The MP3 format compresses digital audio for storage on a computer or portable media player. MP3 encoders work by analyzing uncompressed audio files and removing sound frequencies beyond the range of human hearing. You can trim MP3 files using audio-editing software. These programs let you remove silence, long intros and other undesired sections of a sound file. You can then use the shortened file as a ringtone or in a mix on your MP3 player.
Download Audacity (see "Resources"). This freeware, open-source program supports MP3, AIFF, FLAC, OGG Vorbis and other compressed audio formats. You can use Audacity to trim MP3 files, split them in two and combine multiple tracks together into a single MP3. Click “File” and “Open” to select the MP3 file you want to trim. Use the “Selection Tool” to highlight the section of the track you want to remove in the audio editor window. Press the space bar to preview the highlighted selection. Press “CTRL” and the “X” key on your keyboard to remove the highlighted selection. Click “File” and “Save” to save the trimmed MP3 file to your computer.
Install mpTrim (see "Resources"). This freeware audio-editing program lets you shorten MP3 files. You also can use it to adjust the volume of an MP3 file and add fade-ins and fade-outs to shortened tracks. Click “Open” and select the MP3 file you want to trim. Click the “Time” tab and enter the start and end times where you want the cut to begin and end. Use the “Volume Control” slide bar to increase or lower the track’s volume. You also can add fading to the shortened MP3 track with the “Fade In” and “Fade Out” slide bars. Click “Save As” to save the trimmed MP3 file. MpTrim’s developers also offer a professional version of the program, which supports MP2 files.
Use MP3 WAV Editor (see "Resources"). This commercial audio-editing program lets you trim compressed MP3 files and uncompressed WAV files. It also will split a single MP3 file into multiple tracks, or join multiple files into a single track. Click “Add MP3” and select the MP3 file you want to shorten. Click the file in the “MP3 Files List.” Enter the times in minutes and seconds where you want the cut to begin and end in the “Start Time” and “End Time” textboxes. Click “Output Directory” to specify where you want the trimmed MP3 file saved. Click “Start” to create the shortened file. The developers of MP3 WAV Editor offer a free trial version of the program.