Ah, FD, I believe you are referring to the ever-popular doctorate in EDLPS (educational leadership). It's a comparatively soft doctorate designed mainly for administrators and those with administrative ambitions. Because everyone knows that the principal and superintendent need to be Dr. So-and-so, right, especially if you work in an affluent suburb?
Music teachers tend to know their actual content area because most music ed programs consist of additional coursework on top of the music BA or BM degree (not unusual to come out with a dual bachelor's). And music majors undergo at-least-annual performance assessments of their musical skills in front of a faculty jury, often even if they're not performance majors, so you can't just pass your courses and forget about them. Probably the biggest difference for music ed is that the coursework is controlled primarily by the music department, not the ed department. E.g., pedagogy classes are taught by music faculty. Oh, yeah, and you have to audition to get in, thus demonstrating that you have some better-than-rudimentary skill in the area before being accepted for training.
