DJ is such a important role of dance music since 1906. Unfortunately most of the DJ don't have a chance to to manipulate music with gestures because DJ electronic instrument are mostly just knobs and buttons. With Groovy Hand, the new musical instrument, DJ can easily manipulate songs with gestures, therefore audience can easily understand what DJ is doing on the stage. Also, the audience feedback sound is highly used in [Groovy Hand] to create interactive performance.