"Alfred M. Szmidt" ams@gnu.org wrote: [...]
The GPL was designed for software, audio isn't software, a suitable license free audio license would be be a verbatim only, or a all permissive one.
Audio recordings can be software, and definitely Programs in the sense of the GPL, but I'd suggest an all-permissive licence is simpler too.
Creative Commons licenses (of several descriptions) are also widely used for audio recordings, of course. If in doubt, it should be easy to propagate the license terms as part of the recording (by referring, that is, not by including everything).