Here is the link I used to get my info - http://imslp.org/wiki/Public_domain
While primarily Canadian focused, it does contain the U.S. material that I provided. Perhaps it's not entirely accurate. In any event, only the lawyers (and a court) can really decide if there's a copyright dispute. Case in point - the battle over the Amos and Andy OTR shows, effectively in the public domain until challenged, which ended with approximately half (the later ones) put back into copyrighted status (the copyright holder would argue that they never left that status).
Your Canadian Wiki leaves off the grid for US Sound Recordings. A completely different set of rules.
However, since BMI and ASCAP and SESAC are, near as I can tell the only organizations collecting said fees, and only collecting on behalf of WRITERS, I would be curious to know exactly who you would pay for use of the songs. the written lyrice and music would be public domain, but the actual performance e.g. "sound recording" is NOT. So you can sing and play the song without having to pay rights fees, but you can't play someone elses recording no matter the age. I can't remember if I included the link in my previous post....
http://www.copyright.cornell.edu/resources/publicdomain.cfm
Note that there are a couple small loopholes for a very small, specific part of the lot in the sound recordings category, except that in those cases, where the sound recordings ARe in the PD, the actual music and lyrics are NOT. We have three separate forces at work here, tune, lyrics, and recording. Which can all be different people, different times, different rights, different applicable laws.
tim
As for "broadcasting songs" the "new rights and fees" that are being demanded from commercial broadcasters is for payment to the ARTISTS who PERFORM the songs on the records. Up until this time the rights fees collected by the various rights organizations have gone to the writers/publishers, and NOT the performer or band (unless they happen to write their own material, and didn't get conned into giving away their rights to a publisher or music (record) company).
tim in Bovey