Rifts was created using a software called Techno Ejay, a software that allows you to use selections of several thousand sound clips to create your own music. You can also edit said sound clips to create audio that does not come default with the program. I've done a bit of that here, while using some of the default sounds.
This tune is the first attempt at the program that I was satisfied with.
It's also roughly 5 minutes in length, so, depending on your connection, might take a little time to load.