Mixing music involves adjusting the volumes of multiple audio tracks to ensure the track is balanced and no instrument overwhelms any other. Mac computers come with Garageband pre-installed, an audio program that features capable recording, production and mixing tools. Using Garageband is a simple, straightforward process that can result in a fully mixed song in a matter of minutes.
Start Garageband by clicking on the electric guitar icon in the taskbar.
Add a new track by clicking the "plus" icon toward the bottom-left of the screen. If you are at the mixing phase you should already have several finished audio tracks.
Arrange the tracks so that the timing is correct. Garageband features a simple drag-and-drop interface, and you can simply drag tracks to the beginning of a new measure. If you are mixing tracks you have recorded straight into Garageband, they should be ready to be mixed.
Adjust the volume by dragging the gray circle along the line in the "Mixer" section of a track. You can also adjust the balance of the track at this time.
Listen to the track once you have completed mixing it to make sure it is to your liking. Headphones are preferable for this, especially if you plan on adjusting the balance as well. Tweak the volumes of the tracks if you find they are not quite right.
Click on "Share" on the top navigation bar and choose to export the song into iTunes, onto a disc or as an .mp3 on your computer's hard-drive.
Other software, such as DJay, can be used on a Mac to mix audio.