Originally posted by RattleandHum1988:[..]
Very cool, right sound, right pedal, but I do'nt think that's how Edge does it. I think what Edge does is set the pedal in "oscillation" mode, so when he plays the chord and rolls up the volume (or tone?) knob it "oscillates" creating that feedbacky siren sound. If you can find a video of Edge opening up that sound for Vertigo, you can see him play the chord on his country gent (from COBL) and roll up the knob, then while the sound is still going he quickly switches to the tele.
EDIT: here's how Edge does it: [YouTube Video]
The video link you put is fine to start the sound. That was how I did it too but didn't have the video on for that. That was the bit most of us already knew. What I was showing and hence the video was the pitch shift that Edge did later in the tour.
Early in the tour it was just getting the one upward siren. And Edge did that like the video you put up.
ALSO... you don't roll the volume up, you actually roll it down (off), the crunch disappears and you are left with the oscillation that makes the siren.
Later in the tour, when he began having the siren go up and down in pitch, like the Pasadena DVD, there is more to the sound. It isn't just the initial upware pitch of the siren. It modulates up and down (like the DVD). That was what I was showing - What (presumeably) Dallas is doing underneath the stage once the siren goes starts.