Extreme metal
Extreme metal is a broad term for metal subgenres of a more aggressive style than traditional heavy metal.
This stems back to thrash metal in the 1980s, which mixed influences from hardcore punk and 1970s heavy metal. Doom metal and its subgenres trace their origins from older styles of metal, though much of what is considered "extreme doom" in modern times is heavily influenced by death and black metal. From thrash metal emerged other forms of extreme metal, such as black metal and death metal. Since this time extreme metal has expanded to cover many fusion, subgenres and other variations.
Characteristics
Extreme metal is characterized by its tempo, which may range from fast-paced, as in Death, and Thrash metal, to the extremely slow, as in funeral doom. Drummers often utilise double bass drumming and blast beats, though not all make use of these techniques. Vocals are performed in a growl, scream, or both, with some vocalists also using clean-sung vocals, though just how "clean" these vocals are varies widely. The guitars in extreme metal usually have distortion and fast paced riffs, and are often tuned below the standard E.