What is copyright free music?

Answer 1

Music that has been registered with the Copyright Office. Under present law, copyright exists upon creation of a work; the registration process creates a legal record of the work's existence, and its approximate date of creation. Copyright notices are recommended for any works that go outside the creator's control, whether the works are formally registered or not.

Answer 2

"Copyright-free" music is in the public domain because protection has expired, or because it was never protected to begin with (a recording of the Marine Band playing Mozart, for example, would have no copyright).

"Royalty-free" music gives a broad license with a single fee, similar to stock photos. Many websites offer royalty-free bed music for advertising, for example.

Music by independent bands and artists is increasingly distributed with a Creative Commons license. While not strictly copyright-free, a CC license allows further distribution and often permission to remix or adapt as well.