] Any digital content can easily be transformed into a sound
] file, or in technical copyright lingo, a "sound
] recording," which when fixed becomes a "phonorecord."
] Many compulsory license schemes only apply to "music" but
] since they don't define the term, or discuss changes in
] how audio works are categorized, one must assume that
] they are using the current definitions of "sound
] recording" and "phonorecord." Consequently, any creator
] of digital content can benefit from a music-only
] compulsory license scheme.

LawMeme - Compulsory Licensing - What is Music?