Maestro Pro
Backing Tracks & Sound
A backing track is a recording that plays with the score. The built-in instrument can play the notes on the page too.
Several tracks
A score can have more than one backing track, for example a rhythm section and a separate guide vocal. Add the first with Add Backing Track, then use Add Another Backing Track in the Inspector or the sound menu. They all play together, in time with the score.
Under Backing Tracks & Sound each track has its own switch, to turn it off without removing it, and its own level from -24 to +12 decibels. The first track is the one the score keeps time with, and Match Key & Tempo and the track editor work on it. The other tracks follow its speed and key, but not its edit lanes, and should be recordings that start together with it.
Reduce Vocals, on any track, cuts the singer down in a stereo recording by cancelling what is in the middle. It leaves a mono track, can take some middle instruments with it, and can't remove a voice from a mono recording.