Thrash metal

Thrash metal is often regarded as the first form of extreme metal. It is generally characterised by its high tempos, complexity and aggression. Thrash metal guitar playing is most notable for the "chugging" sound it creates through low-pitched palm muted riffs, and high-pitched shred guitar solos. Drummers often use double-bass drums and hardcore punk-influenced d-beats. Vocals are most often shouted or sung in an aggressive manner. Thrash metal evolved from speed metal and NWOBHM at the beginning of the 1980s, although Black Sabbath's 1975 song "Symptom of the Universe" is often regarded as the earliest example of a thrash metal riff. Bands such as Metallica, Slayer, Anthrax and Megadeth spearheaded thrash metal and are referred to as the genre's "big four".