Count off

A count off, count in, or lead-in is a verbal,[1] instrumental or visual cue used in musical performances and recordings to ensure a uniform entrance to the performance by the musicians[2] and to establish the piece's initial tempo, time signature and style.[3][4] Although a count off usually lasts just one or two bars,[2] 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.[3] 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.[5] A misleading lead-in, one which indicates a different meter than that of the piece, is a false trail.[6][7] Counting off is evident in musical genres other than Western classical and popular music; Ghanaian ethnomusicologist J. H. Kwabena Nketia has observed the benefits of such techniques in West African music.[8]

A two-bar percussive and verbal count off played on a closed hi-hat
Second shortest count off, "& four &", followed by one measure of drum beat for reference. Play (high tom-tom rather than voice) 

A silent count off, such as those given by an orchestral conductor using a baton, may be given as a value "in front" (e.g. "eight in front" refers to a count off of eight beats).[9]

In recorded music, the final two beats of the count off (one, two, one—two—threefour) are often silent to avoid spill onto the recording,[2][10] especially if the piece has a pickup. The count off is typically edited out after the recording has finished.[11] There are, however, instances where the count off is deliberately kept on a recording—sometimes even edited onto a recording. In the case of "I Saw Her Standing There" by The Beatles, the count off was edited onto a different take of the song.[12] A recorded count off can be made by musicians through an open microphone or through the studio's talkback system,[13] the latter being done by non-performing personnel such as the producer or engineer. The inclusion of a count off in a studio recording may give the impression of a live performance, as on the Beatles' "Sergeant Pepper's Lonely Hearts Club Band Reprise" (1967).[6]

Pre-count[14] and count-off[15] are functions of digital audio workstations which give an amount of click track—typically two bars[15]—before the recording begins.