For me, Music Speed Changer allows me to just focus on the segment of the recording that I need to practice. I can pick an A point and a B point and it will only play between those two points. My learning tracks also come with my part in the left ear and the other parts in the right ear and I can use the balance control to focus on one and defocus on the other. I can also make playlists for the various performances coming up so that I can practice and memorize my music while I’m driving