By Will York

IF YOU PAID attention in high school physics class, you may remember seeing a grainy color video of a suspension bridge swaying in the breeze like a spaghetti noodle, then suddenly collapsing into the sea. This was the famous Tacoma Narrows Bridge disaster, one of the 20th century's great engineering blunders. It's a classic example of resonance, the phenomenon that also makes it possible for opera singers to break wineglasses and, if you believe the rumors, for rumbling sub-bass tones to make folks lose control of their bowels.

"That's an old myth," Khanate and Sunn O))) guitarist Stephen O'Malley says with a laugh. "But there are frequencies I've read about that shake your eyeballs, which I know has happened to people at Sunn O))) shows, vibrating sinuses and teeth."

If you're looking to test your body's response to sustained low-end frequencies, then Southern Lord – the label that's home to Khanate, Sunn O))), and a couple dozen other sludge-wielding doom-metal bands – is a good place to start. The Los Angeles company, which is run by Sunn O))) cofounder Greg Anderson, has been cornering the market on the slowest and lowest sounds in metal since the late '90s. This weekend a handful of the label's bands, including Khanate and Anderson's Goatsnake, descend on San Francisco as part of the "Three Days of Darkness" festival.

Taking the ugly cake

It's a close call, but Khanate have the distinction of being the slowest, ugliest act on Southern Lord's roster of dungeon-dwelling heavyweights. They're the latest in an evolutionary line that runs from side two of Black Flag's My War to the Melvins' Gluey Porch Treatments, from Swans to Sub Pop drone-metal act Earth. It's mood music for rotten moods – music that clears rooms at parties, annoys neighbors, and generally drives most people crazy.

"I like playing that way," O'Malley says of his guitar approach, which is founded on super-slow-motion tempos and extreme volume. "Things start bending in different ways. It's got an effect on your body, and it's ... pleasurable."

It may seem strange that anyone could derive pleasure from Khanate's music. Every aspect of it – the laryngitis-stricken vocals of Alan Dubin, the bitter dissonant guitar and bass of O'Malley and James Plotkin, respectively, and the lurching, mired-in-quicksand drums of Tim Wyskida – feels strategically chosen for maximum repulsiveness. Yet for all the nastiness of its components, the end product is undeniably compelling. Like labelmates Boris's snail-paced epic Absolutego and Sunn O)))'s Flight of the Behemoth, Khanate's latest album, Things Viral, is powerful antimusic that can alter your perception of time and rip you out of whatever crummy state of mind you're in.

"The music is so intentional in the way it's played," confirms O'Malley, who grew up in Ballard, Wash. – about 40 miles from Tacoma – and now lives in New York. He was once the guitarist for doom-metal cult favorites Burning Witch, and his bandmates have done time in avant-metal bands OLD, Blind Idiot God, and Phantomsmasher, among many others.

Like the Melvins, whose lurching, off-kilter rhythms were as important a part of their pioneering early albums as King Buzzo's charred guitar riffs, Khanate's skilled players deliver their music with a level of precision and subtlety that's often overlooked. "Khanate is really based around accuracy in playing," O'Malley adds. "There's no jam element in it by the time you're hearing it."

Not-so-sunny Sunn

The irony of an album like Things Viral is that the better you feel, the less you want to listen to it. On a sunny Saturday afternoon, it makes no sense, unless you live in a cave or a mental hospital. The same goes for music by Sunn O))) and several other bands on Southern Lord. "It's not a very social music," Anderson admits, speaking from his home in southern California after a recent Goatsnake practice. "It's misanthropic music that you listen to at home, by yourself. It's like isolationist music. A lot of the stuff Southern Lord puts out is like that."

Next to Khanate, Goatsnake are positively happy-go-lucky. Along with labelmates the Obsessed, Pentagram, Saint Vitus, and Electric Wizard, they represent the more '70s-rooted side of Southern Lord, playing time-warped blooze-rock and metal in the tradition of Black Sabbath and other less fashionable longhairs like Budgie, Free, Mountain, and Sir Lord Baltimore. They recently re-formed after a three-year hiatus and have a new EP, Trampled under Hoof.

