The freehand technique is a unique method used by percussion to produce a fast drum roll with a single hand. It is based around using the rim of a snare drum as the fulcrum point of the drumstick. By doing this, a drummer can produce two strikes of the drum with each full motion (one on the down stroke, and one on the upstroke).
This method has recently become quite popular in the drum community due to it being demonstrated in live drum clinics by world famous drummer Johnny Rabb. Johnny Rabb has been expanding his use of the Free-Hand Technique in his new project, "The Ten Finger Orchestra". He has been expanding his use of the free hand technique around the entire drum kit while mixing background music on a Digital turntable.
The freehand technique is also known amongst many drummers as the gravity blast.