2-pop

The “2-pop” is the last number on the SMPTE countdown banner, which runs before a reel of a motion picture, television show, or commercial starts. Though they generally run unseen, we’ve all seen them before, as the banner is sometimes used for creative effect. It looks like an analog clock (complete with a rotating hand) with huge numbers on top of it counting down . . . 5, 4, 3, 2. The number 1 is never shown because that is when the video or film goes to black so it can be cued up. At the time of the 2 in the countdown, there is one frame of a 1,000Hz (or sometimes 400Hz) tone. The frame isn’t very long, so this tone sounds more like a “pop,” hence the name 2-pop. Its purpose is to verify that the audio and video or film are in sync with each other.