The first question: if the recording (or score) is for purposes of study, it does not infringe on copyright (unless said recording was done against the wishes of the creator). Teachers needing to show a student an example of something are allowed to use a recording for such a purpose. But yes, this gets murky, as when multiple copies are made.so does having a recording for yourself infringe on the same copyrights? it seems it would.
how old does it have to be to loose copyright?
Second question: a piece/recording enters public domain when:
Works created after 1/1/1978 - life of the longest surviving author plus 70 years - earliest possible PD date is 1/1/2048
Works registered before 1/1/1978 - 95 years from the date copyright was secured.
Works registered before 1/1/1923 - Copyright protection for 75 years has expired and these works are in the public domain.
We can thank Sonny Bono for having the copyright extended 20 years. It used to be 75 years and in 1998, his law changed it to 95 years.
And I believe the laws for this are slightly different in Europe.