Many many threads on this subject over the years. (Try a google search.) Here are just a few:
http://talk.collegeconfidential.com/music-major/1776599-dual-degree-double-degree-joint-degree-programs-down-south-emphasis-on-b-m-b-s-or-b-a-b-s.html
http://talk.collegeconfidential.com/music-major/1735761-double-degree-programs-p1.html
http://talk.collegeconfidential.com/music-major/1716341-double-major-degree-music.html
http://talk.collegeconfidential.com/music-major/1762149-choosing-between-a-bm-degree-and-a-ba-degree-in-music.html
http://talk.collegeconfidential.com/college-search-selection/1596839-mathematics-and-music-double-major-double-degree-p1.html
http://talk.collegeconfidential.com/music-major/1580541-music-minor-and-dual-degrees-issues.html
http://talk.collegeconfidential.com/music-major/653686-liberal-arts-music-double-major-schools.html
http://talk.collegeconfidential.com/music-major/1773576-suggestions-for-double-degree-friendly-violin-faculty-to-visit-for-trial-lesson.html
http://talk.collegeconfidential.com/music-major/1343994-good-school-for-dual-degree-double-major-in-music-perfrmance-and-x.html
I could add more, but this is enough to get you started. And, of course, we always recommend starting right at the beginning with the Peabody essay about the different degrees. I’m sure there are many links to that essay in these threads.