Originally Posted by: Akira Vai also does this trick where he'll have the trem bar facing the opposite way to which it would normally face (so if you had your guitar with the head pointing towards the ceiling, the trem bar would be pointing towards the floor). He plays a note, or a flurry of notes and quickly hits the trem bar which makes it twang sorta. It sounds sweet, especially coupled with wah.
Dimebag (RIP) always did his natural harmonic tricks with the bar in that position too ... Of course Vai does more unusual tricks than anybody else , that's why he's ... VAI ! :D