A standard
rudiment in
percussion, from which hundreds of
variants have sprung.
A double-stroke roll incorporates bouncing the stick twice with each hand before
alternating, and doing so in a clearly rhythmical and
controlled manner. A double-stroke roll's pulse is always locked into some sort of meter or tempo, as it were.
A common percussion exercise to teach double-stroke roll timing:
R L R L | RR LL RR LL ||
1 + 2 + | 1 + 2 + ||
This is also commonly found in groupings of
sixteenth notes, not just
eighth notes.