Latency

The amount of time by which an audio signal, or a MIDI message, is delayed as an unavoidable side effect of being passed through some form of processing, such as a sequencer or a digital interface. Latency causes particular problems in multi-track recording; for example, a musician who monitors himself via an audio signal passed through a computer may have difficulty coordinating his playing or staying on the beat if the latency in the monitor signal chain is excessive. Latency can cause tracks or MIDI sequences which appear to be on the beat during recording to be out of sync when played back.