Scholarly journal articles are usually the most appropriate for academic papers. Characteristics of scholarly publications:
Examples include: Ethnomusicology, Journal of Musicology, American Music, Musical Quarterly, and Popular Music.
Popular magazine articles are useful when your topic is so current that scholars haven't written much about it or you need first-hand, contemporaneous reports (such as a newspaper or magazine review by a person who attended a work's premiere). Characteristics of popular publications:
Examples include: The New Yorker, Down Beat, Rolling Stone, and Variety.