If you really want to double major - unless you get a BA in music which tends to be more general, you’ll actually want a double degree. Please read this to help understand the differences: http://www.peabody.jhu.edu/conservatory/admissions/tips/doubledegree.html. There aren’t as many top music schools which fully support double degrees. There have been many posts on this site about the issue, and a google search with “double degree” “Music Major” “College Confidential” should turn them up.