There was a discussion previously about the copyright of musical performances in Canada (we have to pay a licensing fee to ReSound for these, as well as a licensing fee to SOCAN for the authors).
I have verified that the information provided by ReSound re musical performances was not entirely correct.
It is true that in June 2015, copyright was extended from 50 years to 70 years (from the end of the calendar year in which the performance was published). There are also a number of other conditions which can take copyright up to 100 years, but the basic length is 70 years.
However, THAT EXTENSION ONLY APPLIED TO MUSICAL PERFORMANCES STILL UNDER COPYRIGHT. Any performance whose copyright had expired (i.e., it was in the public domain) still remains in the public domain. That means that performances published (i.e. records were made available to the public) in 1964 or earlier were and still are in the public domain in Canada.
Of course, the songs themselves may still protected by copyright - that remains for a length of 70 years from the date of death of the last creator/author/writer.