GRIND! : What’s faster than speed metal, angrier than punk? ‘Grindcore,’ a British style that shatters the limits of heavy metal.

At heavy-metal shows, sartorial custom demands that you wear a tour T-shirt from a band one level cooler than the one you’re seeing at the moment.

At a Judas Priest show, for instance, you would wear a Metallica shirt, at a Metallica show a D.R.I. shirt, at a D.R.I. show a shirt from somebody as obscure as Sepultura or Deicide.

At a Napalm Death show, like the one at the Country Club in Reseda recently, there is no cooler band, at least not at the moment. You strip off whatever shirt you’re wearing and put on a Napalm Death model fresh from the concession stand.

Napalm Death, a hard-core/thrash/metal/noise group from Birmingham, England, is pretty much acknowledged to be the most extreme band in the world--also the fastest, the most dissonant and, if it could afford better equipment, potentially the loudest.

On a 1989 British Broadcasting Corp. TV special about heavy metal, Napalm Death, as the ultimate metal band, got more air time than Megadeth or Guns N’ Roses. Another time, for a children’s educational program--called “What’s That Noise”--Napalm Death set up on one side of the British TV studio, a full symphony orchestra on the other: two logical poles of truth and beauty.

Live, the band grinds through with Altamont intensity, even when the stage is occupied by 100 stage divers at once. At the Country Club, Napalm was as awesome as Slayer or primo Black Flag.

“Grindcore,” the British heavy-metal movement inspired by Napalm Death and featuring such groups as Godflesh and Carcass, is rock ‘n’ roll pushed to its logical extremes: faster than speed metal, more morbid than death metal, angrier than hard-core punk.

Grindcore’s birth cries, on Napalm’s 1987 record “Scum,” sounded to the uninitiated like 20-second bursts from a Bessemer converter, overlaid with white-hot rage. It appealed more to the avant-garde composer crowd in this country than it did to the mainstream headbanger.

East Village composer John Zorn was an early fan, and the band’s first U.S. appearance was at the 1989 New Music America festival in Manhattan, along with concerts by Philip Glass and John Cage.

Napalm Death was in those days the heavy-metal equivalent of composer Anton Webern, whose dissonant miniatures had revolutionized classical music half a century before. One classic Napalm opus, a track on the “Peel Sessions” CD, lasted less than a second.

The band arose from the politically correct British hard-core scene in the mid-’80s, which was dominated by the speedy, far-left dialectic of such fervently political bands as Discharge and Crass, and evolved into the most extreme practitioners of that already extreme anarcho-punk.

The “Scum” album showcased songs so abbreviated that it sounded as if the needle was skipping across the record. It was also the record that launched a thousand grindcore bands.

“In the early days, it went hand in hand . . . extreme music and extreme attitudes against multinational corporations and various other stuff--I was constantly getting slagged for drinking a Coke,” said Napalm bassist Shane Embury, swigging a Coke, on a recent visit to Los Angeles.

“A lot of people became vegetarians because they were tired of people slagging them off for eating meat. Now that scene has dropped away a little bit, and now we have our own.”

Here come the new grindcore releases--three at a time, five at a time, from the appropriately named English label Earache, the official record company of grindcore.

Pop in a cassette--Carcass, Morbid Angel, Bolt Thrower, it doesn’t really matter--and hear the new boss sound, pulsing, whipping waves of guitar white noise, blast-beat drums and, on top of that, howling vocals-- Waaaaaauuuuughhhhhh! --that a Harvard philologist couldn’t identify as speech. If you crank it up loud enough, the sensation is not unlike a really bad, throbbing migraine headache, but without the pain.

This is the latest thing to catch the ear of heavy-metal America, this music that makes the screeching devil metal of Slayer seem as tame as a walk in the park with Martika. You won’t find the grindcore bands in the Billboard Top 100, but many of the bands have been embraced by the metal and independent cults in the way, say, Metallica and R.E.M. were before their big commercial breakthroughs.

Since January, when Combat/Relativity released the first batch domestically, each of the nine Earache LPs has charted Top 20 in the metal trades. Earache bands are as hip this year in the indie world as Sub Pop bands were last year and Homestead bands the year before that.

