Count off

A count off, count in, or lead-in is a verbal, instrumental or visual cue used in musical performances and recordings to ensure a uniform entrance to the performance by the musicians and to establish the piece's initial tempo, time signature and style. Although a count off usually lasts just one or two bars, it is able to convey the music's style, tempo, and dynamics from the leader (such as the conductor, bandleader or principal) to the other performers. A count off is generally in the same style of the piece of music—for instance, a joyful swing tune should have an energized count off. A misleading lead-in, one which indicates a different meter than that of the piece, is a false trail.