An anonymous reader writes "While Disney and others have done a great job pushing the end date for works entering the public domain ever further forward, most people have assumed that anything from before 1923 is in the public domain. However, it turns out that this is not true for sound recordings, in part due to an accidental quirk in copyright law history — in that Congress, way back in 1909, believed that sound recordings could not be covered by copyright (they believed the Constitution did not allow recordings to be covered), and thus, some state laws stepped up to create special copyrights for sound recordings. A court ruling then said that these state rules were not overruled by federal copyright law. End result? ANY recorded work from before 1972 (no matter how early it was recorded) won't go into the public domain until 2049 at the earliest."