click track
A steady metronome pulse played through headphones during recording to keep musicians in time.
In Depth
A click track is an electronic metronome piped into performers' headphones during studio recording. It ensures all musicians play at exactly the same tempo, which is essential for modern production techniques like overdubbing (recording one part at a time) and editing (cutting and splicing between takes).
Not all musicians welcome click tracks. Some find them constraining — jazz and classical musicians rarely use them, preferring the natural ebb and flow of human timing. Rock drummers are divided: some embrace the precision, while others feel it kills the groove. Phil Collins and Stewart Copeland are famous for preferring natural feel over click-track perfection.
AC/DC's drummer Phil Rudd played so perfectly in time that producers initially thought he was using a click track — he wasn't. His natural timekeeping was simply metronomic.