Migrations and technological advances in California following World War II, spurred radical changes in the production and development of popular music, most notably rock and roll. California largely lacked the entrenched traditions of the American Northeast, and in many ways its exploding population translated into the growth of a culture built around embracing newer methodologies, whether technological innovations or radical artistic departures. In large part owing to its increasing ethnic diversity during the economic expansion, California was uniquely poised to become a center of incredible postwar dynamism, especially when seen in the production, consumption, and stylistic development of music. Nevertheless, many of the radical departures in American music were contingent upon the contributions of a small group of inter-connected musical equipment manufacturers and musicians in California from the 1940s through the 1960s. As the United States experienced dramatic changes during the awesome postwar boom, Californian artists, merchants, and equipment makers exploited opportunities, making the Golden State the national trendsetter in musical developments both technological and stylistic. In particular, the invention, development, and further refinement of solid bodied electric guitars and basses in Southern California permanently changed how music would be made. The transformation of West Coast music would produce differing reactions nationally, while foreign developments would impact California, challenging its hegemony.