Copyright questions are rarely easy. Even the simple questions don't always have straightforward answers: What kinds of works are protected? What does it mean to be protected? Under current federal copyright law, both of those fundamental questions have enormously complex answers.
Although copyright evolved through the English common law and was adapted by into state common law in the United States, it is now primarily governed by federal statutes. As a practical matter, only those categories of works covered by the federal statute (listed in §102(a) of the Copyright Act) are protected. "Protection" gives the owner of the copyright certain specific, exclusive rights (subject to statutory exceptions), which the owner can prevent others from exercising without permission. But just to keep things interesting, even those exclusive rights vary depending on what kind of work is at issue, and even when the work was made.
One of the most complex of these rights is the right of "public performance," currently enshrined in §§106(4) and 106(6) of the Copyright Act. For certain works—such as plays, musical compositions and movies—the idea of a public performance is fairly straightforward. It means putting on the play, playing the piece or showing the movie to the public. The law gives the copyright holder the exclusive right to control that use. But difficulty arises with respect to "sound recordings," a relative newcomer to copyright protection. Under current federal law, the right to "public performance" of a sound recording is very restricted. It is essentially limited to transmitting the recording over a subscription digital radio or streaming service. And although that limited right is very important in the Internet age, its scope is further narrowed to apply only to recordings made after Feb. 15, 1972.
The question of the treatment of earlier recordings was recently examined in great depth by the New York Court of Appeals (at the request of the Second Circuit) in an opinion that examines and provides an excellent overview of this complicated area.