Chase (or "Synchronization Chase") is the process in which a "slave" device synchronizes with a "master" device that is already in progress.

Imagine you have a sequencer (master) and a recorder (slave) synchronized.

If you start playing the music from the middle, the recorder needs to "run" to the same position in the sequencer and align its timing with it.

This search and alignment process is the chase.

"Chasing Events" in MIDI

In the MIDI context, the chase has a very important extra function. If you start playing a song from the middle, the sequencer needs to know which instrument should be playing, what volume, note, etc.

The "chase events" function makes the sequencer "look back" from the beginning of the song to find the last MIDI commands that occurred before the point where you pressed play, such as:

• Program Changes: To load the correct timbre (e.g., piano, strings).

• Control Changes: To adjust parameters such as volume, pan, or the sustain pedal position.

This ensures that, no matter where you start playing, the instruments will always sound with the correct settings, as if the song had been played from the beginning.