Carcass, a trio of hard-core vegetarian Liverpudlians that is considered by some to be grindcore at its hardest, features jaggedly dissonant guitar, slide shows of morgue slabs and butcher shops, and vivid, gross-out lyrics derived from dissection manuals--not that you can hear the words, screamed out as they are in the style of a wounded wolverine:

Purulent torso is a perfect maggots meal

Spilt cerebrospinal fluid is sucked up with zeal .

Selected song titles: “Cadaveric Incubator of Endo-Parasites” . . . “Swarming Vulgar Mass of Infected Virulency” . . . “Burnt to a Crisp.”

Carcass’ meat-is-murder thing might be exaggerated for comic, Grand Guignol effect. But at a Reseda Chinese restaurant, Carcass guitarist Bill Steer (who was the original guitarist for Napalm) insisted on going into the kitchen and making sure that the cook didn’t inadvertently slop some pork broth into his vegetarian dish, while drummer-lyricist Jeff Walker ranted quietly about the milk industry’s complicity in the meat trade.

Then they walked over to the Country Club and played their first L.A. date, an opening slot with Pestilence and Death.

Some of grindcore’s newer bands are closer to the straight-ahead death metal of Slayer or to the industrial disco of Skinny Puppy.

Morbid Angel is more or less a standard-issue devil-metal band out of the Florida scene that spawned Death and Obituary, riff rock speeded up to the point of insensateness and powered by a Napalm-style blast-beat. All its over-the-top wailing about lords of filth and plumed serpents of the deep is pretty funny (when you scan the lines on the lyric sheet). Morbid Angel is a headliner in Europe.

Godflesh, the critics’ fave, is an industrial Birmingham trio consisting of Justin Broadrick, G. Christian Green and Paul Neville. The music--mostly without vocals, powered by an incessant, distorted drum machine--is sort of gloomy like Consolidated or the early-’70s San Francisco industrial band Tuxedomoon but filled out with a grinding wash of guitar.

At Godflesh’s April Country Club show, where the group followed a sweaty, violent, 90-minute Napalm Death set, a guy in the slam pit was stabbed during the first song--gang trouble, apparently--and still nobody in the club wanted to leave.

“To me,” Napalm bassist Embury said backstage, “grindcore is an energy release. I’d like people to walk away from our shows knocked straight a bit, happy to be living. I don’t want anybody to walk away with the urge to murder somebody. That’s just pathetic.”

Faith No More may wear Godflesh T-shirts on stage, but Napalm Death is still the Beatles of grindcore.

On a bright morning, three-fifths of Napalm Death are slouched around the table of a West Hollywood diner, pushing greasy eggs around on their plates and staring glumly at the flaxen-haired fluff-rockers who strut around the room wearing pre-ripped jeans.

Embury, 23, heavyset and sullen, wipes the grease off his lips. When he talks, his mane of kinky long hair seems two sizes too small for his head.

“When we started,” he muttered, “we put two riffs together that might have lasted 20 seconds or something. We did what we did, and that was enough. It was the antithesis of the rock method. On our second album, we had 22 tracks, each like a minute, a minute and a half, and we pretty much proved that point, really. That was early Napalm Death.

“But people would just look at Napalm and get a laugh out of us. ‘What are they doing, man? . . . That’s just a big wall of noise. And what’s he singing? He’s not singing anything.’ ”

There were actual lyrics to begin with, though former lead singer Lee Dorrian basically just groaned in live situations. New singer Barney Greenway, 21, though definitely in the grindcore mold, seems almost like Perry Como in comparison: He howls words .

“Some people took us more seriously and paid us a bit of attention,” said 21-year-old guitarist Jesse Pintado, an L.A. native--Manual Arts High--who joined the band last year. (Mitch Harris, 20, and Mick Harris, 23, no relation, complete the lineup.)

“But once they heard the new LP,” Embury continued, “which is the same thing we’ve always done, only with a little longer songs and recorded clearly enough so that you can actually hear the music, those people said we sold out.”

But how could the music get more extreme without going backward?

“Well, maybe something with samplers,” Embury said, “and in the slow parts some heavy kind of noise. I’m still toying with the idea of making people release their bowels through music, a certain tone you can reach where people lose muscular control. You can’t hear it--it’s a low frequency--but it really churns your guts.”