To quote Klingon for the Galactic Traveler:
The word used for "compose" is qon. This verb also means "record" and is used whether the recording is by hand (that is, written or even etched in stone), in a medium suitable for a computer, or any other form. From the Klingon point of view, a song is not the product of an individual's mind. It has somehow always existed and is waiting for someone (the songwriter or, more accurately, song recorder, qonwI') to transcribe it (qon) and then present it (much) to others.
I interpret that as basically anyone who puts music into tangible form, whether that music is a song or an instrumental piece.