Grindcore is an extreme genre o muisic that stairtit in the early- tae mid-1980s. It draws inspiration frae some o the maist abrasive muisic genres – includin daith metal, industrial muisic, noise an the mair extreme varieties o hardcore punk.
Grindcore is characterized bi hivily distorted, doun-tuned guitars, heich speed tempo, blast beats, an vocals which consist o incomprehensible grouls, or heich-pitched shrieks. Early groups like Napalm Death are creditit wi layin the grundwork for the style. It is maist prevalent the day in North Americae an Europe, wi popular contributors such as Brutal Truth an Nasum. Leerical themes range frae a primary focus on social an poleetical concerns, tae gory subject matter an black humor.
Grindcore relies on staundart hardcore punk an hivy metal instrumentation: electric guitar, bass an drums. Housomeivver, grindcore alters the uisual practices o metal or rock muisic wi regard tae sang structur an tone. The vocal style is "rangin frae heich-pitched shrieks tae law, throat-shreddin grouls an barks." In some cases, leerics daena even exist. Vocals mey be uised as merely an addit soond effect, a common practice wi baunds such as the experimental Naked City.
A characteristic o some grindcore sangs is the "microsang", lastin anerlie a few seiconts. In 2001, the Guiness Warld Records awardit Brutal Truth the record for "Shortest Music Video" for 1994's "Collateral Damage" (the sang lasts fower seiconts). In 2007, the video for the Napalm Death sang "You Suffer" set a new "Shortest Music Video" record: 1.3 seiconts. Ayont the microsang, it is characteristic o grindcore tae hae short sangs in general; for example, Carcass' debut album Reek of Putrefaction (1988) consists o 22 tracks wi an average length o 1 minute an 48 seiconts.
Mony grindcore groups experiment wi doun-tuned guitars. While the vinyl A-side o Napalm Death's debut, 1987's Scum, is set tae staundart tunin, on side B, the guitars are tuned doun 2½ steps. Their seicont album an 1989's EP wur tuned tae C♯. Harmony Corruption, their third full-length album, wis tuned up tae a D. Bolt Thrower went further, droppin 3½ steps doun (A).
Blast beat 
- Main airticle: Blast beat
The blast beat is a drum beat characteristic o grindcore in aw its forms, although its uisage predates the genre itsel. In Adam MacGregor's definition, "the blast-beat generally comprises a repeatit, saxteent-note figur played at a vera fast tempo, an dividit uniformly amang the kick drum, snare an ride, crash, or hi-hat cymbal." Blast beats hae been described as "maniacal percussive explosions, less aboot rhythm per se than sheer sonic violence." Napalm Death coined the term, though this style o drummin haed previously been practiced bi ithers. Daniel Ekeroth argues that the blast beat wis first performed bi the Swadish D-beat group Asocial on their 1982 demo. D.R.I. ("No Sense"), S.O.D. ("Milk"), Sarcófago ("Satanas"), an Repulsion an aa includit the technique prior tae Napalm Death's emergence.
Leerical themes 
Grindcore leerics are typically provocative. A number o grindcore muisickers are committit tae poleetical an ethical causes. For example, Napalm Death's sangs address a variety o anarchist concerns, in the tradition o anarcho-punk. These themes include anti-racism, feminism, anti-militarism, an anti-caipitalism. Ither grindcore groups, such as Cattle Decapitation an Carcass, hae expressed disgust wi human behavior, animal abuise, an are, in some cases, vegetarians. Carcass' wirk in pairticular is aften identifeed as the oreegin o the goregrind style, which is devotit tae "bodily" themes. Groups that shift their bodily focus tae sexual matters, such as Gut an the Meat Shits, are sometimes referred to as pornogrind. Seth Putnam's leerics are notorious for their black comedy, while The Locust tend toward satirical collage, indebted tae William S. Burroughs' cut-up method.