As set forth in the MIDI standard, one MIDI timing byte is sent 24 times every quarter note. Therefore, if the tempo of a sequenced song speeds up, MIDI timing data is sent at a faster rate. MIDI timing bytes contain no indication as to where in a song they occur; they are similar to the tick of a metronome. With MIDI, location within a song is given by a song pointer message.
MIDI TIMING BYTE MESSAGE
Meaning of MIDI TIMING BYTE MESSAGE in English
Guitar English glossary. Английский словарь гитарных терминов . 2012