Unfortunately, no musical notation existed in the West until the development of neumes in the late 9th/early 10th century. Any writings we have about Roman music have been transmitted without knowledge of how they were actually performed. We may have surviving lyrics of a song or a description of how music was perceived, but it is impossible to actually know and play Roman music.

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.