Songs consist of patterns of notes, combined to create melodies. In the same way, you can combine whole songs to create new melodies, a merging process that can yield sometimes disastrous but sometimes amazing results. Professional DJs merge popular songs into a new mix called a "mash-up," but you do not need expensive DJ equipment to merge songs at home. You just need a couple of old songs that can potentially complement one another.
Open a digital audio recording program. Most important, choose a program that contains a multi-tracking interface, or the ability to stack parts of a song or recording on individual layers. Programs include ACID, Cubase, FL Studio, GarageBand, Logic, MixCraft, Pro Tools, Reason and a variety of free programs (see "Resources").
Drag your song files onto the project window of your audio software. If you need to copy the files from a CD, use a burning program like iTunes, Nero or Windows Media Player. Once you have the files saved onto your hard drive, just drag them anywhere onto the project window to create a new track (or layer) for each.
Adjust the tempo of each file to ensure that both songs play at the same speed. First select the track containing the file you want to edit. Among your "Effects" options (using appearing on your menu bar or mixer view), locate the "Speed" or "Tempo" option. Choose this effect, and use the sliders or number boxes to speed up or slow down your selected file as needed. Do this for each file until your songs play at the same speed.
Cut your song files. Most likely, your melodies will not align perfectly when you first insert them into your project. To line them up, start by removing unwanted portions of each file. Use the "Cut" or "Split" option on your menu bar or project window (often appearing as a pair of scissors) and eliminate the parts that you do not need, such as extended intros or repetitive verses.
Align the remaining portions of each file. If, for example, you want to make a melody only out of your choruses, you would drag the chorus of each song (as it appears in sound wave form on your horizontal track viewer) to the beginning, or left side, of the project window, where the timeline reads "0:00."
Mix each song file. One file may play much louder than the other(s), or contain too much bass or just not seem to fit into the mix. You can remedy this using your software's mixing options. Use the "Volume" sliders in your left column to adjust your volume for each track, or select your "EQ" option (usually appearing under your menu bar) to adjust the amount of bass (low frequency sounds) or treble (high frequency sounds) until your files blend naturally with one another.
Save your project as an MP3 or other audio file. Click "File" on your menu bar and select "Export" or "Save as Audio File." In rare instances, (such as with GarageBand), this option may appear on a menu other than the "File" menu. When your "Export" menu appears, insert a name for your melody and choose a format.