Short answer: we have no idea. Long answer: while there are pieces of musical notation that survive from different Roman periods, the method of deciphering them is not known, so anything that has been created is based on educated guesswork. Have a look at this thread: https://www.reddit.com/r/AskHistorians/comments/1hxrmb/what_did_popular_music_sound_like_in_the_roman/ lots more detail about the problems involved in reconstructing music when we don't know how the notation worked.