No more sound recordings entering PD in the US until 2024, unfortunately, unless Disney and its bedfellows succeed in getting commercial copyright extended for the umpteenth-plus-one time before then--in which case...who knows? Fifty years from now, maybe our grandchildren and great-grandchildren will be legally free to do whatever they want to do with some of the earliest quad recordings.
https://web.law.duke.edu/cspd/publicdomainday/2023/
https://web.law.duke.edu/cspd/publicdomainday/2023/
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