anyone knows the meaning of 'cranked up to eleven'?

Question

as title.
many thanks for answering.

Answer 1

It basically means with full volume or to do something at the very highest possible

Answer 2

it come from the movie This is spinal tap.
The guitar player not eing to bright is being interviewd and he explains how his amp goes to 11 so he keeps it on 10 and when he needs an extra push he puts it on 11.
the interveiwer says to him well why dont you just keep in on 9 and when you need an extra push put it on 10...
and he says kind of stupidly...
but this goes to 11.
Thats where that comes from.