https://www.ascap.com/help/music-business-101/money-copyright
In late 1998, Congress passed the Sonny Bono Copyright Term Extension Act which changed the 1976 Copyright Act by significantly increasing the length of time a song remains under copyright protection. Different rules though apply for songs written prior to January 1, 1978 and those written on or after that date.
For compositions written on or after January 1, 1978, the basic term of protection is the life of the writer plus 70 years. For example, if two 20 year old writers wrote a song in 2005, and one lives to be 50 and the other lives to be 100, the copyright protection for that song would last for 150 years from its creation. In this case, the protection would last from the time the song was written through the life of the last living writer (i.e. 100 years minus 20 = 80 years) plus an additional 70 years.
For compositions written prior to January 1, 1978, and which were still under copyright protection as of the time the Term Extension Act was passed, an additional 20 years of protection was added to the old law's terms. As the total number of years of protection for most pre-1978 songs under the 1976 law was 75 years (28 original years + 28 renewal years and a 19 year extension), the term of protection for these works has been extended to a total of 95 years from the original date of copyright.
For compositions written prior to January 1, 1978, and which were still under copyright protection as of the time the Term Extension Act was passed, an additional 20 years of protection was added to the old law's terms. As the total number of years of protection for most pre-1978 songs under the 1976 law was 75 years (28 original years + 28 renewal years and a 19 year extension), the term of protection for these works has been extended to a total of 95 years from the original date of copyright.
AI music generators are almost entirely trained on stolen copyrighted work.