I had mine with them today (ethnomusicology), and this is after having a lengthy call with one of their faculty members in December. It seemed far more informal than others I've had, more of a conversation about my research and methodological approaches, so I wouldn't be surprised if it was a person-by-person basis.
From speaking to multiple faculty members, it also seems like the different subdisciplines (ethno, musicology, music theory, comp) all do their own interviewing and deciding, then they come together as a department and advocate for their specific choices within the limited available spots. Another reason why it might not be standard.