Key and Tempo are (I think, I am far from expert / novice even) the 2 most important points to consider. Most songs wont match so its required to pitch shift t

Key and Tempo are (I think, I am far from expert / novice even) the 2 most important points to consider. Most songs wont match so its required to pitch shift to align keys (which can also affect the tempo), and tempo because you want the beats to match up, otherwise it will sound like a mess. Your "Dreams Nation Army" works well because 7 nation army is pretty much a copy of Sweet dreams and they fit well together. VirtualDJ [0] allows to load multiple mp3's and can match key / tempo at the click of a button (manually or autodetect). They even built in the option to split stems using the spleeter tech [1] [0] - https://www.virtualdj.com/ https://www.virtualdj.com/ - if you want to use the spleeter tech, Win 10 is required. It can run in a VM though ;-) [1] - https://news.ycombinator.com/item?id=21431071 https://news.ycombinator.com/item?id=21431071