audiocassette player and an FM tuner.
3. When You Shop
We've created an MP3 Player Feature Comparison chart for you to use as you research various models. Take it to the store with you and fill in the blanks for each model you are interested in. You may also want to keep an additional copy near your desk as you research MP3 player models on the Internet.
The feature comparison chart is available to you as a PDF. You will need the free Adobe Acrobat Reader to view it.
Download the comparison chart!
1) Operating system support
Drivers and support for Windows NT, Linux and other alternatives to Windows 95/98/2000 or Mac are very rare.
2) Memory amount
Some of the less expensive players provide a small amount of memory, maybe only 8 MB. This can limit the playing time drastically. Make sure that the memory is upgradeable, and that you don't end up paying more in the long run by having to buy additional memory for a "cheaper" model.
3) CD-based players
A new type of MP3 player that uses specially-recorded CDs to hold several hours of music is available. These players are, as you would expect, as big as normal portable CD players and look almost exactly the same. The difference is that they play CDs recorded with MP3 data files rather than music CDs. You typically create the CD using your computer's CD-ROM burner, and the disc you create can contain 100 to 200 MP3 songs. The advantage of this type of device is the large song capacity in an inexpensive medium. The disadvantage is the size of the player and the mechanical parts.
4) Copyright
Although you can find just about any song you want on the Internet, please remember that copyright laws still apply.
5) Copyright protection
Several manufacturers are working in conjunction with the music industry to embed copy protection in the digital music file. These encryption techniques require special code in the file and a means for the player to authenticate it. 6) Ease of use Often it's the little things that count, such as one-handed operation and a means to carry the player without having to hold it in your hand.
4. FAQ
What is MP3? The MP3 format is a compression system for music. The MP3 format helps to reduce the number of bytes in a song without hurting the sound quality. The goal of the MP3 format is to compress a CD-quality song by a factor of 10 to 14, without losing the CD quality of the sound. A 32 megabyte song on a CD compresses down to 3 megabytes or so on MP3. This lets you download a song in minutes rather than hours, and store hundreds of songs on your computer's hard disk without taking up that much space.
Is the sound quality of MP3 better than a CD? No. Because MP3 is a compression format, it throws away some of the information from a CD format. MP3 format uses characteristics of the human ear to design the compression algorithm. For example:
o o o There are certain sounds that the human ear cannot hear. There are certain sounds that the human ear hears much better than others. If there are two sounds playing simultaneously, we can only hear the louder one.
Using such facts about the human ear, certain parts of a song can be eliminated without significantly hurting the quality of the song for the listener. Compressing the rest of the song using well-known compression techniques shrinks the song considerably -- by a factor of 10 at least. When you are done creating an MP3 file, what you have is "near-CD" quality. The MP3 version of the song will not sound exactly the same as the original CD, because some of the song has been removed, but it will be very close.
Is a portable MP3 player better than a portable CD player? A portable MP3 player has the advantages of being smaller and lighter than a portable CD player. In addition, because a portable MP3 player uses solid-state memory instead of a spinning CD, it will not skip during playback. Finally, an MP3 player allows you to select your own variety of music.
Where can I find MP3 files for my MP3 player? All that you need to do is type "MP3" into any search engine and you will find that there are literally thousands of sites on the Web where you can download MP3 files. Here are just a few:
o o o o o o o MP3.com Scour
- looks across a number of MP3 sites for songs and software
Riffage Listen.com EMusic.com CDNow SonicNet.com
Can I record music from CDs for my MP3 Player? Yes, if you have a CD collection and would like to convert songs from your CDs into MP3 files, you can use ripper and encoder software to
convert your favorite songs. A ripper copies the song's file from the CD onto your hard disk. The encoder compresses the song into the MP3 format. By encoding songs you can play them on your computer or take them with you on your MP3 player. The ripper and encoder software may come with your MP3 player. To convert your CD songs into MP3 format, you will need: a computer a CD-ROM, DVD-ROM, CD-R, or CD-RW drive (internal or external) ripper/encoder software The specific instructions will vary with the individual software programs, but the following steps will definitely take place: Place the CD from which you want to convert songs into your drive. Select the track(s) that you want to convert to MP3 format. Convert the selected track(s). Copy the new MP3 files onto your computer's hard disk. Now, you are ready to download these files into your portable MP3 player.
Can I record music from my MP3 player to a CD? Yes, if you have a writable CD drive in your computer, you can convert (decode) your MP3 files into full-size CD tracks, and then save them to an audio CD. This allows you to listen to your favorite MP3 files on any CD player. WinAmp has a plug-in that will create full-size WAV files from an MP3 file, and some of the encoders will also decode. Once you have the full-size CD tracks, the software that comes with your CD-R drive will let you create an audio CD easily.
Is MP3 legal?
Yes, MP3 is merely a data compression format. However, what you do with that format can be legal or illegal. The distribution of music in MP3 format over the Internet has prompted much legal debate and action over copyright law. In fact, the Recording Industry Association of America recently won a suit against Napster over illegal distributions of MP3 files. This issue will become increasingly important as new music data compression algorithms become available. A good site for news about developments in Internet music is ZDNet Music.
What is sampling rate? Sampling rate refers to how often samples are taken from the original music signal. The higher the sampling rate, the better the sound quality, or fidelity; however, the higher the sampling rate, the more storage space is needed for the file.
What features are available in MP3 players? MP3 players have many varied features available, including: o operating system o type of connection (parallel or USB) o memory amount type o controls
o o o o o o o o
head phones or ear phones display (most models have LCD displays of different sizes) power supply size (less than 3 in by 5 in, 7.5 cm by 11.5 cm) software unusual features options price ($100 - $500).
5. Cool Facts
A German company, Fraunhofer Gesellschaft, originally developed the algorithm used in MP3 in 1987. They patented the technology in Germany in 1989, and in the United States in 1996. The Moving Pictures Experts Group (MPEG) was created in 1988. MP3 stands for Moving Picture Experts Group Audio Layer-3. MP3 format was originally intended to be used for HDTV systems. MP3 is actually part of the video format MPEG-2. There is no MPEG-3. The key features of the planned MPEG-3 format were integrated into MPEG-2. The next generation will be MPEG-4. An average CD song, 3 minutes long, takes up 32 MB of space. A 3minute MP3 song takes up about 1.6 MB, which means that approximately 20 MP3 songs can fit into the same space as one CD song. founded by Michael Robertson in November 1997, is the largest MP3 site on the Internet. MP3.com has over 562,000 songs by more than 87,700 artists.
MP3.com,