I was told that these “screamers” use a voice synthesizer (spelling?) to aid in the screaming as to not screw up their voice. Not all of them, but the ones who can afford it. Its this true? Reason being, I do not believe Otep is screaming. I can hear two sets of voices when she screams, and at first I thought it was a back up singer but none are listed, and you cant see anyone else singing when they perform. Thank you for any help you can give! =)