Grindcore is an extreme genre of music that started in the early- to mid-1980s. It draws inspiration from some of the most abrasive music genres – including extreme metal, industrial music, noise music and the more extreme varieties of hardcore punk. Grindcore is characterized by heavily distorted, down-tuned guitars, high speed tempo, blast beats, and vocals which consist of incomprehensible growls, or high-pitched shrieks.