Audio Techniques

 


 

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This page is designed for the novice Audio enthusiast and will hopefully serve as a guide to the MP3 extraction process: from downloading to CD Burning.  We will also discuss some of the most popular programs designed to adapt (encode) music to other formats. 

A music format simply means the method used to encode this particular piece of music.  This can also be called a "File Type" and will be discussed in more detail, in the section titled File Types.

 

Sources

There are many good links to Free MP3's on the internet, places where you can legally download Music that is in the Public Domain.   www.anymusic.com is one of the better ones.

There are also sites similar to the infamous Napster where you can download music directly from other music enthusiasts hard drives.  This file sharing, known as Peer to Peer (P2P) is actually a network of individuals sharing Music directly from their computer to yours.  The danger of this is that many users will share files that are still copyright protected and by downloading these songs, you are in violation of federal copyright laws.

Two of these are WinMX ( www.winmx.com ), Morphius ( www.musiccity.com ) and the latest one, KaZaA ( www.kazaa.com ).  There are many others but this should give you an idea of what P2P File Sharing is all about.

Some of these install "spyware" on your computer which will report your browsing habits back to their companies.  KaZaA is one of the worst about this, so I would recommend using the hacked version called Kazaalite, at  www.k-lite.tk.  It has many features disabled, but does not install the spyware.

 

File Types

 

There are many file types for audio files, but fortunately we are only going to deal with a few of them.  Some, such as Real Audio (ram) have not caught the public's attention and are therefore not as popular as the others.  Another is Windows Music (wma).  You will find this one used mainly with Windows operating systems, but once again, the others are just too firmly entrenched to pay much attention to the less popular formats.

The Three types we will primarily be working with are Compact Disk Audio (cda), MPEG layer 3 (MP3) and Wave Files (wav). 

CDA files are used to record music to a CD and are also what you will extract or Rip from the CD to make a compilation of music.  This is of little interest to us as most programs designed to extract audio from a CD will encode the selection to a Wave file automatically, and most programs used to record (burn) a CD will reverse this process and turn the original Wave file back to a CDA format..

 

This leaves us with only two commonly used formats, the Wav and the MP3.

 

Wav files are usually much larger than the popular MP3, requiring much more disk space for storage.  Wav files contain All the information there is about the music, in an uncompressed state.  They can be encoded in several different levels, however, which will create a larger or smaller file.  They can be encoded as Mono (1 channel) or Stereo (2 Channels).  Obviously the Stereo mode will provide better sound quality and reproduction when they are played, but many recordings which contain primarily spoken words rather than singing and instruments, will not require as high a Quality.

Wav files can also be encoded at several different frequencies.  We won't go too deeply into this subject as it would require an in depth study of sound as a waveform, and is unnecessary for our purposes.  The most popular setting is 44,100.  This is near CD quality and is the most widely used setting.  Recordings requiring less information, to be reproduced may be encoded at 22,050 or lower to make the final file size smaller so it takes less space on your hard drive.

Mpeg Layer 3 recordings (MP3) have become increasingly popular since they take less than half the disk space a wav file would require.  Being smaller they are more easily uploaded or downloaded from the internet.  This helps to explain their increasing popularity.

MP3 uses a technique known as compression to create a smaller file that still holds most of the necessary information.  This compression method introduces us to a new term called Bitrate or the number or bits utilized per second of playback. 
Confused????  Don't be.  It is unnecessary to thoroughly understand these terms, a long as you understand the concept.  A bitrate of 256kbps (kilobits per second) is near CD quality and will give the best playback.  128kbps is considered Normal encoding and is the most popular setting.  Less complex recordings will require less information and can be set accordingly...all the way down to 64kbps.  But with each step lower in the setting, some information is discarded.  There is a definite difference in hearing a song encoded at 256kbps and the same song encoded at 64kbps.

If you want a higher quality, encode at 256.  If you want the best combination of quality and size, use 128.  If it is a spoken recording (such as a comedian's album) go as low as 64.

One final word on which format you use.  If you wish to save this music on your hard drive, or you want to record a larger number of songs on a CD, use the MP3 format.  But a CD recorded in MP3 format WILL NOT play on the usual CD player.  We are beginning to see players that will play back MP3's but they are expensive and most modern DVD players will also play MP3's.  But Your Boom Box or Home stereo won't play them.

Wave files, On the other hand can be recorded to a CD that will play on almost any CD player.  For this reason, most users store the files in the MP3 Format, but will decode them to WAV files when they are ready to create a CD, then delete these files after Burning.

 

Oh yeah!!  The process of converting a music file to MP3 is called Encoding, and reversing this process to convert a MP3 to a Wav is called Decoding.

 

 

Procedures

To try to simplify all this, there are several steps to downloading Music and burning it successfully to a CD that will play in almost any CD Player.

1.    Make sure you have a good, Complete Downloaded MP3 File.  Check to make sure it plays all the way    through, to the end of the song.

2.    Decode the MP3 into a Wav file.  I recommend the freeware CD-Ex encoder.

3.    Normalize the wav files before burning to CD.  I use AudioGrabber.

4.    Use the best Possible Burning software.  My Preference is Nero Burning Rom.

5.    Use the proper Media.  CD-RW recordings will NOT play anywhere but on your computer.  Use CD-R.

 

 

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