Genre Description - THRASH METAL

Thrash metal is a subgenre of heavy metal that is characterized usually by its fast tempo and aggression. Songs of the genre typically use fast percussive and low-register guitar riffs, overlaid with shredding-style lead work. Lyrics of thrash metal songs often deal with social issues, often using direct and denunciatory language, an approach which partially overlaps with the hardcore genre. The "Big Four" bands of thrash metal are Metallica, Anthrax, Megadeth, and Slayer, who simultaneously created and popularized the genre in the early 1980s.

Musical traits

The origins of thrash metal are generally traced to the late 1970s and early 1980s, when a number of bands began incorporating the sound of the New Wave of British Heavy Metal, creating a new genre and developing into a separate movement from punk rock and hardcore. This genre is more aggressive compared to its relative, speed metal, and can be seen in part to be a reaction to the lighter, more widely acceptable sounds and themes of glam metal.
Thrash metal generally features fast tempos, low-register, complex guitar riffs, high-register guitar solos, double bass drumming. Vocally, thrash metal can employ melodic singing to shouted vocals.
Most thrash guitar solos are played at high speed, as they are usually characterized by shredding, and use techniques such as sweep picking, legato phrasing, alternate picking, Tremolo picking, string skipping, and two-hand tapping. Thrash lead guitarists are often influenced by the New Wave of British Heavy Metal movement.
Thrash guitar riffs often use chromatic scales and emphasize the tritone and diminished intervals, instead of using conventional single scale based riffing. For example, the intro riff of Metallica's "Master of Puppets" is a chromatic descent, followed by a chromatic ascent based on the tritone. Rhythm guitar playing is characterized by extensive palm muting and down picking to give the riffs a chugging sound, along with extensive use of the pedal point technique (creating what can be considered a distinctive, 'thrashy' sound).
Speed, pacing, and time-changes also define thrash metal. Thrash tends to have an accelerating feel which may be due in large part to its aggressive drumming style. For example, thrash drummers often use two bass drums, or a double-bass pedal, in order to create a relentless, driving beat. Cymbal stops/chokes are often used to transition from one riff to another or to precede an acceleration in tempo.
To keep up with the other instruments, many thrash bassists use a pick. However, some prominent thrash metal bassists have used their fingers, such as Frank Bello, Greg Christian, Steve DiGiorgio, Robert Trujillo and Cliff Burton. Several bassists use a distorted bass tone, an approach popularized by Burton and Motörhead's Lemmy.
Lyrical themes in thrash metal include isolation, alienation, corruption, injustice, addiction, suicide, murder, warfare, and other maladies that afflict the individual and society. In addition, politics, particularly pessimism or dissatisfaction towards politics, is a common theme among thrash metal bands. Humor and irony can occasionally be found, but they are limited, and are the exception rather than the rule.