Interestingly, Goatsnake used to record for San Francisco label Man's Ruin before it went under a few years ago. That label helped pave the way for Southern Lord by supporting the '90s doom- and stoner-rock craze but eventually shot itself in the foot by flooding the market with a sea of generic, subpar boogie-rock bands. Southern Lord picked up a few bands that were orphaned by Man's Ruin, including excellent Japanese trio Boris, but Anderson is determined to avoid spreading himself thin.

"Watching what happened with Man's Ruin kind of taught me a lesson to be more careful about what you put out," he confesses. "Be more scrutinizing with your tastes."

After all, there's a limit to how many times you can hear the same early Black Sabbath riffs get rehashed before you start contemplating rehab. Although, as Anderson says, "I don't even know if a lot of those bands listened to or liked Black Sabbath. It was just like they were just copying copies of Black Sabbath. They didn't know the roots. How many times can you hear the same Big Muff guitar sound? You know, the whole Kyuss-Fu Manchu thing – songs about vans and naked chicks."

Mood: doom

Scrutiny becomes more of an issue for Southern Lord as its profile grows, especially after the recent album by Probot, Dave Grohl's childhood-fantasy all-star metal project. Even so, Southern Lord's increasing popularity has as much to do with its establishing trusty-brand-name recognition via its lower-profile catalog of uncompromising, cult-favorite sludge-metal releases.

Anderson is surprised by the label's increasing notoriety. "It still blows our minds that people ... have the patience to digest what we're putting out. Because it's not easy. It's an acquired taste. You have to be dedicated and committed to listen to some of these records."

Equally surprising is the recent interest in doom metal by folks outside the traditional headbanger community. Keep in mind that during the '80s, bands like SST signees Saint Vitus were considered Neanderthals by hip punk and indie rockers. Yet earlier this year, ex-Vitus frontman Wino was featured on the cover of artsy mag Arthur. Highbrow mags such as Wire have heaped praise on Sunn O))); so has psych-rock aficionado Julian Cope, who recited a poem about O'Malley and Anderson on their 2003 album, White1. Meanwhile, Seattle's Growing are taking the Earth-Sunn O))) drone approach, softening up the harmonies and making it accessible to open-minded indie rockers. It's as if doom metal, against all the odds, has actually become cool – at least for a moment.

"It's a real interesting mix at some of the Sunn O))) shows," Anderson says. "It's like half metalheads, mixed with this straight, nerdy, experimental Wire crowd, or people who listen to Kranky records." Kranky is responsible for Growing's recordings, Godspeed You Black Emperor!'s debut, and space-rock band Jessamine's CD.

O'Malley has also noticed the revisionism, especially that directed toward his old band, Burning Witch, whose out-of-print recordings are prized collector's items. "That was the most totally unknown band when it was going on," he swears. Then again, the mid-'90, when Burning Witch was active, "wasn't the same kind of environment for that kind of music."

Sure, the Bush administration and Fox News probably deserve some credit for, uh, "fostering" the current doom-friendly environment, but Southern Lord deserves at least as much for its committed, formerly trend-bucking efforts. "I think everything goes hand in hand and kinda helps one another out," Anderson says.

'Three Days of Darkness'

Acid King, Bottom, YOB, Dirty Power, and Night after Night play Fri/3, 8 p.m., Elbo Room, 647 Valencia, S.F. $10. (415) 552-7788. Goatsnake, Khanate, Thrones, Graves at Sea, and Lair of the Minotaur play Sat/4, 8 p.m., Elbo Room. $14. High on Fire, Old Grandad, Asva, Asunder, Cephalic Carnage, Misery Index, Impaled, Subarachnoid Space, Brainoil, Wolves in the Throne Room, High Tone Son of a Bitch, and Drink the Bleach play Sun/5, 2:30 p.m., StudioZ.tv, 315 11th St., S.F. $20. (415) 252-7666. Three-day pass $40. www.threedaysofdarkness.com.