How does Daron Malakian of System of a Down go from clean to distorted with stepping

[Anthony Mendoza]

on a pedal? I saw System last night and I was right in front of Daron. It seemed like he went from a clean setting to a distorted setting without stepping on a pedal. Not that I'm questioning his playing, but I would like to know how to do that with my guitar.

 

[Jason]

The soundman may have done it for him, or you weren't watching close enough