Katy Perry - Circle The Drain - E.T. - @ Liverpool Echo Arena - 18 Oct 2011

[@Sar234Qwe]

I was there had an amazing time

[@DVR01]

Any of you know what that siren sound was?

[@nicholasbert4475]

It was a siren

[@jordansharpe9405]

David Reyz it was part of the show

[@DVR01]

Indeed. In fact, I found the very link with the very sound: Bomb Siren Sound Effect (th-cam.com/video/8QWRhTpitZM/w-d-xo.html).