trying to learn the solo for this song but at 4:48 when johns bending the 21b23 he then makes this sound that sounds really rough and i have no clue how to create that on my guitar...

can anyone help??
I've actually wondered the same thing.

I think it might be a pedal he's using, but i'm not sure.
Paul Gilbert
Steve Vai
Joe Satriani
John Petrucci