Pat Ford writes:

I asked the intellectual property guy here at work ( we have a guy
who does
only IP stuff) if I'm allowed to have mp3s, he said if you have the
cd/vinyl/tape a back copy is legal, I don't have to make it, as long
as only 1 copy is ever used at the same time.

I can see why someone might feel that way, but being that copyrights are
arbitrary, both in basis and enforcement, who knows? I suspect RIAA would
say you need to pay for an MP3 re-encoding even if you own the PCM CD, you
didn't buy a license for re-encoding, and those rights belong to the
author, too. The dogma is that you don't own the music itself in any
Platonic-ideal sense, you only own the one copy of PCM bit patterns on the
CD, and (implicitly) a right to make unlimited copies (again, copyright is
not about making copies per se) consisting of vibrating air pressure, and
vibrations of your tympanic membranes, and neural copies in your brain
cells. However, the copies in vibrating air, tympanic membranes, and
neurons cannot be in a restaurant or retail establishment, unless you pay
yet another public-performance license.