There are many drum-apps you can play by tapping on screen buttons. Gravydrums takes a complete different path. By shaking your mobile in four different angels you can play four instruments. You can choose the instruments on each channel by drop down menu. Also the volume of channels can be adjusted. While learning gravydrums you can set two channels left and two channels right to the same instrument. Never beat towards hard objects, the mobile may break. Be careful when you have plugged an audio connector.