More than ever, pop music is a hybrid form. We're utterly accustomed to the way that it metabolizes textures, flavors and cadences from far-flung corners of the musical landscape. The fusion of styles only strikes us as exotic when we sense incompatibility between the aesthetic values of the source material. A prime example? Any combination of old-time, bluegrass or string band elements — music understood to be unspooling unbroken threads of tradition with some degree of reverence — and the synthetic beat-making techniques of hip-hop and dance music.