Part 3 · Rudiments · Chapter 27
The single stroke roll is simply alternating hands: R L R L. It sounds easy, but making both hands sound exactly the same takes years to master.
Quarter notes, then eighths, then sixteenths, all with alternating sticking.
The same roll, starting with the left hand. Your weaker hand needs this.
Accent every third note. The accent moves between the hands.
Close your eyes and listen. If you can tell which hand is playing, the two hands aren’t even yet.