Here is a quick, simple guide that you can follow. How to Edit MP3 using GarageBand Alternative - Filmora Video Editor for Mac At this point, we can now look at how to edit MP3 using Filmora Video Editor. Developed by a group of volunteers as open source and offered free of charge. Audacity is an easy-to-use, multi-track audio editor and recorder for Windows, Mac OS X, GNU/Linux and other operating systems. Free, open source, cross-platform audio software.