Quoting somebody else's song lyrics in your writing can be problematic, especially if your purpose is not scholarship or criticism (and even there, permission is often needed). This blog post, written by an author who is an attorney, offers a clear presentation of the issues, as well as suggestions -- but not actual legal advice! -- for how to seek permission to quote song lyrics.
Audio recordings have two copyrights that need to be considered: one for the recording itself and one for the music that is recorded. But while a symphony composed in 1910 is no longer protected by copyright, a recording of it made in 2010 still is. In fact, EVERY audio recording made in the United States is currently protected by copyright. For most of the 20th century, recordings were protected only by state and local laws. In 1976 the federal government assigned a life-plus-70-years copyright term to all audio recordings made after February 15, 1972, and the Sonny Bono Copyright Extension Act of 1998 set the copyright for all pre-1972 recordings to expire in 2067.
Like other copyrighted materials, audio recordings are subject to fair use and/or educational exemptions under certain circumstances. For guidance in these areas, click the fair use button at the top of this page or contact Linda Fairtile at Parsons Music Library.
If you want to avoid having to figure out copyright all together, there are many websites that offer music with Creative Commons licenses, some of which give you the legal right to use it in videos and other projects. Here are a few of them: