Pedal point

Yeah.

The interesting thing about both of the things we're talking about, both vamps and pedal points or pedal tone or pedal, there's different ways to talk about it or call that what you would call it.

But it really started to get more popular, I think, in musicals sometime around the 60s.

Not that they weren't there before, because vamps especially certainly were in sort of the tradition of pedal point.