be absolutely young, and scream.

If you're apropos to the array of...unreal attributes of metal choir like old Hetfield, or say...the screamy dude from Linkin Park, it's all in the recording studio. The action is alleged doubling, and they artlessly sing/scream the song a additional time, and brew both recordings together. The end aftereffect is array of like application a choir pedal; the articulation sounds immense. This immense-ness is acquired by slight differences in the recordings bushing in little aural gaps. The convenance is VERY old, and comes up with some amazing results.

So, the acknowledgment for reside shows would be...
maybe a choir pedal/effects engine...
a articulate furnishings processor with harmonizers...
cloning yourself and singing a duet....

im a little afraid because i ability overlook my lines.