well, from what i’ve seen so far, in order to get admitted in any course related to vocal performance, you need to pass something like an audition, where they examine your knowledge in harmony and other theory related stuff. i’ve never attended such course, but i have been thinking about it. but unfortunately, you will have to learn all these things in order to qualify. and so far, i haven’t found any courses that actually prepare you to enter a higher degree level. i don’t know how things are in the US, but here in europe i’ve only searched for colleges/unis in the UK. i have only been singing in a choir, so, i’m sorry if i can’t really be of any help in the matter..