The MP3 file is one of the most popular ways to store music on computers and portable audio players today. The main reason MP3 became popular was because it compressed large audio files into much smaller sized files and still had good sound quality. But another advantage of MP3 files is that there are many software programs available that allow you to edit the sound and remove unwanted noises like pops and scratches. Editing software can also be used to adjust the overall sound level of an audio file.

One of the first things you will notice after you have collected a number of music files is that they don't all play at the same overall sound level. Even though one track may be a recording of rock band playing so loud that their amps are breaking up, it may be recorded at a lower overall volume setting than a song file which features only a solo acoustic piano. So as the songs play one after the other you have to adjust the playback volume to compensate for this difference. A playlist of 20 or 30 songs may have song files recorded at quite a few different volume settings. Having to constantly adjust the volume can be annoying.

Editing software can correct this by adjusting the overall volume level of each track so that they are all about the same. This is called normalization. Some editing programs have an automatic normalization procedure so that an entire directory of audio files can be normalized at one time.

If you have recorded some of older records or tapes onto audio files by using the "line in" jack on your computer's sound card, the recording will probably have some scratches or background hiss. Audio editing software can help reduce this type of noise. The overall clarity of the sound will be mostly dependent on the quality of the analog to digital converter in the sound card, but the results can be enhanced to some degree by editing software. The editing software will have filters that can be used to reduce background hiss on the entire track.

If you have a song file which suddenly cuts off just before the end of a song, you can use editing software to provide a gradual fade out instead.

There is quite a range of editing software available now, from consumer to professional level. One popular program is Sony's Sound Forge Audio Studio, which retails for about $70. There are some free programs available, but they tend to have limited editing capabilities.