The single stroke seven builds on the single stroke roll and the single stroke four drum rudiments. Instead of having a consecutive stream (roll) of alternating strokes like on the single stroke roll, there are seven consecutive single strokes - hence the name single stroke seven. The single stroke seven is played in triplets, just like the single stroke four - 1 trip let 2 trip let 3. Think of this pattern as a single stroke four with three extra triplets added in. All strokes should sound the same. Practice the single stroke seven with both left hand and right hand leading.
