In a nutshell, from memory which might be faulty, the standards are sometimes lower, yes, for music BM applicants; the audition is most important; and you can call individual schools to see what their benchmarks are in terms of grades and scores (some will be test optional). If you meet the minimum benchmark and have a great audition, you will probably do well.
Here is a site with test optional schools by the way. For academic merit awards, some of these will still want scores.
http://fairtest.org/university/optional