From the 1980s through the mid-1990s, Filipino-American mobile DJ crews were at the center of a vibrant scene of house parties and events in Daly City and across the Bay Area. The mobile DJ community was a fertile soil for talent, from which grew the concept of the turntable as an instrument and of cuts and scratches as building blocks for composition. It also produced both DJ Qbert and Mixmaster Mike, who are among the most famous scratch DJs in the world. Cal State Long Beach sociology professor and journalist Oliver Wang joins us to talk about the history and influence of that scene, which he documents in his new book, “Legions of Boom.”