Press select and square for showing the music menu.
Press select and circle for resetting your settings.
Press select and triangle for turning the CPU up.
Press select and cross for turning the CPU down.
Press select and up for turning the volume up.
Press select and down for turning the volume down.
Press select and left/right for switching between songs.
Press select and home for muting in-game sounds.
Press select and start for enabling loop.
Press select and L-trigger for playing/pausing songs.
Press select and R-trigger for choosing between random/normal play.