To “face the music” is to meet or come up against the consequences of your actions, or to face a difficult or potentially dangerous situation head-on.The phrase boasts an almost 200-year history in English, with its earliest known uses tracing back to the early 19th century. But where does such a curious phrase come from? Or to put it another way, what exactly is the “music” that we’re proverbially “facing”?
THEATRICAL ORIGINS

There’s a popular theory that “facing the music” was originally an old theatrical expression, which presumably emerged in the music hall days of the 19th century. An actor or performer on stage would quite literally “face the music” by looking out from the stage into the auditorium, with the orchestra pit and its musicians sitting beneath them, waiting for their cue to begin playing. Perhaps, then, the phrase “face the music” came to refer to meeting a difficult situation head-on in the sense of a nervous player or entertainer finally coming to the moment of their performance or facing a hostile audience? Or perhaps it is meant to allude to an underprepared actor or performer, having not learned all their lines or lyrics, walking out on stage anyway for their big moment in the spotlight.
MILITARY ORIGINS

It’s certainly a convincing theory, but it’s not the only theory. There is another potential etymology here that claims that “facing the music” actually has military, not theatrical, origins—in which case, the “music” in question here might be the so-called musical “drumming out” of a dishonorably discharged soldier or officer.
In the past, a soldier who had in some way disgraced themselves during their military service would sometimes be ejected from the army as part of a punishing parade, meant to act as a kind of ritual humiliation. The soldier in question would be literally walked out of his service to the sound of his fellow soldiers beating their drums (and it’s for this reason, in fact, that we still talk of people being “drummed out” of office or out of positions of responsibility today). A soldier would face the music, ultimately, when whatever shady or unscrupulous behavior he had been up to had come to light, and he was set to be publicly punished for what he had done.
FACING THE MUSIC

So is the music we proverbially “face” in trying times the music of a theatre or music hall, or the rough music of a military punishment? It’s all but impossible to say. All the earliest recorded uses of the expression “face the music” don’t give us much in the way of hints, neither of its origins nor even the kind of context in which it might have originally been used. Until any further evidence emerges from the historical written record to shine a little more light here, we can’t say with any certainty which of these two theories—if, indeed, either—is correct.
