Art can be defined as the expression or application of human creative skill and imagination. A mass produced commodity is used to make money by producing the same thing. I think to simply label music either of these is an impossible task, music can be both.
Adorno suggests that the popular music industry is an all consuming production line, that churns out mass produced, inferior commodities; I agree with Adorno that a large part of the music industry is a money making machine. Take X-factor for example, the past four years have churned out cover after cover of recent songs, just because the public are familiar with them and therefore buy the single. However this music standardization cannot be applied to the whole industry. People who either write, produce or perform their song and do express imagination and creativity such as The Beatles can be defined as real musical artists.