Moises

Moises is an app for musicians that separates a song into its parts, such as vocals, drums, bass, guitar and keys, so you can mute or solo any of them. Most people use it to practice: take out the bass line and play along, slow a hard passage down without changing its pitch, or move the whole song into a key that suits your singer.

Around the stem splitting it adds the tools a practice session needs: a chord display that follows the song, a click track, a pitch and tempo control and loops for the bars you keep missing. It runs in the browser and as an app on phones, so you can prepare a backing track at home and use it in the rehearsal room. Separation quality depends on the recording; dense mixes leave more bleed between parts. Use stems from songs you don't own for practice only, and check the rights before you put them in anything you release.