Victoria's summary is really useful, I think. In the case of audio,
consider this, too:
There was no federal copyright registration process for sound
recordings before Feb. 15, 1972. In my opinion, many "pre-'72"
recordings *might* be considered orphans, too, because their rights
holders are so difficult to track down. We may know how to contact
Sony Music Entertainment rights offices for Victor and Columbia output
but what about all the post-WWII independent labels? The challenges
faced in compiling the NRPB study conducted by Tim Brooks and Steve
Smolian, "Survey of Reissues of U.S. Recordings"
(http://www.clir.org/pubs/reports/pub133/pub133.pdf) are cases in
point.
Also, I think that we can add most recordings of radio broadcasts to
this category. 99.9% of them have certainly been abandoned by their
rights holders, at least until a party with rights gets wind of
someone trying to distribute them. It could be argued that these are
the opposite of "orphans." They have too many parents. But the
problems surrounding them are the same as those for orphans.
May I suggest that someone involved in the film orphans symposia
summarize the objectives and accomplishments of these conferences?
Then we can see how audio orphans might benefit from such attention.