Mystery Theme VII by KlionskyG

Question 5

What file extension is used to save data related to digital music editing? Instead of containing the amplitude of an actual or compressed sound recording (like .WAV or .MP3), it instead indicates what notes are played and when, how loud and for how long, which can then be synthesized by a computer. The standard was announced by Robert Moog in 1982.

Either the three- or four-letter extension is acceptable.