I'm not a musician and music copyright is not my forte, so I appreciate when I find a good music copyright resource written by someone else. The Future of Music Coalition produced a fact sheet in 2012 entitled The Right to Terminate: a Musicians’ Guide to Copyright Reversion. As the site says:
Unlike most countries, the United States copyright law provides musicians and songwriters an opportunity to regain ownership of works that they transferred to outside entities, such as record labels and music publishers. Congress established this “second bite at the apple” for authors of creative works after a period of 35 years. “Termination of transfer” is not automatic, however, and there are certain steps creators must take to regain the rights to their works. This guide aims to shed more light on the process for the benefit of musicians and songwriters who are eligible to reclaim ownership of their creations.This is a very details fact sheet. If you are a musician, who wants to regain control of your copyrights, please read the fact sheet carefully, then consult an attorney. An attorney, who is versed in music copyright, can help you ensure that you pursue the correct path at the correct time.