#1
this might be kinda a noob question but at the very beggining of the following video theres this high pitched noise.......how do you do that....

LINK: http://www.youtube.com/watch?v=mBPGm4Fbo0Q
GEAR:
Black Epiphone G-310 SG
White Ibanez RG120
Digitech RP250 Multi-Effects Pedal
Raven RG100H and RG412 Half Stack