I have been to a number of rock concerts. By and large, during the time before the show starts, music is typically played on the PA system. For rock concerts, the PA music is usually the same genre, blended with classic rock favorites.
My question is, what is the term for this PA music? Overture comes to mind, but I believe an overture is performed by the artist which you went to attend. "House music" also comes to mind (since, when the concert is done, you bring up the "house lights"), but I don't think that is quite right either.