Getting music permission
By Mauritz Kop LL.M.
If you are going to arrange (sheet) music that isn’t in the public domain yet, you or your publisher will need permission from the copyright owner. You can get permission by obtaining a mechanical license. Music licensing can be a complex process because you are dealing with various layers of music rights..
The copyright owner is usually the record company, or the artist itself. No permission is needed when arranging works that are in the public domain (mostly older classical works).
Public Domain Composers
Examples of well-known composers not yet in the public domain:
Rachmaninov, Bartok, Richard Strauss, Schoenberg, Prokovjev, Varese, Stravinky, Sjostakovic, Orff.
NB most popular Christmas songs are not yet in the public domain either so prior to releasing a cover, a remix or an arrangement you need to obtain the necessary licenses and get written approval (arrangement only) from the copyright owner(s).