A legal minefield
It all depends on the copyright laws of where you are. Most western countries, though, have similar principles underpinning their copyright laws.
With commercially released recordings (recordings an individual can buy for their own personal use, such as Cds, videos, DVDs etc), there are several copyrights involved:
a) the mechanical copyright owned by the original maker of the recording - in the case of a CD, the people who made and released the cd - NOT THE PEOPLE INVOLVED IN THE ORIGINAL RECORDING. There are, in some countries, time limits to these rights, but the minimum tends to be 50 years from initial release of the cd one buys.
b) the material which has been recorded may well also be subject to copyright. Music tracks certainly are. The actual performer(s) have a residual copyright in their original recordings, as do the composer(s), lyricist(s) and original publishers of the song. Again, most copyright laws have time-limits on these rights, but you're looking usually at 50 years after the original recording was made for the performers rights and, perhaps, 70 years after the death of the composer / lyricist.
c) for speech items, either the News organisation, or the writer ( sometimes both) hold copyright on everything they write for broadcast. e.g. The BBC owns copyright of all it's radio broadcasts from 1923 to date - even unscripted, on-the-spot reports from War Correspndents. Broadcasting organisations sometimes release material for inclusion in such compilations as you found, but they license their copyright solely to the producer(s) of the compilation ( and receive money for it.).
Sorry to bear bad news. The simple fact is that music recordings will eventually come into the Public Domain and be free of any copyright restrictions, but not until at least 50 years after their first release - and there's still the problem of the much more recent mechanical copyright on the compilations you've found. The news and other spech content in the compilations will have been licensed and, as far as I'm aware ( I work for the BBC ) there is no limit as to how long broadcasters can hold copyright on their material.
Some of the material on the 20 CDs may be out of copyright, but the only way to be sure is to check each one in great detail. HAving been involved in some copyright issues in the past I know what a long and maddening process this can be.